Method of determining a filter for an ophthalmic lens as a function of a quantity representative of a dynamic sensitivity of the wearer's eye to a variation of a luminous flow

Abstract

The invention relates to a method for determining a filter for an ophthalmic lens intended to be placed in front of the eye of a wearer, said filter being able to improve or maintain the visual comfort and / or visual performance of said wearer. According to the invention, this method comprises: a) a step of determining a representative quantity of the dynamic sensitivity of the wearer's eye or both eyes to a variation in luminous flux, and b) a step of determining at least one optical characteristic of said filter as a function of the determined representative quantity.

Description

1 / 68 “METHOD FOR DETERMINING A FILTER FOR AN OPHTHALMIC LENS BASED ON A QUANTITY REPRESENTATIVE OF THE DYNAMIC SENSITIVITY OF A WEARER'S EYE TO A CHANGE IN LUMINOUS FLUX” TECHNICAL DOMAIN TO WHICH THE INVENTION REFERS

[0001] The present invention relates generally to the field of ophthalmic optics.

[0002] It refers, more particularly, to a method of determining a filter for an ophthalmic lens intended to be placed in front of the eye of a wearer, said filter being able to improve or maintain the visual comfort and / or visual performance of said wearer.

[0003] She also refers to a filter for an ophthalmic lens determined thanks to this method.

[0004] Finally, she refers to an ophthalmic lens equipped with such a filter. BACKGROUND OF THE TECHNOLOGY

[0005] There are solutions that allow a glasses wearer to be prescribed one or both ophthalmic lenses equipped with filters.

[0006] For example, in the field of therapeutic filters, different filters or types of filters may be offered to a patient depending on their condition (cataract, macular degeneration, diabetic retinopathy...).

[0007] The determination of the filter(s) is usually done in a very empirical way, by subjective tests testing different ophthalmic lenses equipped with filters on the wearer and retaining only the filters that provide the maximum improvement (see for example Rosenblum et al., ''Spectral filters in lowvision correction'', Ophthalmic Physiol. Opt. 20 (4), pp. 335-341, 2000).

[0008] Filters that improve contrast vision and / or reduce glare due to pathologies are, for example, offered by the ophthalmic laboratory Verbal in the CPF lens line (http: / / www.verbal.fr / fr / optique-basse-vision).

[0009] There are also solutions that correct color vision deficiency in the wearer. Document WO 2001 / 057583 describes, for example, a Petition 870180146180, dated 10 / 30 / 2018, p. 14 / 95 2 / 68 method according to which the spectral response of the carrier is determined and a filter is applied that restores color vision close to that of a normal eye.

[0010] The methods for determining filters are based on methods that are therefore: - whether subjective and not allowing for optimization of the filter's characteristic selection, - They want objectives, but limited to improving color vision.

[0011] During the determination of a filter, the carrier is often faced with compromises between several criteria to consider: variations in the lighting environment, associated visual requirements, aesthetics, etc.

[0012] Thus, known determination methods do not allow for an objective account of an individual's sensitivity to the characteristics of a potentially dynamic light environment in order to determine the filter to be placed in front of the wearer's eye.

[0013] Furthermore, they do not allow for consideration of the individual's dynamic sensitivity to light flux, that is, the greater or lesser adaptability of the wearer's eyes to a variation in light flux. OBJECT OF THE INVENTION

[0014] In order to resolve the aforementioned drawback of the prior art, the present invention proposes a method for determining a filter for an ophthalmic lens intended to be placed in front of the eye of a wearer, said filter being able to improve or maintain the visual comfort and / or visual performance of said wearer,

[0015] comprising: a. a step in determining a quantity representative of the dynamic sensitivity of the wearer's eye or both eyes to a change in luminous flux, and b. a step to determine at least one optical characteristic of said filter as a function of the determined representative quantity. Petition 870180146180, dated 10 / 30 / 2018, page 15 / 95 3 / 68

[0016] Thus, thanks to the method according to the invention, the dynamic sensitivity of the wearer's eye or eyes to variations in luminous flux is determined objectively or subjectively, in order to parameterize at least one optical characteristic of the filter to optimize the wearer's visual performance and / or visual comfort in a given task. The filter is thus customized for the wearer.

[0017] Dynamic sensitivity is understood here as the ability of the eye or eyes to adapt to an evolution of the perceived luminous flux, exhibiting, for example, an increase or decrease in illumination of at least 10 lux in a time interval between, for example, 0.1 and 60 seconds, for an initial illumination between 0 and 1000 lux.

[0018] The magnitude representing the dynamic sensitivity of the wearer's eye to variations in luminous flux is representative of the evolution of visual comfort and / or visual performance of the wearer as a function of variations in luminous flux.

[0019] This variation in luminous flux may correspond to a change in the intensity or wavelength spectrum of luminous flux over time, or even to a spatial change in luminous flux, for example a rapid displacement of the light source.

[0020] These visual performances and visual comfort may be limited either by insufficient dynamic sensitivity of the wearer to the luminous flux, or by the filter's own characteristics.

[0021] The filter parameters will be specifically adapted according to the visual precision required by the wearer and their ability to adapt to variations in luminous flux.

[0022] According to one aspect of the invention, the variation in luminous flux may correspond to: - refers to a variation in "real" luminous flux to which the wearer is subjected in the given task; in other words, the characteristic luminous flux is characteristic of the luminous environment in which the wearer is located to perform the visual task; - whether it refers to an "artificial" variation in luminous flux in the sense that Petition 870180146180, dated 10 / 30 / 2018, page 16 / 95 4 / 68 reproduces, at least partially, the luminous flux to which the wearer will be subjected, and is representative of at least one light source of visual discomfort or loss of visual performance for the wearer.

[0023] It is clear that one can consider determining, in step a), a plurality of quantities representative of the dynamic sensitivity of the eye or both eyes of the wearer to a variation of a luminous flux, and taking into account, in step b), a combination of these representative quantities to determine the said optical characteristic of the said filter.

[0024] According to a first aspect of the invention, the aforementioned step a) of determining the representative quantity of the dynamic sensitivity of the wearer's eye to variations in luminous flux comprises: a1) a step involving subjecting the patient to the aforementioned variation in luminous flux, and a2) a step involving measuring a quantity related to the eye's adaptation to this variation in luminous flux, performed on the patient subjected to the aforementioned variation in luminous flux.

[0025] The stage of subjecting the wearer to variation in luminous flux corresponds either to the wearer's situation in a luminous environment in which he is able to perform a given visual task, or to the reproduction, at least partial, of this luminous environment by a characteristic luminous flux controlled in such a way as to approximate as closely as possible the wearer's real situation.

[0026] Anatomically and physiologically, several components of the patient's eye interact in managing the variation in light flux. To determine the appropriate filter, it is useful to consider the set of physiological characteristics of the patient's eye and / or the structures connected to the eyes supporting this variation in light flux (multiparametric analysis). Depending on the capacity or fragility of this eye, the determined filter should relieve the eye of the component of light variation that is not generated in an ideal or adequate way for a given state of the eye. Petition 870180146180, dated 10 / 30 / 2018, page 17 / 95 5 / 68

[0027] It will also be understood that it will be useful to characterize the aforementioned variation in luminous flux with the help of a set of sensors, such as spectrometers, luxmeters, etc., allowing the measurement of the optical and photometric properties of light sources in the carrier's environment.

[0028] It is also possible to determine the characteristics of the luminous flux variation by simulation or optical calculations.

[0029] Step a1) is preferably repeated for different initial intensities of luminous flux.

[0030] In step a2), measurements are taken relating to one or both eyes of the subject subjected to varying luminous flux.

[0031] In certain modalities, the quantity representing the dynamic sensitivity of the wearer's eye to the aforementioned variation in luminous flux is chosen from at least one of the following quantities: - an objective physiological measurement of the carrier, - an objective physical measurement quantity of the carrier, - a subjective measurement quantity linked to the perception or expression of the bearer.

[0032] By “objective physiological measurement quantity” of the wearer, is meant any values ​​relating to the measurement of at least one parameter or at least one characteristic linked to the integrity and functioning of a component of the ocular system or structures related to this system. The choice of such a representative quantity allows the evaluation of the physiological capabilities of the eye or elements related to the treatment of a set or part of the characteristics of the luminous flux. This analysis makes it possible to identify the conditions or situations from which the wearer will not be able to cope naturally with the luminous flux. The prescription of a filter will then allow compensation for the associated loss of vision and / or visual comfort.

[0033] By “objective physical measurement quantity” of the carrier, is meant any value relating to the measurement of at least one parameter characteristic of a state of the ocular structure and functions or related structures by a measurement Petition 870180146180, dated 10 / 30 / 2018, page 18 / 95 6 / 68 Optical and / or photometric. The addition of physical instrumentation allows for the inferential characterization and quantification of a component of the ocular or related structure. The choice of such a representative quantity allows for the quantification, through physical measurement, of the capabilities and performance of one or more ocular or related structures in connection with glare processes. Depending on the structure studied and the results obtained, the filter characteristics will be adjusted differently to optimize comfort and / or visual performance according to the weakness(es) of the ocular and related structure considered.

[0034] By “subjective measurement magnitude linked to the perception or expression” of the bearer, is meant any responses expressed by the bearer through either a questionnaire or questions related to the tests performed in which the bearer must express what he or she perceived or felt visually. The choice of such a representative magnitude allows for the subjective determination of visual performance and / or visual discomfort felt and expressed by the bearer. This assessment allows for the definition of the conditions or situations in which the bearer achieves ideal visual performance / or ideal comfort, as well as the conditions of discomfort and loss of visual performance.

[0035] More particularly, according to certain aspects of carrying out the method according to the invention: - In step a1), the bearer is subjected to a predetermined light flux during a first exposure phase, then the bearer is placed in darkness during a second darkness phase and, in step a2), an average sensitivity is measured during a determined period of time after the start of the second phase and / or a darkness adaptation time corresponding to the time required for the bearer's eyes' sensitivity to light to reach a predetermined sensitivity value and / or - in step a2), the variation in pupil size over time is determined during at least the aforementioned variation in luminous flux from step a1). Petition 870180146180, dated 10 / 30 / 2018, page 19 / 95 7 / 68

[0036] It is also possible to determine the variation in pupil size over time during step a2) of returning to darkness.

[0037] According to a second aspect of the method according to the invention, the aforementioned step a) of determining the representative magnitude of the dynamic sensitivity of the wearer's eye to the variation of characteristic luminous flux comprises: a3) a step of subjecting the wearer to a questionnaire allowing the wearer's sensitivity to said variation of luminous flux to be assessed, a4) a step of collecting the wearer's responses to said questionnaire.

[0038] Thus, this questionnaire comprises, for example, one or more questions posed to the wearer about the different characteristics of the variations of luminous flux with which he is or will be confronted, and for which visual discomfort or loss of visual performance is reported.

[0039] According to certain aspects of the method according to the invention, in step a), the variation of the luminous flux comprises at least: i. - a temporal and / or spatial variation of the intensity of said luminous flux and / or ii. - a temporal and / or spatial variation of the spectrum of said luminous flux and / or iii. - a variation in space of a spatial distribution of said luminous flux and / or iv. - a variation in space of an angular distribution of said luminous flux;

[0040] When luminous flux is emitted by one or more light sources, the spatial distribution of said characteristic luminous flux corresponds, for example, to the given spatial extent of the source(s) (point source, extended source). As for the angular distribution, it corresponds, for example, to data from the angular emission diagram (directional / collimated source, non-directional source, etc.).

[0041] According to certain aspects of the method according to the invention, - the temporal variation of luminous flux intensity is performed with a Petition 870180146180, dated 10 / 30 / 2018, page 20 / 95 8 / 68 given time variation profile, and / or a given time variation rate, and / or a given variation amplitude and / or a given initial and / or final luminous flux intensity; - in step a), the carrier is subjected to different temporal variations in the intensity of the luminous flux, presenting different given temporal variation profiles, and / or different given temporal variation rates, and / or different given variation amplitudes, and / or different given initial and / or final luminous flux intensities.

[0042] Regarding other aspects of the method, according to the invention:

[0043] - in step b), at least one optical characteristic of the determined filter consists of: 1. - the absorption and / or transmission and / or reflection and / or shedding rate of said filter, 2. - the spectral response of the filter in question, 3. - the spatial distribution of these characteristics in the aforementioned ophthalmic lens, 4. - the presence of photochromic or electrochromic properties and the characteristics of these properties.

[0044] The filter cutoff rate can be measured using the method described, for example, in the ISO 89803:2003 standard, “Transmittance specification and test methods”.

[0045] As for the spectral response of the filter, it can correspond to the reflectance R^) or the transmittance T^), for example measured by means of a spectrometer using a standardized illuminator D65.

[0046] In a particular embodiment, the optical characteristic of the filter is also determined based on an indicator of the luminous flux and / or the visual need to which the wearer will be subjected in their activities.

[0047] According to certain advantageous features of the invention: - in step b), an optical transmission of the filter of at least one wavelength is determined, in at least one spatial zone of this filter. Petition 870180146180, dated 10 / 30 / 2018, page 21 / 95 9 / 68 filter, the lower the representative magnitude of the dynamic sensitivity of the wearer's eye determined in step a), indicating a low capacity for adaptation to a positive variation in the intensity of the luminous flux; - in step b), an optical transmission of the filter of at least one wavelength is determined, in at least one spatial zone of this filter, which is higher the more the magnitude representing the dynamic sensitivity of the wearer's eye determined in step a) indicates that there is a low capacity for adaptation to a negative variation in the intensity of the luminous flux; - In step b), the optical transmission of the filter is determined, for at least one wavelength, in at least one spatial zone of this filter, taking into account the dynamic sensitivity of the carrier to positive and negative variations in the intensity of the luminous flux; - in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux comprises a wearer comfort speed limit for variations in luminous flux and / or a comfort limit value for the luminous intensity perceived by the wearer during variations in luminous flux and, in step b), the optical transmission of the filter, of at least one wavelength, in at least one spatial zone of this filter, is determined taking into account this wearer comfort speed limit for variations in luminous flux and / or this comfort limit value for the luminous intensity perceived by the wearer during variations in luminous flux; - the filter exhibits photochromic or electrochromic properties that allow the passage between a light state and a darkened state of the filter corresponding to at least two different levels of light transmission of at least one wavelength, and in step b), the transmission level of at least one of the wavelengths is determined. Petition 870180146180, dated 10 / 30 / 2018, page 22 / 95 10 / 68 referred to as light and dark states as a function of the carrier's dynamic sensitivity to variations in luminous flux, that is, as a function of the representative quantity of this dynamic sensitivity determined in step a); - the filter exhibits photochromic or electrochromic properties that allow the passage between a light state and a darkened state of the filter corresponding to at least two different levels of light transmission of at least one wavelength and, in step b), a duration necessary to pass from one of the light and darkened states to the other is determined, which is shorter the shorter the representative quantity of the dynamic sensitivity of the wearer's eye determined in step a) indicates that there is a low capacity for adaptation to negative variations in the intensity of the luminous flux.

[0048] In particular, the aforementioned representative quantity of the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to an adaptation time of the eye to variations in this luminous flux.This may include, in particular, a recovery time of the eye's performance after a decrease in light flux intensity or a pupillary latency time after an increase in light flux intensity, which will be described in more detail later.

[0049] The aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux may also correspond to a measure of the luminous level from which a decrease in visual performance and / or visual comfort is observed.

[0050] According to other advantageous features of the method according to the invention: - The filter exhibits photochromic or electrochromic properties that allow the passage between a light state and a darkened state of the filter, corresponding to at least two different levels of light transmission of at least one wavelength. Petition 870180146180, dated 10 / 30 / 2018, page 23 / 95 11 / 68 step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to a wearer comfort limit velocity and / or a comfort limit variation for the variation in luminous flux and, in step b), a transmission difference between the light and dark states, and / or a passage duration between these two states and / or a passage velocity between one and the other of the light and dark states of the filter is determined as a function of this comfort limit velocity and / or this comfort limit variation; - The filter exhibits photochromic or electrochromic properties that allow the passage between a light state and a darkened state of the filter, corresponding to at least two different levels of light transmission of at least one wavelength, in step a). The aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to a comfort limit value for the luminous intensity perceived by the wearer during the variation in luminous flux, and in step b), the transmission level of the light and / or darkened state of the filter is determined based on this comfort limit value.

[0051] Whatever type of filter is considered previously, the optical transmission of the filter or the transmission level of one of the light or dark states of the filter is preferably determined for at least a given wavelength, preferably in at least a given wavelength range.

[0052] Similarly, the optical transmission of the filter is determined, or the transmission level of one of the light or dark states of the filter in at least a given spatial zone of the filter.

[0053] The aforementioned spatial zone of the filter can, for example, be a central or peripheral zone, upper or lower, a near, far or intermediate vision zone, a zone centered in the direction of the wearer's gaze.

[0054] According to certain aspects of the method according to the invention, the aforementioned Petition 870180146180, dated 10 / 30 / 2018, p. 24 / 95 12 / 68 The representative magnitude of the wearer's eye's dynamic sensitivity to variations in luminous flux is determined by taking into account at least one of the following parameters: - a parameter relating to the wearer's past, present and / or future light exposure habits: for example, average initial illumination of the eye before changes in luminous flux, activities performed / occupation, season, geographical location, artificial or natural light, duration of exposure... - a parameter relating to the wearer's static sensitivity to light flux: by "light sensitivity" of the wearer is meant any reaction or modification of comfort or visual performance, more or less intense and prolonged, linked to a temporary or continuous flow of light or stimuli. - a parameter relating to the amplitude of the temporal and / or spatial variation of the intensity and / or spectrum of luminous flux, - a subjective parameter relating to the wearer's visual performance under given lighting conditions and / or variations in lighting, - a subjective parameter related to visual comfort under given lighting conditions and / or variations in lighting, - a parameter linked to the age of the carrier, - a parameter relating to the use of sunglasses, - a parameter linked to the intraocular diffusion coefficient of the carrier's eye, - a parameter related to the density and / or distribution of macular pigment in the eye of the carrier, - a parameter linked to the retina's ability to adapt to light or darkness, - a parameter linked to the dynamics of pupillary response to light variation, including latency time, constriction amplitude, constriction velocity, and pupil recovery time after Petition 870180146180, dated 10 / 30 / 2018, p. 25 / 95 13 / 68 Lighting interruption - a parameter relating to a visual pathology or possible ocular anomaly in the patient, for example the presence of a diffraction defect or an artificial lens following cataract surgery. - a parameter linked to a range of visual comfort and / or visual performance, expressed or measured: for example, a recovery time of visual performance after a sudden change from light to darkness or vice versa; - the aforementioned step a) comprises a step of measuring the dynamic luminous flux to which the carrier is usually subjected; - The aforementioned luminous flux measurement step is performed with the help of a luminous flux sensor that is independent or integrated into a pair of glasses or a related object worn by the wearer.

[0055] According to another aspect of the invention's method, a further step is performed to determine a representative quantity of the environment in which the filter is used by the carrier and the said optical characteristic of said filter is determined taking into account this representative quantity of the environment.

[0056] This quantity representing the environment is, for example, related to the geographical location, including altitude, longitude, latitude, country... or to the season, which is linked to sunlight and, therefore, to the average intensity of the luminous flux perceived by the bearer outdoors. It can also be a quantity representing the fraction of time spent outdoors.

[0057] Thanks to this determination, it is possible to determine optical characteristics of an electrochromic type filter that controls these characteristics in order to limit the variations in luminous flux in such a way that the speed of the variations and / or the amplitude of these variations and / or the initial and final intensities remain below comfort limit values.

[0058] The invention also relates to a filter for an ophthalmic lens intended to be placed in front of the wearer's eye, said filter being determined by the method described above, in order to improve or maintain comfort. Petition 870180146180, dated 10 / 30 / 2018, p. 26 / 95 14 / 68 visual and / or the visual performance of the aforementioned individual.

[0059] In accordance with certain advantageous and non-limiting characteristics of the filter according to the invention: - This is an active filter of the electrochromic or photochromic type; This is a passive filter chosen from a set of pre-determined filters, such that the determined optical characteristic of the filter is close to the same optical characteristic of the chosen pre-determined filter.

[0060] The invention also relates to an ophthalmic lens intended to be placed in front of the eye of a wearer and comprising a filter as described above.

[0061] Detailed description of an embodiment example

[0062] More precisely, it is proposed to detail below four examples of a method for determining a filter conforming to the invention, in which: Example 1 refers to the determination of a filter based on macular pigment density; Example 2 refers to determining a filter based on the retina's adaptation to darkness and / or light; Example 3 refers to determining a filter based on the pupil's response to changes in light flux; Example 4 refers to determining a filter based on a prescription cone. Example 5 refers to determining a filter from a questionnaire, allowing the determination of the dynamic sensitivity of the wearer's eye to a variation in light flux.

[0063] The methods described below can be considered individually or they can be coupled.

[0064] The description of the examples that will follow relating to the accompanying drawings, given by way of non-limiting examples, will make clear what the invention consists of and how it can be carried out. Petition 870180146180, dated 10 / 30 / 2018, page 27 / 95 15 / 68

[0065] In the attached drawings: Figure 1 represents the curves of variation as a function of time of the sensitivity of the eye of a carrier after a variation in luminous flux, during the first 5 minutes after this variation, with and without a filter, in example 2; Figure 2 represents a curve of variation as a function of time of the sensitivity of the eye of a carrier after a variation in luminous flux similar to the curves in Figure 1, during the first 30 minutes after this variation; Figure 3 represents the transmission rate of a photochromic filter in a light state (CT1 curve) and in a dark state (CT2 curve); - Figures 4 and 5 represent the experimental results of average sensitivity in dB and average recovery time in seconds for a group of wearers fitted with a filtering ophthalmic lens (results T1) or not (results R); - Figure 6 represents pupil latency time as a function of visual comfort level for different patients, regrouped according to their ages (example 3); Figure 7 gives an example of a prescription cone determined in example 4; Figure 8 shows the influence of the luminous flux variation profile on the wearer's comfort illumination limit value; Figure 9 shows the influence of initial illumination of the luminous flux before the variation in the adaptation latitude of the wearer's eye; Figures 10 and 11 show the variation of a visual comfort indicator for two different wearers as a function of a variation in luminous flux illumination; - Figure 12 represents another profile of luminous flux variation to which the carrier is subjected in example 4; Figures 13 and 14 show the variation in recovery time of Petition 870180146180, dated 10 / 30 / 2018, page 28 / 95 16 / 68 visual performance as a function of the variation of the luminous flux illumination of figure 12 for two different carriers.

[0066] Variations in luminous flux can impact visual performance and comfort differently depending on the wearer. Advantageously, thanks to the method according to the invention, the filter is designed to preserve visual performance and wearer comfort as much as possible in case of variations in luminous flux.

[0067] The invention generally relates to a method for determining a filter for an ophthalmic lens intended to be placed in front of the eye of a wearer, said filter being able to improve or maintain the visual comfort and / or visual performance of said wearer, comprising: a. a step in determining a quantity representative of the dynamic sensitivity of the wearer's eye or both eyes to a change in luminous flux, and b. a step to determine at least one optical characteristic of said filter as a function of the determined representative quantity.

[0068] Preferably, the aforementioned magnitude representing the dynamic sensitivity of the wearer's eye to variations in luminous flux is representative of the evolution of visual comfort and / or visual performance of the wearer as a function of variations in luminous flux.

[0069] Next, we will discuss different photometric characteristics of luminous flux, namely: - its luminous intensity in candela in a given direction, which corresponds to the emitted luminous flux reduced to the unit solid angle centered in that direction, - the luminance of the light source that emits a flux equal to the luminous flux emitted reduced to the unit solid angle and the unit apparent area (cosine) in a given direction of observation, in candela per square meter, - illumination, equal to the luminous flux received per unit area, Petition 870180146180, dated 10 / 30 / 2018, page 29 / 95 17 / 68 in lux.

[0070] In general, the luminance of the source and the illumination of the luminous flux are linked to its intensity, and generally we speak of the intensity of the luminous flux. It is understood that a variation in intensity generally translates into a variation in luminance (if the source is the same) and in illumination.

[0071] The variation in luminous flux comprises at least: - a temporal and / or spatial variation of the intensity of said luminous flux and / or - a temporal and / or spatial variation of a spectrum of said luminous flux and / or - a variation in the spatial distribution of the aforementioned luminous flux and / or - a variation in space of an angular distribution of the aforementioned luminous flux.

[0072] In the case where the variation in luminous flux refers to a variation in the intensity of the luminous flux, it can obviously be a positive or negative variation in intensity, that is, an increase or a decrease in the intensity of the luminous flux.

[0073] All conditions for the variation of luminous flux were taken into account here, namely the initial and final intensities of the luminous flux and the rate of change of the luminous flux.

[0074] In the case of a temporal variation of the spectrum, it is the transmission values ​​as a function of each wavelength that vary. The average transmission, on the other hand, may remain the same.

[0075] The temporal variation of luminous flux intensity is performed with a given temporal variation profile, and / or a given temporal variation rate, and / or a given variation amplitude and / or a given initial and / or final luminous flux intensity.

[0076] In general, in step a), the carrier is subjected to different temporal variations in the intensity of the luminous flux, presenting different profiles. Petition 870180146180, dated 10 / 30 / 2018, page 30 / 95 18 / 68 of given time variation, and / or different given time variation rates, and / or different given variation amplitudes, and / or different given initial luminous flux intensities.

[0077] The optical characteristic of the filter determined in step b) may be, in particular: - the transmission of this filter of at least a given wavelength, in at least a given spatial zone of the filter, - the cutoff rate (absorption or reflectance) of this filter for at least a given wavelength, in at least a given spatial zone of the filter, - the transition time between a light state and a dark state for filters exhibiting photochromic or electrochromic properties with at least two light and dark states associated respectively with a first light transmission value of a given wavelength, preferably in a predetermined wavelength range, and a second light transmission value at this given wavelength or in this predetermined wavelength range, lower than the first.

[0078] The transmission Τ(λ) of the filter of a given wavelength λ is given by the ratio between the intensity I of the luminous flux transmitted by the filter and the intensity Io of the luminous flux incident on the filter: Τ(λ) = I / Io.

[0079] This transmission is between 0 and 1 or expressed as a percentage.

[0080] This transmission can result from the passage of light flux through an absorption filter or an interference filter.

[0081] For an absorption filter, the absorption Ά(λ) of the filter is equal to one minus the transmission of the filter: Ά(λ) = 1- Τ(λ), or Ά(λ) = 100%- Τ(λ) in percentage.

[0082] For an interference filter, the reflectance R(X) of the filter is equal to one minus the transmission of the filter. Petition 870180146180, dated 10 / 30 / 2018, page 31 / 95 19 / 68

[0083] Next, unless otherwise stated, the term “transmission” or “absorption” refers indifferently to an average transmission or absorption of the filter over the entire spectrum of the incident light flux considered or to a transmission or absorption spectrum exhibiting different values ​​over a wavelength range of interest.

[0084] As will be evident from reading the following examples, in general, in step b), an optical transmission of the filter of at least one wavelength is determined, in at least one spatial zone of this filter, which is lower the more the magnitude representing the dynamic sensitivity of the wearer's eye determined in step a) indicates that there is a low capacity for adaptation to an increase, also called a positive variation, in the intensity of the luminous flux.

[0085] Similarly, in step b), an optical transmission of the filter of at least one wavelength is determined, in at least one spatial zone of this filter, which is higher the more the representative magnitude of the dynamic sensitivity of the wearer's eye determined in step a) indicates that there is a low capacity for adaptation to a decrease, also called a negative variation, in the intensity of the luminous flux.

[0086] Furthermore, preferably in step b), the optical transmission of the filter is determined, for at least one wavelength, in at least one spatial zone of this filter, taking into account the dynamic sensitivity of the carrier to positive and negative variations in the intensity of the luminous flux, that is, the quantity representing this dynamic sensitivity determined in step a).

[0087] The determined transmission value then represents an ideal compromise based on the dynamic sensitivity of the carrier.

[0088] In particular, in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux may comprise a wearer comfort limit velocity for variations in luminous flux and / or a comfort limit value for the luminous intensity perceived by the wearer during variations in luminous flux and, in step b), the optical transmission of the filter, of at least one wavelength, in at least one spatial zone. Petition 870180146180, dated 10 / 30 / 2018, page 32 / 95 20 / 68 of this filter, is determined taking into account this wearer comfort limit for the variation in luminous flux and / or this comfort limit value for the luminous intensity perceived by the wearer during the variation in luminous flux.

[0089] When the filter exhibits photochromic or electrochromic properties that allow the passage between one and another of a light state and a darkened state of the filter corresponding to at least two different levels of light transmission of at least one wavelength and, in step b), the transmission level of at least one of the aforementioned light and darkened states is determined as a function of the dynamic sensitivity of the carrier to variations in luminous flux and / or a duration required to pass from one to another of the light and darkened states that is shorter the more the representative magnitude of the dynamic sensitivity of the carrier's eye determined in step a) indicates a low capacity for adaptation to negative variations in the intensity of the luminous flux.

[0090] In general, if the carrier is more affected by variations in increasing light intensity, a photochromic filter with a fast transition to the darkened state is proposed. If the carrier is more affected by variations in decreasing light intensity, a photochromic filter with a fast transition to the brightened state is proposed.

[0091] For example, the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to an adaptation time of the eye to variations in this luminous flux (see examples 2 and 3).

[0092] This adaptation time is, for example, a recovery time for eye performance or a pupil latency time.

[0093] Recovery time is the time required to regain initial comfort and / or performance of the eye. It corresponds to the time required for the regeneration of photoreceptor pigments after a change in light flux or a level of illumination saturating the retina, during a return to darkness.

[0094] Pupil latency (or reaction time) is the time required for the pupil to adjust its size after a change in light flux, Petition 870180146180, dated 10 / 30 / 2018, page 33 / 95 21 / 68 whether in the case of an increase or a decrease in the intensity of the luminous flux.

[0095] According to another example (see example 4) the filter exhibiting photochromic or electrochromic properties, in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to the variation of luminous flux corresponds to a wearer comfort limit velocity and / or a comfort limit variation for the variation of luminous flux and, in step b), a transmission difference between the light and dark states, and / or a passage duration between these two states and / or a passage velocity between one and the other of the light and dark states of the filter is determined as a function of this comfort limit velocity and / or a comfort limit variation.

[0096] Alternatively, in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to a comfort limit value for the luminous intensity perceived by the wearer during the variation in luminous flux and, in step b), the transmission level of the light and / or darkened state of the filter is determined as a function of this comfort limit value (see example 4).

[0097] In general, the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux is determined by taking into account at least one of the following parameters: - a parameter relating to the wearer's past, present and / or future light exposure habits: for example, average initial illumination of the eye before changes in luminous flux, activities performed / occupation, season, geographical location, artificial or natural light, duration of exposure... - a parameter relating to the static sensitivity of the carrier to luminous flux, - a parameter relating to the amplitude of the temporal and / or spatial variation of the intensity and / or spectrum of luminous flux, - a subjective parameter related to the visual performance of the wearer Petition 870180146180, dated 10 / 30 / 2018, page 34 / 95 22 / 68 for given light conditions and / or light variation, - a subjective parameter related to visual comfort under given lighting conditions and / or variations in lighting, - a parameter linked to the age of the carrier, - a parameter relating to the use of sunglasses, - a parameter related to the density and / or distribution of macular pigment in the eye of the carrier, - a parameter linked to the retina's ability to adapt to light or darkness, - a parameter linked to the dynamics of pupillary response to light variation and / or another pupillary characteristic, - a parameter relating to a visual pathology or possible ocular anomaly in the patient, - a parameter linked to a range of variation in visual comfort and / or visual performance, expressed or measured.

[0098] In general, the data collected by a questionnaire or by measurements are transmitted to a computer processing unit programmed to perform the subsequent analysis steps. This computer processing unit performs step b) of filter determination.

[0099] According to a first possibility, the information processing unit has a memory that stores a list of different available filters. The filter determination is then performed by the computer processing unit, which chooses the filter from the list that presents the characteristics closest to the optical characteristics determined based on the quantity representing the dynamic sensitivity of the filter determined in step a).

[0100] All available filter types are listed with their characteristics. For passive filters: absorption and / or transmission spectra, their polarization, and the spatial variation of the absorption or transmission spectrum on the filter surface are specified.

[0101] For passive interference filters, the variation of the spectrum of Petition 870180146180, dated 10 / 30 / 2018, page 35 / 95 23 / 68 transmission and / or reflection as a function of the angle of incidence of light on the filter is also listed.

[0102] For photochromic filters: the rate of transition from one state to another, the transmission or absorption spectrum, or the minimum and maximum average transmission of each light or dark state are recorded.

[0103] For active filters: the rate of transition from one state to another, the transmission or absorption spectrum, or the minimum and maximum average transmission of each light or dark state are recorded, as well as the presence of sensors to characterize the light environment, filter management sensors (transmission management, speed, sensors linked to filter control, etc.) and characteristics of the incorporated technology (energy consumption, system stabilization, information communication).

[0104] According to a second possibility, the treatment unit determines the desired optical characteristics in step b) and orders the manufacture of an ophthalmic filter and / or lens fitted with a filter comprising those precise optical characteristics.

[0105] The invention also relates generally to a filter for an ophthalmic lens intended to be placed in front of the eye of a wearer, determined by the method described above, in order to improve or maintain the visual comfort and / or visual performance of said wearer.

[0106] This filter belongs to an ophthalmic lens intended to be placed in front of the wearer's eye, for example, in a spectacle frame.

[0107] According to a first family of methods, the determination of the magnitude relating to the dynamic sensitivity of the bearer's eye is carried out from an objective quantitative measurement of a physical or physiological characteristic of this bearer's eye.

[0108] This first family groups examples 1, 2 and 3. EXAMPLE 1

[0109] In this example, a method for determining a filter according to the invention will be described, whereby, in step a), the aforementioned quantity relating to Petition 870180146180, dated 10 / 30 / 2018, page 36 / 95 24 / 68 The dynamic sensitivity of the carrier's eye is determined based on one or more measured values ​​of macular pigment density and / or distribution in the carrier's eye.

[0110] Macular pigment (MP) is located in the macular zone of the retina, in the central 6° of retinal eccentricity ε (Wolf-Schnurrbusch et al., “Ethnic differences in macular pigment density and distribution”, Invest. Ophthalmol. Vis. Sci. 2007, 48(8), p. 3783-3787; Bernstein PS, “The value of measurement of macular carotenoid pigment optical densities and distributions in age-related macular degeneration and other retinal disorders”, Vision Res. 2010). It is composed of lutein and zeaxanthin (the carotenoids of the eye). It is located in the outer plexiform layer of the retina and has the function of absorbing the light flux within a specific range of wavelengths between 400 and 500 nm, preferentially between 430 and 480 nm. This macular pigment also exhibits a peak absorption of approximately 40% around a wavelength of 460 nm.

[0111] The macular pigment functions to protect cellular tissues from the harmful effects of photo-oxidation caused by blue light with wavelengths between 400 and 500 nm, preferably between 430 and 480 nanometers, and to reduce the diffusion of blue light by absorbing it.

[0112] With age, the density of this macular pigment recorded here decreases in such a way that there is a strong correlation between the concentration of this macular pigment and the risk of developing age-related macular degeneration, or “DMLA” (see for example Beatty S. et al., Invest. Ophthalmol. Vis. Sci. 2001; 42:439446).

[0113] Macular pigment can have a different spatial distribution depending on the individual. A peak or toroid-shaped distribution is distinguished. The former shows a progressive distribution of macular pigment density as a function of eccentricity. It is also possible to observe a central cavity in the spatial distribution of macular pigment at the macular level. Then it is referred to as a "donut" or Mexican hat-shaped distribution.

[0114] Macular pigment has an impact on the visual performance of a Petition 870180146180, dated 10 / 30 / 2018, page 37 / 95 25 / 68 individual: it allows, on the one hand, to reduce the impact of chromatic aberrations on vision and, on the other hand, to reduce glare.

[0115] Finally, it will be noted that there is also a significant correlation between the decrease in macular pigment dPM density and, on the one hand, the decrease in visual acuity and contrast sensitivity and, on the other hand, the increase in the recovery time of visual performance after a rapid increase in luminous flux (Stringham et al., “Macular pigment and visual performance under glare conditions”. Optom. Vis. Sci. 2008, 85(2), p. 82-88).

[0116] There are known devices for measuring the density and spatial distribution of macular pigment inside the eye of a patient: the MPS II device (http: / / www.horus-pharma.com / index.php / fr / hi-tech / mpsii) from Horus Pharma, and the “VisuCam” device (http: / / www.zeiss.com / meditec / en_de / products—solutions / ophthalmology-optometry / retina / diagnostics / fundus-imaging / visucam500.html) from Zeiss.

[0117] The literature (Stringham et al, 2011: “Macular Pigment and Visual Performance in Glare: Benefits for Photostress Recovery, Disability Glare, and Visual Discomfort” Investigative Ophthalmology & Visual Science, September 2011, Vol.52, 7406-7415 and Stringham et al, 2008: Stringham JM, Hammond BR, “Macular pigment and visual performance under glare conditions11, Optom Vis Sci.

[0118] In particular, the lower the pigment density, the lower the light sensitivity threshold, therefore the greater the photosensitivity.

[0119] Pigment density is expressed by a value between 0 and 1, with the value 0 corresponding to a minimum density and the value 1 corresponding to a maximum density. The minimum and maximum densities are determined statistically, for example, after all the studies carried out on this subject.

[0120] The light sensitivity limit corresponds to the light intensity from Petition 870180146180, dated 10 / 30 / 2018, p. 38 / 95 26 / 68 of which visual discomfort is expressed by the wearer.

[0121] The wearer's visual comfort or discomfort is quantified by him with the help, for example, of a subjective comfort indicator ranging from 1 to 5 on a standardized rating scale, such as that described in more detail in example 5. Thus, the level of protection of the filter, i.e. its absorption and / or its reflectance, particularly in the blue wavelength range between 400 and 500 nm, must be higher when the macular pigment density is low.

[0122] In other words, in step b), the determined filter exhibits a transmission that is lower the lower the density of the macular pigment.

[0123] Furthermore, the recovery time of vision following a change in luminous flux involving a sudden and significant alteration in the intensity of this luminous flux is also linked to the macular pigment density of the affected eye.

[0124] The recovery time of vision is defined as the time taken by the eye to regain a predefined level of visual performance, either in absolute terms by a limit of acuity or a measure of contrast sensitivity, for example, or in relative terms by a percentage of the eye's performance before the change in luminous flux.

[0125] The time for vision recovery is defined here as the time it takes for the patient's eye to regain the initial visual performance it had before the change in light flux.

[0126] The lower the density of macular pigment in the eye of the carrier, the longer this recovery time is after a sudden and significant increase in intensity (Stringham JM, Hammond BR, “The glare hypothesis of macular pigment function”, Optom Vis Sci., September 2007, 84(9), 859-64, and “Macular Pigment and Visual Performance in Glare: Benefits for Photostress Recovery, Disability Glare, and Visual Discomfort”, Investigative Ophthalmology & Visual Science, September 2011, Vol.52, 7406-7415).

[0127] Similarly, the time it takes for vision to recover under conditions of dark adaptation is also correlated with the density value of Petition 870180146180, dated 10 / 30 / 2018, page 39 / 95 27 / 68 macular pigment. The lower the density of macular pigment, the longer the recovery time under dark conditions (Stringham JM & al., “Macular Pigment and Visual Performance in Low-Light Conditions”, Invest Ophthalmol Vis Sci., April 2015, 56(4), 2459-68).

[0128] Thus, in step a), the magnitude relating to the dynamic sensitivity of the carrier's eye to variations in luminous flux can be determined as the value of macular pigment density or as the value of the carrier's vision recovery time after a given variation in luminous flux.

[0129] According to a first modality, in step a), the macular pigment density of the eye of the recipient intended to receive the filter is measured.

[0130] The measurement of macular pigment concentration can be carried out using an objective physical autofluorescence measurement method such as that implemented in the Zeiss VisuCam device or using a subjective method called “heterochromic Flicker photometry” (Creuzot-Garcher et al., “Comparison of Two Methods to Measure Macular Pigment Optical Density in Healthy Subjects”, Retina 2014 IOVS, May 2014, Vol. 55, No. 5, pp. 2941-2947).

[0131] Consideration is given to either the average density of macular pigment (e.g. obtained by a “heterochromic flicker” type method) or the total distribution of macular pigment (e.g. obtained by a photographic method).

[0132] Depending on the density and spatial distribution of the macular pigment, the spectral response of the filter can be determined in step b), according to the method of the invention.

[0133] In particular, in step b), the absorption of the filter is determined to conform to the absorption curve of macular pigment as a function of wavelength, that is, identical to this curve, but with density varying according to the density of macular pigment measured in the individual.

[0134] Preferably, the filter is determined so that the system formed by the filter and the wearer's eye exhibits transmission close to that of a reference eye. By "reference eye" is meant a human eye in which the photoreceptors exhibit average sensitivity. Petition 870180146180, dated 10 / 30 / 2018, page 40 / 95 28 / 68 “close” means that the spectral transmission of the system formed by the filter and the wearer's eye is within a predefined margin around the spectral transmission of the reference eye. Typically, this margin can be plus or minus 15% around the spectral transmission of the reference eye.

[0135] In other words, the spectrum of the determined filter mimics that of the macular pigment spectrum.

[0136] The filter transmission is determined as a function of the macular pigment density value.

[0137] Indeed, the value of macular pigment density indicates the degree of protection to be achieved in order to preserve the retina.

[0138] More precisely, in step b), for a macular pigment density less than 0.2, the filter must greatly compensate for the protective function of the macular pigment. The absorption rate A^) of the filter is determined to be identical to that of the macular pigment with a maximum absorption rate of 40% for a wavelength of 460 nm.

[0139] For a macular pigment density between 0.2 and 0.6, the filter must provide a portion of the functions of the macular pigment because its density is not ideal. The filter's transmission is determined to compensate for the lack of absorption of the macular pigment in proportion to the loss: the absorption rate A^) of the filter is then defined by the relation A^) = (1-d) x ^λ), where d represents the macular pigment density measured in step a) and ^λ) is the absorption rate of the macular pigment at wavelength λ.

[0140] For a macular pigment density greater than 0.6, the filter then has a preventive function (e.g. DMLA).

[0141] The filter is then determined to enhance the action of the macular pigment: the absorption rate A^) of the filter is also defined by the relation: A^) = (1-d) x ^λ), where d represents the density of the macular pigment measured during the first operation and ^λ) is the absorption rate of the macular pigment at wavelength λ.

[0142] To adapt the filter and optimize the filter spectrum to be determined in step b), Petition 870180146180, dated 10 / 30 / 2018, page 41 / 95 29 / 68 it is also possible to take into account the retinal distribution of macular pigment and spectral characteristics of the characteristic luminous flux.

[0143] For example, it is possible to predict that the absorption rate of the filter will increase by an amount that is a function of the average density of the macular pigment and / or a function of the retinal distribution of this pigment (cf. Wolf-Schnurrbusch et al., op. cit.).

[0144] The distribution of macular pigment does not always follow a Gaussian function, centered on the fovea. It can have a different shape, in a so-called "Mexican hat" or "donut" shape. The filter must take into account the distribution of this macular pigment to better complete it.

[0145] It can also be predicted that the filter will exhibit a non-uniform absorption rate on its surface in order to adapt to the spatial distribution of the macular pigment.

[0146] Advantageously, the filter will be an adaptive filter whose absorption rate is not uniform and is adjusted in real time on its surface, for example controlled by an eye-monitoring device.

[0147] It is also possible to adapt the absorption rate of the filter to the spectral content of the characteristic luminous flux. This adaptation can be static or dynamic.

[0148] According to a second method, in step a), the macular pigment density of the eye of the recipient intended to receive the filter is measured and a vision recovery time for the recipient is deduced for a given variation of luminous flux by estimation, or the said vision recovery time of the recipient is measured directly.

[0149] In the first case, the recovery time estimate is, for example, performed based on a pre-determined database grouping the values ​​of this recovery time and the macular pigment density values ​​measured for different carriers.

[0150] The time it takes for the wearer's vision to recover can be determined experimentally by an adaptometry sensitivity test which will be described in detail later (see examples 2 and 4 for a negative variation of Petition 870180146180, dated 10 / 30 / 2018, page 42 / 95 30 / 68 lighting, similar tests can be considered for a positive variation in lighting).

[0151] In step b), the filter is determined to improve the wearer's recovery capabilities after such a change in luminous flux, that is, to decrease the wearer's vision recovery time.

[0152] For this purpose, in step b), it is planned to test, on the carrier, different filters presenting different transmission spectra, for example having a low transmission for a given different wavelength domain.

[0153] This wavelength domain, for example, centered on the wavelengths of maximum absorption of macular pigment.

[0154] Next, in step b), the wearer's vision recovery time is evaluated after a given change in light flux, for each filter tested, thanks to the aforementioned adaptometry sensitivity test.

[0155] The filter is determined by choosing one of the tested filters for which the recovery time measured in step b) is less than the recovery time determined in step a), or by determining the characteristics of the chosen filter based on the characteristics of tested filters for which the recovery time measured in step b) is less than the recovery time determined in step a).

[0156] Thus, with the filter, the wearer will lose less in visual performance and optimize their visual comfort during variations in luminous flux. EXAMPLE 2

[0157] In this example, a method for determining a filter according to the invention will be described, whereby, in step a), the aforementioned quantity relating to the dynamic sensitivity of the wearer's eye is determined as a function of one or more measured values ​​of the wearer's vision recovery time after a negative change in luminous flux intensity. For this purpose, the adaptometry sensitivity test is performed.

[0158] It is therefore planned, in stage a), to carry out the following sub-stages: a1) a step involving subjecting the bearer to the aforementioned variation in luminous flux, and Petition 870180146180, dated 10 / 30 / 2018, page 43 / 95 31 / 68 a2) a measurement step of a quantity related to the eye's adaptation to this variation in luminous flux, performed on the patient subjected to said variation in luminous flux.

[0159] In stage a1), the carrier is subjected to a luminous flux of predetermined non-zero intensity during a first exposure phase, then the carrier is subjected to a luminous flux of lower intensity, for example close to zero (darkness).

[0160] This transition from a significant luminous flux to a weaker luminous flux can, for example, simulate the transition from a bright outdoor environment to a much darker indoor environment or into a tunnel.

[0161] In step a2), a quantity characteristic of the visual performance of the eye or eyes of the wearer is measured.

[0162] More precisely, in stage a2), an average characteristic of the visual performance of the eye or eyes of the bearer is measured during a determined period of time after the start of the second phase and / or a darkness adaptation time corresponding to the bearer's vision recovery time required for said characteristic of their visual performance to reach a predetermined value.

[0163] This pre-determined value is preferably pre-determined based on its initial value before the change in luminous flux.

[0164] Next, the temporal evolution of a parameter representing the absolute retinal sensitivity of the carrier is traced, through an automated test in which a light stimulus of low initial luminance has its luminance reduced as the retina adapts. The automated program uses a stepwise strategy to track the evolution of the sensitivity threshold during the adaptation of the eyes to darkness.

[0165] False positive tests are randomly included during the course of the test and their results give an indication of the reliability of the measurement.

[0166] Here, more precisely, during step a1), the carrier is subjected to a visible white luminous flux, for example an electroluminescent diode spectrum. Petition 870180146180, dated 10 / 30 / 2018, p. 44 / 95 32 / 68 A neutral white LED produces an illumination at the wearer's eye level of between 500 and 1000 lux or a luminance of between 100 and 300 cd / m² for 5 minutes. The light is distributed in a Ganzfeld condition, i.e., across the entire field. During this first phase, the wearer fixes on a central point in their field of vision.

[0167] Alternatively, during step a1), the carrier is subjected to a light flash whose duration is less than or equal to 1 second.

[0168] In general, the luminance, spectrum and duration of the light stimulus during step a1) are adaptable, particularly to approximate realistic light exposure conditions as closely as possible.

[0169] Subsequently, the wearer is subjected to a darkness adaptation phase for 10 to 30 minutes.

[0170] During this second phase, the wearer is asked to press a bulb or a button as soon as he or she perceives a circular light stimulus of 10° angular extent presented in the center of a screen or dome placed in front of the wearer, appearing for 100 to 300 milliseconds every 3 seconds.

[0171] The stimulus luminance varies between 30 dB, corresponding to 0.318 cd / m2 and 80 dB, corresponding to 0.318.10Λ-5 cd / m2 in 1 dB steps. The 0 dB level is fixed at 318 cd / m2 (Goldmann perimeter reference). Luminance is expressed here in dB relative to this reference value, 0.318 cd / m2, corresponding to 10*log(0.318 / 318) = 30 dB.

[0172] When the carrier perceives the stimulus, the luminance of the stimulus decreases in 1 dB steps.

[0173] The luminance value in dB detected by the carrier at a given instant during the test constitutes the carrier's sensitivity value at that instant. It is reported in Figure 1 in order to trace the evolution of this sensitivity over time.

[0174] If the wearer does not perceive the stimulus, and therefore does not press the bulb or button during the time period, the luminance of the stimulus rises slightly. Throughout the duration of the dark adaptation phase, the patient's eyes are monitored by an infrared camera to ensure that he or she does not fall asleep or Petition 870180146180, dated 10 / 30 / 2018, page 45 / 95 33 / 68 that he does not maintain central fixation on the stimulus.

[0175] At the end of stage a2), the temporal evolution of the sensitivity S in dB detected by the wearer is plotted. This adaptometry curve, shown in figures 1 and 2, comprises two phases, of which only the first is shown in figure 1.

[0176] The first early phase corresponds to the activity of cone photoreceptors, involved in daytime vision. This phase lasts less than 6 minutes and is generally set at 5 minutes in the literature, see for example, “Comparison of AdaptRx and GoldmannWeekers Dark Adaptometers”, John G. Edwards1, David A. Quillen, MD2, Laura Walter2, D. Alfred Owens, Ph.D.3 and Gregory R. Jackson, Ph.D.2 ; “A short-duration dark adaptation protocol for the assessment of age-related maculopathy”, Gregory R. Jackson & John G. Edwards, J ocul biol dis inform (2008) 1:7-11 ; “Measurement Error of the AdaptRx Dark Adapter for Healthy Adults and AMD Patients”, Laura E. Walter, COA 1, David A. Quillen, MD1, John G. Edwards, MS, MBA2, D. Alfred Owens, Ph.D. 3 & Gregory R. Jackson, Ph.D.1. This first phase follows a logarithmic evolution.

[0177] It is followed by a slower phase, visible in figure 2, which reaches a significantly lower threshold and is due to the rods.

[0178] In figure 2, the first phase corresponds to the curve recorded between approximately 0 and 5 minutes, while the second phase corresponds to the curve recorded between 5 and 30 minutes. The curve shown in this figure is obtained here with the MonPack ONE commercial adaptometry device from Metrovision.

[0179] Cone adaptometry sensitivity analysis in the first 5 minutes of the dark phase is a very good indicator of the sensitivity of the wearer's eyes to a significant decrease in light flux over time.

[0180] The analysis consists of calculating the area under the sensitivity curve in dB up to 5 minutes (first phase of the adaptometry curve) to define the integrated sensitivity of the wearer's eye during these first 5 minutes (= 300 s) after passing into darkness (en dB).

[0181] Figure 1 shows the temporal evolution of sensitivity in dB of the eye of Petition 870180146180, dated 10 / 30 / 2018, page 46 / 95 34 / 68 carrier as a function of the time elapsed after passing into darkness in the first five minutes, that is, 300 seconds.

[0182] In this figure, two sets of sensitivity data are represented: a first set corresponds to the diamond-shaped points P1 measured for the carrier equipped with a reference filter whose visual transmission in the visible range between 380 and 780 nm is equal to 98%, equivalent to an absence of filter.

[0183] The second data set corresponds to the square-shaped P2 points, measured for the carrier equipped with a T1 filter. This T1 filter corresponds to the light state of a filter exhibiting photochromic properties. In this light state, the T1 filter blocks 40% of the blue-violet light between 400 and 455 nm and passes through the other wavelengths of the visible spectrum.

[0184] Its transmission is therefore 50% between 400 and 455 nm.

[0185] Its visual transmission across the entire visible spectrum is between 85 and 90% between 380-780 nm provided the filtering is selective.

[0186] The visual transmission of the filter is defined here as the transmission of the optical filter weighted by the reference solar illuminant D65 and the photopic sensitivity of the eye (ISO 13666: 1998 Standard ISO 8980-3).

[0187] The transmission of this filter as a function of wavelength is represented here in Figure 3. In this figure, curve CT1 corresponds to the transmission as a function of wavelength in the bright state of the filter, and curve CT2 corresponds to the transmission as a function of wavelength in the dark state of this filter. The latter curve is given as an example.

[0188] A logarithmic regression of each data set gives the C1 and C2 curves in figure 1.

[0189] The C1 curve with mathematical formula S = 3.4118Ln(t) + 31.748 corresponds to the measurements with the reference filter, with a correlation coefficient R2=0.8951.

[0190] The C2 curve with mathematical formula S = 5.2267Ln(t) + 29.459 corresponds to the measurements with the T1 filter, with a correlation coefficient R2=0.9679.

[0191] From these curves, it is possible to deduce the vision recovery time of the wearer equipped with each filter, defined here as the time required for the Petition 870180146180, dated 10 / 30 / 2018, p. 47 / 95 35 / 68 The wearer's eyes find a sensitivity equal to 50 dB, corresponding to the detection of a light stimulus of 0.318 x 10⁻² cd / m².

[0192] Here, the recovery time is equal to 210 seconds with the reference filter, and only 51 seconds with the T1 filter (figure 1).

[0193] An improvement in the recovery time At of 159 seconds is thus observed, a gain of 76% relative to the clear reference filter (equivalent to an absence of filter).

[0194] Furthermore, 300 seconds or 5 minutes after passing into darkness, the sensitivity of the wearer's eyes with the T1 filter is higher at AS=8 dB than the sensitivity of the wearer's eyes with the reference filter (figure 1).

[0195] In general, in step b), the lower the sensitivity in dB 5 minutes after going into darkness, or the longer the eye recovery time to reach a sensitivity of 50 dB, the more filtering the chosen filter must be, both in global visible transmission and in the blue spectral zone.

[0196] In other words, the filter transmission, whether averaged across the entire visible spectrum (between 380 and 780 nm), or averaged in the blue-violet spectral zone (between 400 and 455 nm), is lower the lower the sensitivity in dB 5 minutes after going into darkness, or the longer the eye recovery time to reach a sensitivity equal to 50 dB.

[0197] This example is particularly suitable for pseudophakic patients fitted with a white artificial lens after cataract surgery.

[0198] These carriers exhibit significantly greater uncomfortable glare than non-pseudophakic carriers. The applicant's work has shown in particular that the photosensitivity threshold of photosensitive pseudophakic carriers is on average 5 times lower than the photosensitivity threshold of healthy elderly individuals of the same age who are photosensitive, the threshold being determined under the same conditions in both cases. The photosensitivity threshold corresponds to the illumination or intensity value of Petition 870180146180, dated 10 / 30 / 2018, p. 48 / 95 36 / 68 maximum luminous flux that they can tolerate. In addition to having a significantly lower photosensitivity threshold than non-pseudophakic individuals, pseudophakic individuals have a lower first discomfort threshold to light, that is, corresponding to the maximum illumination or luminous flux intensity value that they can receive without discomfort.

[0199] They also exhibit a longer recovery time during luminous flux variations.

[0200] In particular, pseudophakic individuals are very sensitive to short wavelengths of visible light, blue-violet, because these are much more widely transmitted to the retina by the artificial lens than by the original lens, which filters out a good portion of the blue-violet.

[0201] For these carriers, a filter will be determined that blocks blue-violet wavelengths between 400 and 455 nm, at least 20%, preferably 40 to 50% of the luminous flux at these wavelengths, possibly associated with a photochromic filter to limit light discomfort in brightly lit outdoor environments. The transmission of this filter for wavelengths between 400 and 455 nm is therefore preferably less than 80%, preferably less than 60%, preferably less than 50%.

[0202] An example of a suitable filter for these carriers is, for example, an ophthalmic lens exhibiting photochromic or electrochromic properties, with a transmission of 55% of the wavelengths between 400 and 455 nm in the bright state (equivalent to the T1 filter mentioned earlier) and a transmission of 10% of these wavelengths in the darkened state (corresponding to a T2 filter, exhibiting, for example, a transmission similar to that of the CT2 curve in Figure 3.

[0203] A study conducted by the applicant on 16 pseudophakic patients fitted with this ophthalmic lens showed better dark adaptation in patients fitted with it compared to their dark adaptation without the ophthalmic lens (a case equivalent to the presence of the R reference filter mentioned earlier). Petition 870180146180, dated 10 / 30 / 2018, p. 49 / 95 37 / 68

[0204] In particular, a significant decrease in recovery time was demonstrated, i.e., a faster recovery from glare with the ophthalmic lens, with a decrease in this time of more than 90 seconds.

[0205] More precisely, the gross sensitivity at 5 minutes is on average 48 dB without the ophthalmic lens with a 95% confidence interval between 47 and 49 dB versus 51 dB with this lens with a 95% confidence interval between 50 and 52 dB.

[0206] With the lens in the T1 state, an average AS sensitivity difference of +2 dB is obtained compared to the absence of a lens, resulting in an average cone sensitivity gain of 6% at the end of 5 minutes.

[0207] These results are summarized in Table 1 below, where column R corresponds to the reference case without the ophthalmic lens and column T1 corresponds to the case where the wearer is equipped with the ophthalmic lens. Raw sensitivity in 5 min (dB) R T1 N 16 16 Mean 48 51 Median 48 51 Standard deviation 2.27 2.39 Min / Max 42 / 51 45 / 56 1st Quart. / 3rd Quart. 47 / 50 50 / 52 CI -95% / CI +95% 47 / 49 50 / 52

[0208] They are also represented graphically in Figure 4, in which the square point corresponds to the mean value, the rectangle surrounding it extends between the mean value plus or minus the standard deviation, and the bars extend between the mean value plus or minus the 95% confidence interval.

[0209] The recovery time required to achieve a sensitivity of 50 dB averages 274 seconds without the ophthalmic lens, with a 95% confidence interval (CI) ranging from 171 to 376 seconds, compared to 173 seconds with this lens. Petition 870180146180, dated 10 / 30 / 2018, p. 50 / 95 38 / 68 with a 95% CI ranging from 74 to 271 seconds. With the lens in the T1 state, there is a decrease in the average recovery time of 101 s compared to the situation without a lens, representing an average gain in sensitivity recovery time at 50 dB of 37%.

[0210] These results are summarized in Table 2 below, where column R corresponds to the reference case without the ophthalmic lens and column T1 corresponds to the case where the wearer is equipped with the ophthalmic lens. Table 2 Time at S=50 dB R T1 N 16 16 Average 274 173 Median 204 122 Min / Max 105 / 782 57 / 829 1st Quarter / 3rd Quarter 143 / 351 91 / 164 CI -95% / CI +95% 171 / 376 74 / 271

[0211] They are also represented graphically in Figure 5, in which the square point corresponds to the mean value, the rectangle surrounding it extends between the mean value plus or minus the standard deviation, and the bars extend between the mean value plus or minus the 95% confidence interval.

[0212] In general, if the carrier is pseudophakic, complains of increased photosensitivity after the operation, and has low dynamic sensitivity in darkness, a photochromic filter blocking blue-violet wavelengths is proposed. The photochromic characteristics of the filter are determined to have the best compromise between transmission and transition time to the light state. Several filters can be compared during the previously described protocol to determine the adapted transmission and photochromic characteristics, particularly as a function of the carrier's light exposure profile. EXAMPLE 3 Petition 870180146180, dated 10 / 30 / 2018, page 51 / 95 39 / 68

[0213] In this example, a method for determining a filter according to the invention will be described whereby, in step a), the said quantity relating to the dynamic sensitivity of the wearer's eye is relative to a dynamic characteristic of the pupil of the wearer's eye.

[0214] It is, for example, determined based on one or more measured values ​​of this dynamic characteristic of the pupil of the bearer's eye.

[0215] It is therefore planned, in stage a), to carry out the sub-stages a1) and a2) mentioned above.

[0216] In step a1), the carrier is subjected to a luminous flux of predetermined intensity, which may be zero (darkness condition) or non-zero during a first exposure phase (or darkness), then the carrier is subjected to a luminous flux of different intensity, namely of higher intensity.

[0217] In step a2), a quantity characteristic of the visual performance of the eye or eyes of the carrier is measured.

[0218] The dynamic characteristic of the pupil is namely related to its size, for example, its diameter, and more precisely to the variation of this size over time and according to the variation of luminous flux.

[0219] More precisely, in step a2), the variation in pupil size over time is determined during the aforementioned variation in luminous flux from step a1).

[0220] For this purpose, images of the wearer's eye are acquired during and after the variation in luminous flux, thanks to a high-frequency acquisition camera. This acquisition frequency is preferably greater than 100 Hertz.

[0221] The objective here is to evaluate pupil dynamics in response to light flux dynamics, which can vary in intensity, spectrum, source geometry, and temporal characteristics (flash and continuous).

[0222] Indeed, the pupil contracts or dilates depending on the intensity of the light flux incident on the wearer's eye. The size of the pupil, therefore, varies in response to the variation in light flux.

[0223] The characteristic size of the pupil may in particular be related to a Petition 870180146180, dated 10 / 30 / 2018, p. 52 / 95 40 / 68 pupil latency time, that is, the time it takes for the pupil to change size in response to a change in light flux.

[0224] This corresponds to an adaptation period for the wearer's eyes to darkness and light.

[0225] Depending on the wavelength of the light flux, the intensity of the temporal variations or the spatial variations of the light flux, the size of the pupil will not evolve in the same way over time.

[0226] The applicant's work, detailed below, showed that the faster the light signal is transmitted through the retina and up to the iris sphincter muscle, the shorter the latency time, the greater the discomfort for the wearer, regardless of age, luminance, and the spectral and temporal characteristics of the stimulus.

[0227] The characteristics of the variation in luminous flux are also determinants of the wearer's feeling of comfort and the temporal evolution of their pupillary diameter.

[0228] For example, in the case of young individuals under 40 years of age, the amplitude of pupillary constriction and / or the maintenance of this constriction after a light stimulus are more significant in the case of a light stimulus with a wavelength of 465 nm than for a wavelength of 619 nm, regardless of the photopic luminance and the duration of said stimulus. Indeed, under photopic light conditions, the less energetic wavelengths of blue between 460 and 510 nm activate ganglion cells with melanopsin that play a determining role in maintaining pupillary constriction. (Gamlin, McDougall et al., 2007, Human and macaque pupil responses driven by melanopsin-containing retinal ganglion cells, Vision Research, 47(7): 946-954).

[0229] In another example, for a light stimulus with a wavelength of 465 nm and the same stimulus duration, the higher the luminance, the more important it is to maintain the constriction, since an increasing number of ganglion cells with melanopsin (sensitive to these wavelengths of blue) are activated.

[0230] In another example, with fixed photopic luminance (for example between 100 Petition 870180146180, dated 10 / 30 / 2018, p. 53 / 95 41 / 68 and 400 Cd / m2) and for a light excitation wavelength of 465 nm, an increase in pupillary constriction duration is observed for increasing stimulus times between 1 ms and 500 ms. Beyond 500 ms and up to, for example, 1 s, pupillary constriction duration no longer increases. This result can be used advantageously to adjust the duration of the light stimulus, depending on the characteristics of the pupil used.

[0231] Thus, it is possible to determine for each carrier the transmission of the filter to be determined in stage b) as a function of the measured latency time of the carrier's pupil.

[0232] For this purpose, a reference limit value of the pupil latency time is defined for a given level of comfort from measurements carried out on numerous carriers or for a particular carrier. This reference limit value is used to determine the transmission of the filter in order to guarantee a pupil latency time of the carrier greater than the reference limit value.

[0233] For example, the reference limit value for comfort level 3 (on a scale of 0 to 5) is equal to 300 ms. If, with a filter whose transmission is 30%, after a change in light flux, the latency time of the wearer's pupil is measured as being equal to 220 ms, this means that this filter does not sufficiently protect the wearer from changes in light flux.

[0234] The average transmission of the filter is then reduced so that the carrier pupil latency time determined in step a) becomes greater than or equal to the reference limit value. The spectral characteristics of the filter, i.e., its transmission for different wavelength ranges, can also be optimized to prolong the pupil latency time.

[0235] According to the method described in this example 3, the filter is then determined based on the measured latency time of the wearer's eye pupil and the predetermined limit value of this time corresponding to a given level of visual comfort. Alternatively, the filter can be considered to be determined based on other dynamic characteristics of the eye's pupil, such as the speed of pupil recovery time following the stimulus or amplitude of constriction.

[0236] The determination of the reference limit value of the latency time can be Petition 870180146180, dated 10 / 30 / 2018, page 54 / 95 42 / 68 determined in the following manner during a preliminary calibration step.

[0237] This involves establishing a correlation between the measured latency time and the wearer's comfort level.

[0238] For each wearer in a group of wearers comprising a large number of wearers, for example, at least 10 wearers, steps a1) and a2) are performed with different variations of luminous flux. In step a2), information is also collected regarding the wearer's visual comfort following the variation in luminous flux from step a1). For example, the wearer is asked to note the level of comfort felt by the comfort indicator mentioned earlier.

[0239] For these different conditions, the person is asked to rate their comfort level between 0 and 5 according to the scale described in example 5. Then, a statistical analysis allows us to determine the correlation between comfort level and latency time.

[0240] More precisely, the measurements are taken according to the following protocol:

[0241] The measuring room is illuminated by a non-zero initial luminous flux. The wearer is fitted with wide-field test glasses with the minimum addition determined so that the wearer can perceive a clear luminous target of 33 cm.

[0242] The wearer is seated in a chair and places his chin on a dedicated chin rest. A dome emitting a homogeneous diffuse light is placed in front of him. The dome is switched off. The light in the measuring room is turned off and the wearer is placed in darkness for at least 1 minute, and ideally between 10 and 15 minutes. The wearer is instructed to fix on a luminous point whose luminance is equal to 1 candela per square meter (cd / m2) located in the center of the dome and his field of vision.

[0243] The dome emits stimuli: With each stimulus, it lights up for one second every ten seconds, and emits a luminous flux of determined wavelength and luminance corresponding to a type of stimulus.

[0244] The dome lights up four times per type of stimulus.

[0245] The luminances of the aforementioned stimuli correspond to intensities Petition 870180146180, dated 10 / 30 / 2018, p. 55 / 95 43 / 68 increasing scotopic luminous wavelengths, varying the sensitivity threshold of the carriers corresponding to a source luminance of approximately 0.00001 cd / m2, to a luminance of 0.01 cd / m2. The wavelengths are successively 660, 619, 525, 465, 414 nm for each luminance.

[0246] Between each stimulus, the patient is asked to rate their comfort level with the light stimulus on the aforementioned 5-level comfort scale.

[0247] The carrier is also subjected to photopic intensity stimuli for 5 wavelengths, for 1 second every 20 seconds, with increasing luminance from 1 cd / m2 to 300 cd / m2.

[0248] Between each stimulus, the subject is asked to rate their comfort level with the stimulus on the aforementioned 5-level comfort scale.

[0249] During a second measurement session, the wearer's eyes are initially adapted to the ambient light of the room. The dome emits a succession of photopic intensity stimuli for 5 wavelengths, for 1 second every 20 seconds, with increasing luminance from 1 cd / m2 to 300 cd / m2 in a step of 1 in photopic luminance logarithm.

[0250] Between each stimulus, the patient is asked to rate their comfort level with the light stimulus on the aforementioned 5-level comfort scale.

[0251] Then, the dome emits achromatic stimuli combining several wavelengths, for example 3 wavelengths: 465, 525 and 619 nm with a total luminance ranging from 1 cd / m2 to 1500 cd / m2.

[0252] Achromatic stimuli, for example, have a duration of one second every 20 seconds.

[0253] In parallel, for each stimulus the latency time of the subject's pupil is determined by analyzing images of this pupil recorded during the test, at high frequency.

[0254] In general, the analysis of these measures allowed the Applicant to show that the faster the light signal is transmitted through the retina and up to the iris sphincter muscle, the more significant the sensation of discomfort, and this Petition 870180146180, dated 10 / 30 / 2018, p. 56 / 95 44 / 68 regardless of age, luminance, spectral and temporal characteristics of the stimulus.

[0255] Advantageously, the analysis of the measures can also take into account the presence of different carrier subgroups within the group of carriers tested.

[0256] Figure 6 summarizes the results of these measurements. The latency time TL in milliseconds measured as a function of the level of the corresponding comfort indicator IndC evaluated by the wearers after each given variation in luminous flux.

[0257] Two subgroups of wearers are represented in this figure 6: a “young” population, aged between 18 and 40 years, forms the first subgroup whose data are represented by the circular points G1, and a “senior” population, aged over 60 years, forms the second subgroup whose data are represented by the square points G2.

[0258] The analysis of these data shows a correlation between latency time and the comfort indicator, represented by the linear regression curves F1 and F2 calculated for each carrier subgroup.

[0259] The F1 curve with the mathematical formula IndC = -3.839 + 0.0246*TL corresponds to the subgroup of “young” carriers.

[0260] The F2 curve with the mathematical formula IndC = -0.7665 + 0.0149*TL corresponds to the “senior” carrier subgroup.

[0261] Thus, it is possible from this correlation relationship to determine the reference limit value of the pupil latency time corresponding to any given comfort level (e.g., 4 or 3) and statistically valid for a subgroup of carriers.

[0262] Similarly, a reference limit value can be determined for the entire group of carriers. This reference limit value for the entire group of carriers can also be determined depending on the reference limit values ​​of each subgroup, for example, by considering the average of these values. EXAMPLE 4

[0263] In this example, in step a), the representative quantity of sensitivity Petition 870180146180, dated 10 / 30 / 2018, p. 57 / 95 45 / 68 The dynamic response of the wearer's eye to variations in luminous flux is linked to a dynamic sensitivity to glare in said wearer.

[0264] This is accomplished through steps a1) and a2) mentioned above.

[0265] In general, it is known that glare and the use of filters, such as solar filters, impact the vision and visual comfort of a wearer of ophthalmic lenses fitted with such filters.

[0266] Thanks to the method of determination of the invention, the spectral response of the filter is determined, which allows optimizing the vision and comfort of the wearer regardless of the variation in the characteristic luminous flux.

[0267] The method also allows customization of the spectral response of the filter, whether active or passive, depending on the carrier.

[0268] The method proposed here also takes into account the refraction of the wearer in order to have the best possible accuracy in this measurement, which is based on and integrates the visual performance of this wearer.

[0269] More precisely, the determination of the filter's spectral response here is based on the use of a dynamic "prescription cone".

[0270] In general, in step a) the aforementioned quantity representing the dynamic sensitivity of the wearer's eye is then relative to this prescribing cone. In step b), the filter is then determined in such a way that the luminous flux received by the wearer through this filter is situated, under the flux and flux variation conditions to which he is subjected, as frequently as possible within his prescribing cone.

[0271] The general principle of this prescription cone method is briefly described here before describing the filter determination method in more detail.

[0272] First, a static “prescription cone” is described taking into account the glare of the wearer by a static luminous flux. It will be seen below how this “prescription cone” is modified to take into account the dynamic aspects of comfort and visual performance linked to variations in luminous flux.

[0273] The method for determining the static “prescription cone” comprises the following steps. Petition 870180146180, dated 10 / 30 / 2018, page 58 / 95 46 / 68

[0274] In the first phase of the method, in step a1), the carrier is placed in a given luminous environment, and in step a2) the minimum transmission of the filter is determined while preserving comfort. For this transmission, its average can be calculated over a wavelength range, or it can depend on the wavelength. In the latter case, it is a determination of the transmission for a given wavelength.

[0275] This is illustrated in Figure 7, which shows the transmission of the T filter as a function of the illumination intensity E. Two curves are shown in this figure: a first curve 111A, the comfort threshold, corresponds to a minimum transmission of the filter that delimits two distinct zones: a comfort zone located above the first curve 111A in which the wearer is not disturbed by the luminous environment while performing their task; and a discomfort zone located below this first curve 111A in which the wearer is disturbed.

[0276] In a second phase of the method, in step a2), for the same lighting environment as in step a1), the maximum transmission of the filter is determined while maintaining optimized visual performance, for example: maintaining visual acuity or contrast sensitivity.

[0277] This is illustrated in figure 7 by the second visual performance threshold curve 111B corresponding to the maximum transmission of the filter which defines two distinct zones: a visual performance zone located below the second curve and a vision loss zone located above this second curve 111B.

[0278] In a third phase, the two previous approaches are combined to determine the prescription cone 111 (see figure 7).

[0279] This prescription cone corresponds to a filter transmission domain as a function of illumination intensity for which the visual performance and visual comfort of the wearer are guaranteed. This prescription cone thus allows the determination of the filter's optical characteristics (transmission) that preserve both the visual performance and visual comfort of the wearer for a given wide range of lighting environments.

[0280] Zone 111C in Figure 7 corresponds to a zone in which the carrier Petition 870180146180, dated 10 / 30 / 2018, page 59 / 95 47 / 68 experiences both a loss of visual performance and a loss of visual comfort.

[0281] The comfort and visual performance threshold curves 111A and 111B can be determined according to a descending or ascending method. For the descending method, the wearer starts with the darkest lens (for a given wavelength range), and decreases absorption / increases transmission of luminous flux to determine the thresholds (comfort and performance). The wearer then starts from a state where the retina is unsaturated.

[0282] For the ascending method, the wearer starts with the clearest lens (for a given spectrum or a given wavelength), and increases the transmission / decreases the absorption of the filter to determine the thresholds (comfort and performance). The wearer starts from a state where he or she may be dazzled: the retina is oversaturated with light.

[0283] To determine the static “prescription cone”, the wearer is placed in a luminous environment so that it is subjected to a controlled and parameterized characteristic luminous flux.

[0284] This characteristic luminous flux is characterized by: - a range of illumination intensity, for example between 0 and 20000 lux; - a range of visible wavelengths, for example between 400 nm and 680 nm; - Diffuse or localized lighting, directional or non-directional, defined for example by an orientation and diameter of the light source.

[0285] For the sake of simplification, only variations in lighting are considered in this example to explain the principle of implementing the method.

[0286] Measuring the sensitivity of the wearer's eye can be done by continuously varying the set of parameters mentioned above to more precisely characterize the wearer's sensitivity profile to glare.

[0287] It is also possible to repeat this measurement by studying the effect of the spectrum of Petition 870180146180, dated 10 / 30 / 2018, pp. 60 / 95 48 / 68 characteristic luminous flux in the carrier's sensitivity to light.

[0288] Next, the bearer looks at a target of previously defined size, shape, luminance, luminance contrast and spatial frequencies (or generally any target characterizing a visual capability, such as a colored target).

[0289] Preferably, the target is chosen based on the wearer's activity, that is, the desired vision requirement for the visual task under consideration. It may, for example, be linked to needs in terms of visual acuity, contrast sensitivity, color rendering accuracy, etc.

[0290] If necessary, the wearer uses a pair of ophthalmic lenses that allow for optimal correction of their refraction (sphere and cylinder).

[0291] He also uses a test filter placed in front of one or both of his eyes, the absorption rate and / or spectral response of this test filter being variable.

[0292] The measurement of the magnitude representative of the dynamic sensitivity of the wearer's eye to light flux is then carried out by means of a test filter placed in front of the wearer's eye, in which the absorption rate and / or spectral response is varied.

[0293] Regarding visual performance, the measurement stage begins with a test filter with a high absorption rate (darkened lens).

[0294] Indeed, in the case of a visual acuity or contrast measurement, this test filter penalizes vision: the wearer no longer recognizes the target.

[0295] The wearer is then asked to decrease the absorption rate of the filter (either with the help of an operator) until they find a satisfactory visual perception. This places us at the threshold of visual performance (change from “not seen” to “seen”). A psychophysical method can also be used to define this zone. Increasing the absorption rate of the filter determines this threshold, delimiting the zone that allows for non-degraded visual performance for the characteristic luminous flux considered.

[0296] This test is repeated for different light intensities of the flux. Petition 870180146180, dated 10 / 30 / 2018, p. 61 / 95 49 / 68 characteristic light source. This results in a curve similar to the second curve 111B in Figure 7.

[0297] Subsequently, the same measurement is performed, no longer with a vision test, but by asking the wearer to indicate the area from which the intensity of illumination of the characteristic luminous flux is harmful or triggers visual discomfort.

[0298] As before, a curve similar to the first curve 111A in figure 7 is then obtained.

[0299] This determines the prescription cone 111 corresponding to the zone in which visual performance is optimized for a given range of characteristic luminous flux illumination intensity and a range of filter absorption rate. Thanks to this prescription cone, the negative effect of a filter on the wearer's visual performance is also known.

[0300] This cone can also be defined as a function of the intensity of the luminous flux or the luminance of the source.

[0301] In this prescription zone 111, the optical characteristics of the filter such as absorption rate or spectral response are then determined so that the filter balances the comfort and visual performance of the wearer.

[0302] It is also possible to repeat these measurements by subjecting the wearer to a characteristic luminous flux characterized by different spectra modified by the filter or by the light source itself. In this way, the influence of the characteristic luminous flux spectrum on the wearer's eye's sensitivity to light is evaluated. This allows for guiding the choice of the optical characteristic(s) of the filter.

[0303] These measures can be repeated considering other criteria such as visual comfort, color perception, movement perception, etc.

[0304] This gives a spectral response range that allows you to maintain vision and comfort.

[0305] A dynamic “prescription cone” can also be determined in order to take into account the dynamic sensitivity of the wearer’s eye to variations in light flux.

[0306] Indeed, according to the carrier's exposure habits, their activity, Petition 870180146180, dated 10 / 30 / 2018, page 62 / 95 50 / 68 the lighting conditions he is confronted with (abrupt or progressive change in light), he will need different protection to position himself in his comfort zone.

[0307] For each defined comfort or performance threshold curve, the luminance delta tolerated by the individual is determined or, in other words, the dynamic comfort and performance zones 112A, 112B defined from various luminous flux variation conditions.

[0308] To characterize the dynamic sensitivity of the carrier, that is, its ability to adapt to variations in luminous flux, the prescription cone is performed with various parameters of luminous flux variations.

[0309] The bearer is subjected to a temporal variation of luminous flux: instantaneous changes in luminous intensity, or flash, in less than 1 s, linear progression of luminance in continuous light, in a given time, progression by luminance step, for example, a discrete increase in illumination intensity with a variation of 20% every 1 second. Other flux variations are possible, such as flux variation rates of 5% lux / sec (low speed), 25% / sec (medium speed) and 100% / sec (high speed).

[0310] A temporal change per step is felt by the wearer in a more aggressive way. Certain wearers have higher comfort thresholds when the luminance variation is progressive. The individual perceives less luminance contrast. This is what is represented in figure 8.

[0311] This figure 8 shows the variation of illumination in lux of the luminous flux as a function of time. The initial illumination of this luminous flux is E1. Two progressions are represented: a linear progression V1 between t1 and t3 and a stepwise progression V2 between t1 and t2.

[0312] The lighting comfort threshold value for the ES1 wearer for step-by-step progression V1 is lower than the ES2 comfort threshold value for linear progression V2. Furthermore, it is reached more quickly.

[0313] The comfort threshold for lighting therefore depends on the profile Petition 870180146180, dated 10 / 30 / 2018, pp. 63 / 95 51 / 68 temporal variation of luminous flux.

[0314] Consequently, in figure 7, a given transmission value Ti of the filter corresponds to two illumination limit values ​​ESi1 and ESi2 for the wearer's comfort limit.

[0315] It is also possible, for example, to determine in step b) an electrochromic filter that adapts the filter transmission to always guarantee a linear temporal change in retinal illumination if this type of change optimizes the visual performance of the wearer, that is, corresponds to a limit value of illumination for comfort and performance superior to that obtained for different types of change.

[0316] The temporal variation of luminous flux intensity depends on several parameters, namely the overall intensity variation AI, the duration of this variation D and the rate of variation, defined as the overall intensity variation divided by its duration.

[0317] Low flow rate variation ranges can be proposed, for example 5% lux / sec, medium ranges, for example 25% / sec and high ranges, for example 100% / sec.

[0318] By varying flow parameters (velocity, AI and D), dynamic zones 112A, 112B are delimited, corresponding to the carrier's flexibility in adapting to flow variations.

[0319] So, in step b), it can be considered that the rate of change of the filter transmission, that is, the rate of passage from the light state to the dark state or vice versa when the filter is electrochromic, or by default a photochromic function of the filter, for example the overall variation of transmission between the light and dark states and / or the duration of passage from the light state to the dark state, is adapted so that the change in illumination perceived by the carrier during the variation of the luminous flux illumination presents variation characteristics adapted to the carrier.

[0320] More precisely, in step b), a duration is determined that is necessary to go from one of the light and dark states to the other, which is shorter the Petition 870180146180, dated 10 / 30 / 2018, pp. 64 / 95 52 / 68 lower the wearer's adaptability.

[0321] Thus, in step b), a global transmission variation between the light and dark states of the filter is also determined, which is shorter the lower the carrier's adaptation flexibility.

[0322] It is also possible to determine a limiting rate of change of luminous flux ensuring the comfort of the wearer and to determine, in step b), the overall transmission variation of the filter and / or the duration of the transition from the light state to the darkened state so that the rate of change of luminous flux perceived by the wearer remains below the determined limiting rate.

[0323] Thus, for example, if the individual has a limiting rate of change in light intensity, illumination or luminance equal to a 25% increase in lux per second (25% / sec) and the variation in intensity, illumination or luminance to which he is subjected is 50% / sec, a filter with a transmission of 50% is determined. If the wearer is subjected to other variations in luminance, an active function will allow the filter's transmission to be adapted to each situation to achieve the target comfort limiting rate of change in intensity, luminance or illumination.

[0324] If the wearer has a high capacity to adapt to the dynamics of the luminous flux, differences will be obtained between extreme values ​​ESi1, ESi2 of comfort and visual performance limits (figure 7), and therefore wide dynamic zones 112A, 112B. Conversely, if the wearer has low dynamic sensitivity to flux variations, the dynamic zones 112A, 112B will be narrow.

[0325] It is thus possible to determine a carrier adaptation flexibility parameter, linked to the width of the dynamic zones 112A, 112B.

[0326] Determining the flexibility parameter for adapting the comfort limit and visual performance will determine the need for a specific prescription. If the value of this parameter is low, it will be essential to adapt the filter, adapting for example its transmission, so that the wearer remains in their dynamic comfort zone, delimited by the prescription cone 111 and the dynamic zones 112A, 112B in Figure 7, whatever the lighting environment with which they are exposed. Petition 870180146180, dated 10 / 30 / 2018, pp. 65 / 95 53 / 68 he is confronted.

[0327] Photochromic or electrochromic filters may be recommended. The transmission will be chosen so that the individual is always within their visual comfort and visual performance envelope for a given intensity and dynamic range.

[0328] Adaptability depends on several elements, including light intensity levels, the spectrum of the light source(s), the geometry of the light source (source size, intensity ratios between different sources, etc.) and its temporal component (flash, continuous light). All of these parameters can be considered to characterize the complete light sensitivity profile of the wearer.

[0329] Furthermore, note that the adaptation flexibility parameter may depend on the initial retinal state. It is therefore planned to characterize the dynamic zones for different initial retinal states, i.e., for different initial ambient light intensities.

[0330] An example is shown in Figure 9, which illustrates the temporal evolution of luminous flux illumination as a function of time.

[0331] Four experimental results are represented here: the carrier was placed in two different initial luminous fluxes EiA and EiB and for each initial illumination, this illumination was varied with two different speeds: curves V3 and V5 show the variation of the illumination with a first speed from the initial illuminations EiA and EiB, respectively, while curves V4 and V6 show the variation of the illumination with a second speed from the initial illuminations EiA and EiB, respectively.

[0332] Here, the illumination is increased until the wearer indicates visual discomfort. The maximum illumination value reached ESA3, ESA4, ESB5, ESB6 therefore constitutes the wearer's comfort limit for the corresponding luminous flux variation conditions. It is observed that these comfort limit values ​​differ according to the initial illumination value and the rate of variation thereof. Furthermore, the adaptation flexibility parameter defined here as the difference between the two Petition 870180146180, dated 10 / 30 / 2018, pp. 66 / 95 54 / 68 measured comfort limit values ​​for the same initial lighting value, differ according to this initial lighting value.

[0333] Thus, the adaptation flexibility parameter can constitute the quantity related to the dynamic sensitivity of the carrier determined in step a).

[0334] According to another example, in step a) instantaneous (abrupt) changes in lighting are carried out.

[0335] For this, the wearer is seated in front of a light dome that emits a homogeneous diffuse light. The individual is subjected to a given initial illumination (20, 200, 2000 and 4000 lux) for 90 seconds. Subsequently, a sudden change in illumination is applied, either positive or negative, to reach final illuminations of 500, 1000, 2000 and 4000 lux for a positive change and 20, 200, 1000 and 2000 lux for a negative change.

[0336] For each lighting situation, a comfort indicator value and a quantity related to visual performance are extracted. The quantity related to visual performance is, for example, determined by a visual acuity test with 10% contrast.

[0337] This analysis determines the evolution of the AIndC comfort indicator variation according to the AE lighting variation experienced by the wearer.

[0338] This evolution is, for example, represented by the graphs in figures 10 and 11 showing the data recorded for two different carriers.

[0339] It is then possible to determine a maximum variation of the comfort indicator allowed for the wearer, for example 2 points on the comfort rating scale. It is then possible to determine for each individual the critical lighting variation from which the individual will be in discomfort.

[0340] The magnitude relating to the dynamic sensitivity of the wearer's eyes determined in step a) can then correspond to this critical illumination variation. It is determined as a function of a wearer comfort variation threshold, here of 2 points.

[0341] In step b), an active solar device is then determined, comprising for example an electrochromic filter, to determine as a function of Petition 870180146180, dated 10 / 30 / 2018, pp. 67 / 95 55 / 68 ambient light intensity and analysis of variations in brightness experienced thanks to a camera integrated into this equipment, a transmission change that allows the wearer's eyes to receive constant illumination and variations in illumination, allowing them to maintain their visual comfort.

[0342] For example, the carrier whose data is represented in figure 10 is in a luminous environment with an intensity of 10000 lux and is using a filter with a transmission of 50%. The intensity received by the carrier's eyes is then 5000 lux.

[0343] This carrier will enter a zone of light where the intensity is 13000 lux.

[0344] The wearer will then receive 7500 lux if the filter transmission is maintained at 50%. This is equivalent to an increase in intensity of 1500 lux, which is associated with a decrease in the comfort indicator of 4 points according to the data in figure 10.

[0345] The filter proposed in step b) then allows limiting the intensity variation to 1000 lux, so that the variation in the comfort indicator is limited to a loss of 2 points.

[0346] The intensity received by the carrier after the variation must then be at most 6000 lux, which corresponds to a filter transmission of less than or equal to 40%.

[0347] During positive variations in light intensity, visual comfort and visual performance are affected. In the context of negative light variations, visual comfort is ideal; however, this decrease in brightness affects the individual's visual performance more. They have to adapt to a decrease in retinal illumination. The individual may lose, among other things, visual acuity and contrast sensitivity. A period of visual recovery is present until the retinal processes are regenerated.

[0348] A particular example of the method according to the invention relates to the characterization of this decrease in vision in connection with the determination of Petition 870180146180, dated 10 / 30 / 2018, pp. 68 / 95 56 / 68 dynamic zones of the prescription cone.

[0349] Thus, the method also includes a step to assess the impact of said luminous flux variation on the wearer’s visual performance.

[0350] After increasing the illumination from an initial value EiC to the comfort illumination limit ESC for different luminous flux variations, i.e., different variations in overall intensity and different durations of variations, a sharp decrease in illumination is applied to reach a minimum illumination value Emin of 13 lux.

[0351] Next, a visual acuity test is performed, defined as the ability to discriminate an optotype at the smallest angle, as described in Borish's Clinical Refraction (Butterworth-Heinemann; 2nd Edition, October 27, 2006).

[0352] The variation in illumination of the luminous flux during this test is represented in figure 12.

[0353] Depending on the comfort limit of the lighting, the amplitude of the reduction is different. A letter with 2 / 10 acuity and 10% contrast is affixed to the back of the dome when the light reduction is applied (time t0 = 0 in Figure 12). The time it takes the wearer to recover their vision of the letter is recorded (time tp in Figure 12). The letter is a Landolt C whose opening is randomly positioned. The wearer must indicate the direction of the opening. The response time in seconds is recorded for a correct identification of the letter's opening. This is another type of adaptometry sensitivity test.

[0354] Two examples of results are represented in figures 13 and 14. They show the correlation between the visual recovery time tp in seconds and the amplitude of the decrease in illumination suffered equal to the difference between the comfort illumination limit value ESC and the minimum illumination value Emin reached by two different individuals.

[0355] An improved relationship is established here between recovery time and illumination difference.

[0356] For figure 13, this improved relationship is written: tp =1.2814+ Petition 870180146180, dated 10 / 30 / 2018, pp. 69 / 95 57 / 68 0.0005*(ESC-Emin).

[0357] For figure 14, this improved relationship is written: tp = 8.313 0.0003*(ESC-Emin).

[0358] For the bearer whose data are represented in figure 13, the greater the magnitude of the reduction in illumination, the more time the individual needs to recover optimal vision.

[0359] For the carrier whose data is represented in figure 14, the carrier exhibits a virtually constant recovery time, regardless of the decrease in illumination intensity.

[0360] When the wearer is using optical equipment, the decrease in illumination experienced is linked both to the variation in incident luminous flux and to the presence of a filter placed in front of their eyes. In step b), the filter's transmission can then be adjusted to reduce the magnitude of the decrease in illumination experienced. In practice, this involves increasing this transmission.

[0361] In the case of the bearer of figure 13, an adaptive filter to the luminous environment (photochromic or electrochromic) is recommended, passing from the darkened state to the light state as quickly as possible. A transition time from the darkened state to the light state of 1 to 2 seconds is acceptable.

[0362] In the case of a photochromic filter, a filter is proposed that exhibits a rapid transition to the light state.

[0363] In the case of an electrochromic filter, it is proposed that the transmission limiting the decrease in illumination perceived by the wearer to 1500 lux is limited.

[0364] It may also be proposed that a filter be faded if the transmission set for the filter is not sufficient to optimize vision.

[0365] Such a filter thus exhibits a continuous preference variation of its transmission between an upper and a lower part situated in relation to its position in front of the wearer's eyes.

[0366] A filter having a dark tint on its upper part and a light tint on its lower part will allow, for example, the pavement and unevenness to be perceived more easily and avoid the risk of falls for older people. Petition 870180146180, dated 10 / 30 / 2018, p. 70 / 95 58 / 68 old.

[0367] Alternatively, during the stage of evaluating the impact of luminous flux variation on the wearer's visual performance, at least one measurement of one of the following quantities is taken on the wearer: - Contrast sensitivity: the visual system's ability to detect differences in luminance in elements of varying dimensions, whether static (spatial luminance contrast) or dynamic (temporal luminance contrast), see for example Sidorova et al., (“Functional acuity contrast sensitivity assessment in young and middle-aged healthy persons at the daytime with and without glare”, Acta Medica Lituanica, Vol. 21, No. - the field of vision that corresponds to the reach of space perceived by the wearer's eye when it is fixed and looking straight ahead (Borish's Clinical Refraction, op. cit.), - the perception of colors, that is, the visual perception of the spectral distribution of visible light. This sensation originates from the stimulation of specialized nerve cells called cones, located in the retina (op. cit.). - the perception of distances and depths. Depth perception is the visual ability to perceive the world in three dimensions and to discriminate the position of one object relative to another (op. cit.). - eyelid movement characterized by complete or partial closure of the eyelids, as well as eyelid tremors following muscle activity greater than that of the resting position. Muscle activity can be assessed by its electrical activity (electromyogram), see for example Murray et al. (“The ocular stress monitor: a new device for measuring discomfort glare”, Lighting Research and Technology, September 2002, 34:240). - the pupil diameter: the size of the circular opening located in the center of the iris. Petition 870180146180, dated 10 / 30 / 2018, p. 71 / 95 59 / 68 and allowing, through its contraction or dilation, to regulate the amount of light that enters the eye (cf. Alexandridis E., “The Pupil”. Springer; 1985), and other pupillary characteristics such as pupil shape, - visual discomfort on a discomfort scale: discomfort or unease experienced in relation to a sensation that follows intense light stimuli (Mainster et al., “Glare's causes, consequences, and clinical challenges after a century of ophthalmic study”. Am. J. Ophthalmol., 153 (4), p. 587-593. 2012), and - recovery time after glare: time required for the recovery of all or part of the functions that were degraded during the glare (Shieber, “Age and Glare Recovery Time for Low-Contrast Stimuli Effect of glare on reaction time for peripheral vision at mesopic adaptation”; Proceedings of the Human Factors and Ergonomics Society Annual Meeting, October 1994, 38:496-499).

[0368] Knowledge of the wearer's light exposure habits (past and future) combined with measurements of dark adaptation and photosensitivity threshold allows us to know the type of luminous flux variation to which the wearer is subjected, to know the limit value of intensity, luminance or comfort illumination of the wearer, to define the best filter, i.e., the best combination between spectral filtering, photochromic darkening level and return-to-light state time, so that the wearer is protected from glare and at the same time maintains good visual performance.

[0369] According to a second family of methods, the determination of the magnitude relating to the dynamic sensitivity of the bearer's eye is carried out from at least one piece of information measured or collected on the basis of a questionnaire relating to the bearer's light exposure habits. This family comprises example 5. EXAMPLE 5

[0370] In this example, step a) comprises the following substeps: a3) a step involving the carrier completing a questionnaire to assess the carrier's sensitivity to said flow variation Petition 870180146180, dated 10 / 30 / 2018, pp. 72 / 95 60 / 68 luminous, a4) a step of collecting the carrier's responses to the aforementioned questionnaire.

[0371] Then, in step a), the aforementioned quantity representing a dynamic sensitivity of the carrier's eye or both eyes to a variation in luminous flux is determined taking into account the responses to the questionnaire collected in step a3).

[0372] In practice, the carrier is given a questionnaire that allows the determination of the dynamic sensitivity of their eyes to variations in luminous flux.

[0373] A set of questions is proposed for which the wearer provides an indicator of their level of visual comfort or visual quality, for different variations of luminous flux, etc., and according to their activities, for example, driving, reading, sports activity, indoor or outdoor activity.

[0374] The questionnaire should preferably take into account three different time phases: with respect to a given time t of the carrier's reception, information is retrieved on: - the wearer's light exposure habits in a given environment before a given time t, - the analysis of the individual's sensitivity and adaptation to the dynamics of luminous flux over time t, - the lifestyle and lighting environment in which the carrier will develop.

[0375] The state of dynamic sensitivity of the retina at a time t will have an impact on the sensation of glare following a change in light intensity.

[0376] For example, if the individual is subject to chronic low-intensity exposures, their sensitivity to light will be more significant. Thus, the need for protection will be different, and a prescription for a filter with lower transmission will be advised.

[0377] The applicant's studies also showed that visual comfort following a change in the luminous flux received by the wearer is dependent on the following parameters: - an amplitude of the variation in the intensity of the light experienced, Petition 870180146180, dated 10 / 30 / 2018, pp. 73 / 95 61 / 68 - an initial intensity of luminous flux before the change in luminous flux.

[0378] More precisely, the higher the luminous flux intensity before the change and the higher the wearer's retinal illumination before this change, the less the wearer's visual comfort decreases after the luminous flux change.

[0379] In practice, the questionnaire allows the collection of information relating to different periods: past, present, future, on a variable scale: hours, weeks, months.

[0380] More precisely, it allows for the collection of information on the wearer's light exposure habits relating to: - characteristics of the light sources to which it is exposed: artificial light (e.g., LED or incandescent lamp) or natural light, diffuse or point light; - Exposure duration: instantaneous, short (a few seconds or minutes), long (a few hours), continuous or intermittent; - geographical location of the holder's address; - the climate of the bearer's geographical location and, in particular, the average duration of sunshine; - Activities performed / occupation: this information has implications for the duration of light exposure and the characteristics of the light sources depending on whether the activities take place indoors and / or outdoors: intensities, spectra, light variations.

[0381] For example, a person who works in a mine all day, in an enclosed environment, under low-intensity artificial light will accustom their retina to this low flux. Their sensitivity to light and variations in luminous flux will be more pronounced when confronted with a given bright outdoor environment. Conversely, a construction worker, working all day outdoors, under the same light level as before, will be less bothered. If the wearer's eyes are adapted to darkness, their sensitivity to a variation in luminous flux will be less. Petition 870180146180, dated 10 / 30 / 2018, pp. 74 / 95 62 / 68 will be more meaningful.

[0382] The questionnaire also allows for the collection of objective and subjective information about the person in question: - age, - general sensitivity to light, - sensitivity to light depending on lighting conditions (indoor, outdoor, night, ... - Sensitivity to variations in luminous flux: temporal or spatial variation of luminous flux intensity, temporal or spatial variation of the luminous flux spectrum, with positive variations indicating an increase in luminous flux, for example, a transition from a dark zone to a lit zone, and negative variations indicating a decrease in luminous flux, for example, a transition from a lit zone to a dark zone. - presence of visual or neurological pathology (affecting the individual's sensitivity to light), cataract surgery, and type of artificial lens implanted, for example, a yellow artificial lens, filtering blue or white light. - visual performance and visual comfort as expressed by the subjective rating scale described above, based on given lighting conditions, - Regular use of sunglasses: occasional, continuous, depending on lighting conditions, and assessment of the sunglasses being worn.

[0383] This questionnaire is completed either at the doctor's office, by the doctor or the patient, or at the patient's home by the doctor, on a regular basis.

[0384] In addition, this questionnaire can be completed in real time by the holder under given lighting conditions: the holder answers, for example, one or more questions that allow characterizing their visual comfort and / or visual performance at the present moment.

[0385] This could, for example, be an issue appearing on your smartphone or tablet. Petition 870180146180, dated 10 / 30 / 2018, pp. 75 / 95 63 / 68

[0386] In parallel, step a) may include a step measuring the luminous flux to which the wearer is usually subjected. This is carried out with the help of a luminous flux sensor that is independent or integrated into a pair of glasses or a connected object of the wearer, for example a smartphone, a tablet or a connected watch that collects the characteristics of the ambient luminous flux at that present moment. This sensor (spectrophotometer type) allows the collection of the characteristics of the luminous flux to which the wearer is subjected while filling out the questionnaire (namely intensity, spectrum, variation over time).

[0387] Alternatively to this questionnaire, it can be considered that information relating to the wearer's exposure habits, namely the characteristics of the light sources to which he or she is exposed and the duration of exposure, are directly measured by these sensors placed on the wearer, which perform measurements continuously or at pre-determined time intervals.

[0388] As an example, the question posed to the wearer may consist of a subjective assessment of their visual comfort and / or visual performance. The wearer may provide a subjective comfort indicator ranging from 1 to 5 on a standardized rating scale.

[0389] On this scale the different indicators are as follows: - Level “1”: unbearable level of visual comfort or very poor level of visual quality; - Level “2”: uncomfortable level of visual comfort or mediocre level of visual quality; - Level “3”: level of visual comfort is merely tolerable or level of visual quality is merely acceptable; - Level “4”: satisfactory level of visual comfort or visual quality; - Level “5”: Excellent level of visual comfort or visual quality.

[0390] Visual discomfort is defined as a subjective sensation of visual discomfort linked to the quantity, distribution, and quality of light received. The visual discomfort scale corresponds to a progressive gradation of the expression of visual discomfort according to different criteria (Gellatly and Weintraub, Petition 870180146180, dated 10 / 30 / 2018, p. 76 / 95 64 / 68 “User reconfigurations of the Boer classification for glass discomfort”, 1990).

[0391] It is therefore possible to determine, based on the responses, a dynamic sensitivity profile of the carrier to variations in luminous flux.

[0392] It is then possible to determine the magnitude relative to the dynamic sensitivity of the carrier in different ways.

[0393] According to a first method, one can consider having a database of filter wearers for whom the dynamic sensitivity of the eyes has been measured, for example according to a protocol such as described in one of the examples developed below and for whom the dynamic sensitivity profiles have been determined with an identical questionnaire.

[0394] The quantity relating to the dynamic sensitivity of the bearer's eyes is then determined from a reference quantity relating to the dynamic sensitivity of the eyes of bearers in the database having the same dynamic sensitivity profile, for example by matching this reference quantity.

[0395] In step b), the proposed filter is determined by example following the examples developed below.

[0396] According to a second method, the subjective comfort indicator expressed by the wearer for different light variation conditions and different activities can be considered a direct measure of their dynamic sensitivity. The magnitude relating to the wearer's dynamic sensitivity is then directly equal to this indicator or determined as a function of it.

[0397] Thus, for example, if the bearer expresses discomfort to a question about a given light variation, then the filter transmission level can be determined directly by the comfort indicator for this variation.

[0398] So, in step b), for example, for a comfort indicator of level “1” for a variation of current luminous flux intensity on the scale described above, a filter with a transmission of 10% is determined. Conversely, for a comfort indicator of level “5” (no discomfort, excellent comfort), a filter with a transmission of 90% is determined.

[0399] For a carrier who lives indoors during the week and goes out quite often Petition 870180146180, dated 10 / 30 / 2018, pp. 77 / 95 For outdoor use on weekends, given its significant sensitivity to light and variations in luminous flux, a filter with a transmission class 3 and / or polarized filter should be recommended.

[0400] For a carrier that frequently lives outdoors, without expressed discomfort during variations in luminous flux, a passive filter with a transmission that places it in one of classes 1 or 2 is determined in step b).

[0401] For a wearer who frequently lives outdoors, with significant discomfort expressed during variations in light flux, significant light sensitivity, and eventually a decrease in visual performance leading to vision loss after a change in light flux, an active preference filter is determined with a transmission that places him in class 3.

[0402] This is, for example, a filter exhibiting photochromic or electrochromic properties that allow the passage from a light state to a darkened state of the filter corresponding to two different levels of light transmission at least at one wavelength.

[0403] The filter determined here still exhibits rapid lightening, that is, a short transition time from the darkened state to the light state.

[0404] This filter will eventually be polarized to improve wearer comfort in high light conditions.

[0405] The need to use a color filter during an indoor activity can also be determined: in a classroom, at a workstation, when using screens.

[0406] In all cases, responses to the questionnaire may be weighted according to the person or according to the frequency with which he or she encounters the situation corresponding to the question.

[0407] For example, if a carrier spends more time outdoors than indoors, greater weight is given to questions about outdoor lighting conditions.

[0408] For this purpose, the bearer may be asked to associate, for each Petition 870180146180, dated 10 / 30 / 2018, p. 78 / 95 66 / 68 question, a coefficient giving the frequency with which the situation is found, for example a coefficient of 1 for a rare situation, a coefficient of 2 for an occasional situation, a coefficient of 3 for a frequent situation, and a coefficient of 4 for a very frequent situation.

[0409] In general, whichever method is used (examples 1 to 5), determining the filter according to one of the methods described may involve using a filter whose transmission varies spatially in the ophthalmic lens.

[0410] Indeed, light sources and variations in luminous flux may be located in privileged directions in the wearer's environment, or may be expected to have a filter exhibiting a different absorption rate and / or spectral response between the upper and lower parts of the ophthalmic lens.

[0411] On the one hand, the upper part is mainly used for outdoor activity where the luminous flux can be very high and where the spectrum of this flux is that of natural light.

[0412] On the other hand, the lower part is mainly used for indoor activity where the light flux is limited and where the spectrum of this flux is often that of artificial light.

[0413] Finally, note that the different methods from examples 1 to 5 can be combined to improve the determination of the optical filter.

[0414] Specifically, it is possible to combine the macular pigment method (example 2) with a questionnaire (example 5) in order to obtain a more accurate and complete light sensitivity profile of the bearer's eye.

[0415] In addition, the determination of the filter in step b) may take into account the characteristics of the usual or actual luminous flux (measured in real time) surrounding the carrier.

[0416] In particular, the determination of the filter in step b) may take into account the quantities and values ​​of parameters relating to the carrier determined in the table of step a), relating for example to the carrier's pupil, retinal illumination, static and dynamic sensitivity of the carrier to different conditions and variations of luminous flux given. Petition 870180146180, dated 10 / 30 / 2018, pp. 79 / 95 67 / 68

[0417] It also takes into account, as a preference, environmental parameter values ​​related to the characteristics of the luminous flux in the carrier's environment.

[0418] This is made possible notably by the integration of particularly spectrophotometric sensors into a pair of glasses comprising ophthalmic lenses with an active filter. These sensors measure the cumulative amount of light flux (illumination, luminance, etc.) received as a function of wavelength and record the evolution of illumination over time (day, weeks). This allows the active filter to be controlled and customized. The cumulative amounts per wavelength can be compared to control the change in filter transmission as a function of external illumination, but also of cumulative illumination over several days.

[0419] Finally, identifying the wearer's movements, for example thanks to other sensors such as an accelerometer or GPS, can make it possible to predict variations in incident luminous flux on the retina over time and anticipate the activation of the active filter. To anticipate temporal variations in the wearer's luminous flux, a photometric scene analysis will be defined by the integrated sensors to anticipate the activation of filter features according to the wearer's sensitivity profile.

[0420] These sensors (shape, size) are preferably integrated into the frame of the glasses in order to analyze the behavior of a wearer's pupils in a field of view > 30°, and explore the wearer's environment in more than 180° in the horizontal field and in more than 90° in the vertical field, at an analysis depth of at least 5 meters.

[0421] In the case of active filters described herein, the spectacles assembly may also integrate the computer processing unit programmed to perform the method according to the invention, in order to determine the characteristics of the electrochromic filter.

[0422] More generally, the quantities and / or parameters measured / determined in step a) may include a given real-time comfort indicator for the wearer to adapt the filter, or be determined automatically according to Petition 870180146180, dated 10 / 30 / 2018, pages 80 / 95 68 / 68 with objective analysis of the patient's behavior (analysis of the pupil, eyelid movements, signs of discomfort, head movement...).

[0423] This information can also be used to modify the filter selection rules used in step b) by learning. The recording of exposure habits and experiences will be carried out to continuously improve the algorithm in accordance with the wearer's lifestyle (continuous cycle). Consequently, the lenses initially provided to the wearer may be "standard", for example optimized for an average wearer, their personalization only occurring through learning. Petition 870180146180, dated 10 / 30 / 2018, pp. 81 / 95

Claims

1 / 6 CLAIMS 1. A method for determining a filter for an ophthalmic lens intended to be placed in front of the eye of a wearer, said filter being able to improve or maintain the visual comfort and / or visual performance of said wearer, said method comprising: a) a step of determining a representative quantity of the dynamic sensitivity of the wearer's eye or both eyes to a variation in luminous flux, and b) a step of determining at least one optical characteristic of said filter as a function of the representative quantity determined, said method being characterized in that - the filter exhibits photochromic or electrochromic properties that allow the filter to pass from a clear state to a darkened state corresponding to two different levels of light transmission of at least one wavelength,the optical characteristic being a transition time from one to another of the aforementioned light and dark states, - in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye or both eyes to a variation in light flux indicates an ability to adapt to a decrease or increase in the intensity of the light flux, and - in step b), the aforementioned at least one optical characteristic of the aforementioned filter is determined based on the ability to adapt to a decrease or increase in the intensity of the light flux such that the lower the ability to adapt, the shorter the transition time.

2. Method, according to claim 1, characterized in that the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux is representative of the evolution of visual comfort and / or visual performance of the wearer as a function of variations in luminous flux.

3. Method, according to any one of claims 1 to 2, Petition 870220122370, dated 12 / 27 / 2022, page 29 / 54 2 / 6 characterized in that in step b), an optical transmission of the filter of at least one wavelength is determined, in at least one spatial zone of this filter, which is lower the lower the representative magnitude of the dynamic sensitivity of the wearer's eye determined in step a) indicates that there is a low capacity for adaptation to a positive variation in the intensity of the luminous flux.

4. A method, according to any one of claims 1 to 3, characterized in that in step b), an optical transmission of the filter of at least one wavelength is determined, in at least one spatial zone of this filter, which is higher the more the representative magnitude of the dynamic sensitivity of the wearer's eye determined in step a) indicates that there is a low capacity for adaptation to a negative variation in the intensity of the luminous flux.

5. Method, according to any one of claims 3 to 4, characterized in that in step b), the optical transmission of the filter, of at least one wavelength, is determined in at least one spatial zone of this filter, taking into account the dynamic sensitivity of the carrier to positive and negative variations in the intensity of the luminous flux.

6. A method, according to any one of claims 1 to 5, characterized in that in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux may comprise a wearer comfort limit velocity for variations in luminous flux and / or a comfort limit value for the luminous intensity perceived by the wearer during variations in luminous flux and, in step b), the optical transmission of the filter, of at least one wavelength, in at least one spatial zone of this filter, is determined taking into account this wearer comfort limit velocity for variations in luminous flux and / or this comfort limit value for the luminous intensity perceived by the wearer during variations in luminous flux.

7. Method, according to any one of claims 1 to 6, characterized in that in step b), the transmission level of, Petition 870220122370, dated 12 / 27 / 2022, page 30 / 54 3 / 6, at least one of said light and dark states is determined as a function of the dynamic sensitivity of the carrier to variations in luminous flux.

8. A method, according to any one of claims 1 to 7, characterized in that the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to an adaptation time of the eye to variations in this luminous flux.

9. A method, according to any one of claims 1 to 8, characterized in that in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to a comfort limit speed and / or a variation in the wearer's comfort limit for variations in luminous flux and, in step b), the aforementioned transition time between the light and dark states is determined as a function of this comfort limit speed and / or a variation in the comfort limit.

10. Method, according to any one of claims 1 to 9, characterized in that in step a), the aforementioned quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux corresponds to a comfort limit value for the luminous intensity perceived by the wearer during the variation in luminous flux and, in step b), the transmission level of the light and / or darkened state of the filter is determined as a function of this comfort limit value.

11. Method, according to any one of claims 1 to 10, characterized in that the said quantity representing the dynamic sensitivity of the wearer's eye to variations in luminous flux is determined taking into account at least one of the following parameters: - a parameter relating to the wearer's past, present and / or future habits of exposure to light, - a parameter relating to the wearer's static sensitivity to luminous flux, - a parameter relating to the amplitude of the temporal and / or spatial variation of the intensity and / or spectrum of the luminous flux, - a subjective parameter relating to the wearer's visual performance. Petition 870220122370, dated 12 / 27 / 2022, p.31 / 54 4 / 6 for given light conditions and / or light variations, - a subjective parameter related to visual comfort for given light conditions and / or light variations, - a parameter related to the wearer's age, - a parameter related to the use of sunglasses, - a parameter related to the intraocular diffusion coefficient of the wearer's eye, - a parameter related to the density and / or distribution of macular pigment in the wearer's eye, - a parameter related to the retina's ability to adapt to light or darkness, - a parameter related to the dynamics of pupillary response to light variation and / or another pupillary characteristic, - a parameter related to a visual pathology or possible ocular anomaly of the wearer, - a parameter related to a limit of variation in visual comfort and / or visual performance expressed or measured.

12. Method, according to any one of claims 1 to 11, characterized in that step a) comprises a step of measuring the dynamic luminous flux to which the carrier is usually subjected.

13. A method, according to any one of claims 1 to 12, characterized in that said step a) of determining the quantity representative of the dynamic sensitivity of the wearer's eye to variation in luminous flux comprises: a1) a step of subjecting the wearer to said variation in luminous flux, and a2) a step of measuring a quantity relating to the adaptation of the eye to this variation in luminous flux, performed on the wearer subjected to said variation in luminous flux.

14. Method, according to claim 13, characterized by Petition 870220122370, dated 12 / 27 / 2022, page 32 / 54 5 / 6 in that in step a1), the wearer is subjected to a predetermined luminous flux during a first exposure phase, then the wearer is placed in darkness during a second darkness phase and, in step a2), an average sensitivity is measured during a determined period of time after the start of the second phase and / or a darkness adaptation time corresponding to the time required for the wearer's eye sensitivity to light to reach a predetermined sensitivity value.

15. Method, according to any one of claims 13 or 14, characterized in that in step a2), the variation in pupil size over time is determined during at least the aforementioned variation in luminous flux of step a1).

16. Method, according to any one of claims 1 to 15, characterized in that in step a), the variation of luminous flux comprises at least: - a temporal and / or spatial variation of an intensity of said luminous flux and / or - a temporal and / or spatial variation of a spectrum of said luminous flux and / or - a spatial variation of a spatial distribution of said luminous flux and / or - a spatial variation of an angular distribution of said luminous flux.

17. Method, according to claim 16, characterized in that in step a), the carrier is subjected to different temporal variations of luminous flux intensity, presenting different given temporal variation profiles, and / or different given temporal variation rates, and / or different given variation amplitudes, and / or different given initial and / or final luminous flux intensities.

18. Method, according to any one of claims 1 to 17, characterized in that a further step is performed to determine a representative quantity of the environment in which the filter is used by the carrier and the said optical characteristic of said filter is determined taking into account this representative quantity of the environment.

19. Method according to any one of claims 1 to 18, characterized in that in step a), the aforementioned quantity representing the sensitivity of the wearer's eye to variation in luminous flux corresponds to a limiting comfort velocity and / or a limiting comfort variation of the wearer for variation in light flux and, in step b), a difference in transmission between the light and dark states and / or a speed of passage from one to the next of the light and dark states is further determined depending on this limiting comfort velocity and / or a limiting comfort variation.

20. Method, according to any one of claims 1 to 19, characterized in that in step b), the said transition time from one to the other of said light and dark states is determined to be lower the more the sensitivity of the eye or both eyes of the wearer determined in step a) indicates low adaptive capacity. Petition 870220122370, dated 12 / 27 / 2022, p. 34 / 54

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