Method and apparatus for determining personalized near vision index

Abstract

This method for determining a personalized near vision index of an individual comprises: measuring (10) at least one parameter relating to an adjustment of the individual; determining (12) a binocular vision model representing the vision of the individual; a personalized near vision index is obtained (14), comprising binocular vision efforts of the individual at the time of near vision, evaluated from the measured at least one parameter relating to the adjustment and the determined binocular vision model.

Description

Technical Field

[0001] The present invention relates to a method and a device for determining a personalized near vision index. Background of the Invention

[0003] In the early stages of presbyopia, patients experience discomfort when looking at close objects: they experience visual fatigue and / or decreased near visual performance.

[0004] However, they are often unaware that the discomfort is caused by their vision and are unaware that there are optical correction solutions. Even if they have heard about presbyopia, they are not concerned.

[0005] Furthermore, most patients use workarounds to compensate for near vision problems and wait until the point where they are no longer willing to endure before being fitted with ophthalmic lenses that correct for near vision (ie, down add).

[0006] On the other hand, recent consumer research on this issue shows that consumers want to be in the driver's seat of managing their vision. Additionally, practitioners do not know when they should start eye exams for near vision or recommend devices for visual comfort.

[0007] Document US2021 / 085173 A1 discloses a method and system for measuring binocular alignment.

[0008] Document US 2012 / 019775 A1 discloses a training method for accommodation and vergence systems, and a multifocal lens for use in the method.

[0009] Document US2021 / 290053 A1 discloses an apparatus, system and method for visual assessment and treatment.

[0010] In the prior art, it is possible to measure an individual's near vision performance, but there is no method for evaluating the visual comfort of an individual who is not wearing any visual device when seeing near objects.

[0011] Therefore, consumers and practitioners need to characterize the visual comfort of the early stages of presbyopia and the introduction of ophthalmic lens correction in a way that is easily understood by the wearer. Summary of the invention

[0012] The purpose of the present disclosure is to overcome the above-mentioned shortcomings of the prior art.

[0013] To this end, the present disclosure provides a method for determining an individual's personalized near vision index, which is significant in that the method comprises:

[0014] measuring at least one parameter associated with regulation of the individual;

[0015] determining a binocular vision model that represents the individual's vision;

[0016] A personalized near vision index is obtained, the personalized near vision index comprising the individual's binocular visual effort when near vision, the binocular visual effort being assessed based on the measured at least one parameter related to accommodation and the determined binocular vision model.

[0017] Therefore, the method according to the present disclosure makes it possible to associate a personalized near vision index with a vision correction recommendation, thereby, on the one hand, allowing the consumer to be aware of presbyopia, its evolution and the available optical solutions, understand presbyopia and take the lead in choosing an optical solution, and on the other hand, allowing the eye care professional (ECP) to objectively evaluate the near vision in the optometry office and decide whether to start a near vision examination of the eyes, as well as to help the consumer with a visual needs analysis in the store and guide him or her to find the best solution.

[0018] That is, the proposed personalized near vision index is based on a number of criteria, which will be described in detail below, giving an indication of where each individual is in terms of visual comfort or effort when seeing near, where he or she might benefit from an optically corrective solution, and allowing for the prediction of the evolution of visual comfort.

[0019] The main result of the Personalized Near Vision Index is similar to the accommodation curve in the health journal to locate and track the evolution of an individual's near vision, but the difference is that it does not only consider pure accommodation ability.

[0020] In an embodiment, the at least one parameter related to accommodation is taken from the group consisting of accommodation amplitude, full accommodation response from far to near vision, accommodation near point, accommodation far point, dark focus and micro-fluctuation amplitude.

[0021] In an embodiment, the measuring further comprises measuring binocular vision of the individual, including measuring at least one parameter among heterophoria, fusional reserve, accommodative convergence / accommodative ratio, convergence accommodation / convergence ratio, other accommodation-convergence linkages, and other convergence abilities.

[0022] In an embodiment, the binocular vision model includes models of accommodation, convergence, and accommodation-convergence linkage based on blur and disparity.

[0023] In an embodiment, binocular vision effort includes motor effort, which is the brain effort an individual makes to accommodate and converge, and processing effort, which is the brain effort an individual makes to compensate for blur and parallax.

[0024] In an embodiment, binocular vision effort is the sum of motor effort and processing effort, and the motor effort E is t for accommodation and convergence, respectively. m and processing effort E p It is given by the following formula:

[0025] E m =k m (RX) 2

[0026] E p =k p (SR) 2

[0027] Among them, for regulation and convergence respectively:

[0028] k m and k p is the predetermined coefficient,

[0029] S stands for stimulation.

[0030] R is the total reaction,

[0031] X is the reflex response for accommodation and convergence accordingly.

[0032] In an embodiment, the individual wears an ophthalmic correction, and the method further comprises using a personalized near vision index to assess the individual's visual comfort with the ophthalmic correction.

[0033] In an embodiment, the method further comprises using the personalized near vision index to recommend an ophthalmic correction that provides optimal visual comfort for the individual.

[0034] In an embodiment, the personalized near vision index adopts discrete values.

[0035] In another embodiment, the personalized near vision index is a continuous scale.

[0036] In an embodiment, the personalized near vision index further includes a vertical parallax effort.

[0037] In an embodiment, the vertical parallax effort is given by the following formula:

[0038] (vdisp / maxdisparityVer) 2

[0039] Among them, vdisp is the vertical disparity, maxdisparityVer is the maximum vertical disparity, and the maximum vertical disparity is equal to the vertical fusion reserve.

[0040] For the same purpose as above, the present disclosure also provides a device for determining an individual's personalized near vision index, which is notable in that the device comprises:

[0041] means for measuring at least one parameter related to regulation of the individual;

[0042] means for determining a binocular vision model representing the vision of the individual;

[0043] A device for obtaining a personalized near vision index, which includes an individual's binocular visual effort when seeing near, and the obtaining device is adapted to evaluate the binocular visual effort based on at least one measured parameter related to accommodation and a binocular vision model, wherein the at least one measured parameter related to accommodation is provided by a device for measuring at least one parameter related to accommodation, and the binocular vision model is provided by a device for determining a binocular vision model.

[0044] For the same purpose as above, the present disclosure also provides a computer program product, which is notable in that the computer program product includes one or more instruction sequences, which can be accessed by a processor and when executed by the processor, cause the processor to implement a method for determining an individual's personalized near vision index, and the processor is configured to:

[0045] obtaining at least one measured parameter related to regulation of the individual;

[0046] determining a binocular vision model that represents the individual's vision;

[0047] A personalized near vision index is obtained, the personalized near vision index comprising the individual's binocular visual effort when near vision, the binocular visual effort being assessed based on the measured at least one parameter related to accommodation and the determined binocular vision model.

[0048] For the same purpose as above, the present disclosure further provides a non-transitory information storage medium, which is notable in that the non-transitory information storage medium stores one or more instruction sequences, which can be accessed by a processor and when executed by the processor, cause the processor to implement a method for determining a personalized near vision index for an individual, and the processor is configured to:

[0049] obtaining at least one measured parameter related to regulation of the individual;

[0050] determining a binocular vision model that represents the individual's vision;

[0051] A personalized near vision index is obtained, the personalized near vision index comprising the individual's binocular visual effort when near vision, the binocular visual effort being assessed based on the measured at least one parameter related to accommodation and the determined binocular vision model.

[0052] Since the specific features and advantages of the device, computer program product and information storage medium are similar to those of the method, they are not repeated here.

[0053] The computer program product is advantageously configured for performing the method in any of its execution modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] For a more complete understanding of the description provided herein and the advantages thereof, reference is now made to the following brief description taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0055] Figure 1 is a flow chart illustrating the steps of a method according to the present disclosure in a particular embodiment.

[0056] Figure 2 is a schematic diagram of an example of modification of accommodation and vergence stimuli used in certain embodiments according to the methods of the present disclosure by an ophthalmic lens.

[0057] Figure 3 is a graph showing the near visual effort according to the required downlight addition when the individual under consideration is not wearing any ophthalmic correction, which visual effort is evaluated according to the method of the present disclosure in a specific embodiment.

[0058] Figure 4 is a graph showing the near visual effort according to the required downlight addition when the individual under consideration is wearing an ophthalmic correction, which visual effort is evaluated according to the method of the present disclosure in a specific embodiment. DETAILED DESCRIPTION

[0059] In the following description, the drawings are not necessarily drawn to scale, and certain features may be shown in generalized or schematic form for the purpose of clarity and simplicity or for information purposes. In addition, although the manufacture and use of different embodiments are discussed in detail below, it should be understood that many inventive concepts that can be embodied in a variety of contexts are provided as described herein. The embodiments discussed herein are merely representative and do not limit the scope of the invention. It is also apparent to those skilled in the art that all technical features defined relative to the method can be transposed to the device alone or in combination, and conversely, all technical features relative to the device can be transposed to the method alone or in combination.

[0060] The terms "comprise" (and any grammatical variations thereof, such as "comprises" and "comprising"), "have" (and any grammatical variations thereof, such as "has" and "having"), "contain" (and any grammatical variations thereof, such as "contains" and "containing"), and "include" (and any grammatical variations thereof, such as "includes" and "including") are open-ended linking verbs. They are used to specify the presence of stated features, integers, steps or components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps or components or groups thereof. Thus, a method or step in a method that "comprises", "has", "contains" or "includes" one or more steps or elements possesses those one or more steps or elements, but is not limited to only those one or more steps or elements.

[0061] Figure 1 The steps of a method for determining a personalized near vision index for an individual according to the present disclosure in a particular embodiment are shown.

[0062] A first step 10 of the method comprises measuring at least one parameter related to regulation of the individual.

[0063] The at least one parameter related to accommodation may be one or more of the following: accommodation amplitude, full accommodation response from far vision to near vision, accommodation near point, accommodation far point, dark focus, and micro-fluctuation amplitude.

[0064] Optionally, in step 10, in addition to measuring at least one parameter related to accommodation, the method may further include measuring binocular vision of the individual. This includes measuring one or more of the following parameters: heterophoria, fusion reserve, accommodation convergence / accommodation ratio, convergence accommodation / convergence ratio, other accommodation-convergence linkages, and other convergence abilities.

[0065] In fact, the accommodative amplitude is a physiological parameter that undeniably evolves with age and is mainly used as a reference for explaining near vision problems. However, it is not enough to manage near vision problems with reference to age. In order to fully characterize the accommodative response, many other parameters can be evaluated, such as dark focus (also called resting or tonic accommodation), accommodative gain characterizing lead and lag, coupling gain with convergence (ACA ratio or accommodation-convergence / accommodation ratio, and CAC ratio or convergence-accommodation / convergence ratio), near point accommodation, etc. In addition, the accommodative response may be affected by binocular vision problems (phoria, fusion reserve, etc.), pupil diameter, etc.

[0066] like Figure 1 As shown, the next step 12 comprises determining a binocular vision model representing the vision of the individual.

[0067] By way of non-limiting example, binocular vision models may include models of accommodation, convergence, accommodation-convergence linkage based on blur and disparity. The proposed model preferentially attempts to maintain consistent known relationships with age and brightness.

[0068] After step 12, step 14 is performed, which includes obtaining a personalized near vision index. The personalized near vision index includes the binocular visual effort of the individual when near vision. The binocular visual effort is evaluated based on at least one parameter related to accommodation measured in step 10 and the binocular vision model determined in step 12.

[0069] The personalized near vision index may take discrete values ​​(eg, two basic values ​​of "comfortable" and "uncomfortable", six values ​​from "very uncomfortable" to "very comfortable", etc.), or may be a continuous scale that is not necessarily linear.

[0070] By way of non-limiting example, binocular vision effort can include motor effort and processing effort. Motor effort is the brain effort an individual makes to accommodate and converge. Processing effort is the brain effort an individual makes to compensate for blur and parallax.

[0071] By way of non-limiting example, binocular visual effort may be the sum of motor effort and processing effort. Accordingly, for accommodation and convergence, motor effort E m and processing effort E p It can be given by the following formula:

[0072] E m =k m (RX) 2

[0073] E p =k p (SR) 2

[0074] Among them, for regulation and convergence respectively:

[0075] k m and k p is the predetermined coefficient,

[0076] S stands for stimulation.

[0077] R is the total reaction,

[0078] X is the reflex response for accommodation and convergence accordingly.

[0079] In certain embodiments, k m = k(1-G) and k p =kG x , where G is the adjustment gain and convergence gain respectively, Gx =G(1-dX / dR), where dX / dR is the derivative of X with respect to R and k is a normalization factor.

[0080] In another specific embodiment, binocular visual effort can be expressed differently. Motor effort can be related to the distance from the resting point (AR-dkF), where AR is the accommodation response and dkF is the dark focus. Processing effort can be related to the distance from the stimulus (AS-AR), where AS is the accommodation stimulus. The accommodation-convergence response of the visual system can correspond to the minimum effort for a given stimulus. This means that at the effective response of the visual system, the derivative of the effort model to the response should be zero. This would imply a quadratic effort model for a linear response model.

[0081] For monocular accommodation response, AR = AG.AS + (1-AG)dkF, where AG is the accommodation gain, E p =k p .(AS-AR) 2 , where typically k p =1 and E m =k m .(AR-dkF) 2 , where typically k m =(1-AG) / AG.

[0082] Then, the monocular visual effort is ([(1-AG) / AG](AR-dkF) 2 +(AS-AR) 2 ) / Tol_blur, where Tol_blur is a normalization coefficient. For example, Tol_blur = k max .DoF.(PPA-PRA+DoF), where k max is a predetermined coefficient expressing the sensitivity to blur depending on the individual and visual conditions, DoF is the depth of focus or depth of field, PPA is the near point of accommodation, and PRA is the far point of accommodation.

[0083] The binocular accommodation effort model can be defined as the average monocular effort using either a linear weight or a quadratic weight d for the dominant eye.

[0084] Using linear weights:

[0085] AS 双眼 =((1+d)AS 右眼 +(1-d)AS 左眼 ) / 2.

[0086] Using quadratic weights:

[0087]

[0088] If there is no dominant eye, d = 0, if the right eye is dominant, d = 1, if the left eye is dominant, d = -1. As a variant, d can take any value between -1 and +1 to simulate non-binary dominance, i.e. a continuous degree of dominance.

[0089] The binocular model can be derived from the monocular model, and the corresponding relationship is as follows:

[0090] AG corresponds to AG-ACA.CAC, where ACA is convergence adjustment and CAC is convergence adjustment;

[0091] dkF corresponds to dkF + CAC (VS - dkV), where VS is the vergence stimulus and dkV is the dark vergence;

[0092] AR corresponds to AR+VR, where VR is a convergence reaction.

[0093] Therefore, binocular visual effort can be given by the following formula:

[0094] [[(1-AG) / (AG-ACA.CAC)].[AR-[dkF+CAC(VS-dkV)]] 2 +(AS-AR) 2 ] / Tol_blur +[[(1-VG) / (VG-ACA.CAC)].[VR-[dkV+ACA(AS-dkF)]] 2 +(VS-VR) 2 ] / Tol_cv

[0095] where Tol_blur=kmax.DoF.(PPA-PRA+kmax.DoF) and Tol_cv=PaRHor.(PPC-PRC+PaRHor) are normalization coefficients, where kmax=Δfr / Δblur, where Δfr represents the fusion reserve and Δblur is the blur limit (typically kmax is approximately equal to 1.41, also depending on age, and Δblur is approximately equal to 30 diopters),

[0096] And among them:

[0097] AG is the adjustment gain,

[0098] ACA is the regulatory convergence,

[0099] CAC is convergence adjustment.

[0100] AR is the regulatory response (effective regulatory plan proximity),

[0101] VR is the vergence response (effective vergence plan proximity),

[0102] VG is the convergence gain,

[0103] dkF is the dark focus,

[0104] VS is the vergence stimulus (the proximity of the horizontal or optimal fixation intersection),

[0105] dkV is dark convergence and dispersion,

[0106] AS is the accommodation stimulus (the proximity of the object image seen through the lens, i.e. the focal error calculated along the gaze direction),

[0107] PRA is the accommodative far point (objective refractive error), which is zero if the individual is emmetropic.

[0108] PPA is the near point of adjustment (PPA = ObjAA + PRA),

[0109] DoF is the depth of focus, DoF = (DoF (PRA) + DoF (PPA)) / 2, DoF = max {1, (0.11 + 0.03 × age) / (0.536 + 0.006 × age)}. ObjDoF, where ObjDoF = 1.5-0.1125 [Dpup (0) + Dpup (PPA-PRA)] / 2, Dpup is the pupil diameter,

[0110] PaRHor is the horizontal Pan radius, PaRHor = 6 + SF / 4 + 3.75Ecc (in arc minutes), where SF is the spatial frequency, Ecc is the retinal eccentricity, and PaRHor in diopters is equal to the product of PaRHor in arc minutes and π / (60.180PD), where PD is the pupil distance in meters,

[0111] PPC is the convergence point.

[0112] PRC is the point of convergence.

[0113] Typically, Tol_blur = kdof.DoF and Tol_cv = kcv.PaR, where PaR is the Pan radius. Maximum effort is not reached at DoF, so for blur, kdof = kmax>1, while conversely, once the disparity exceeds the Pan radius at the fusion limit, convergence ceases and diplopia occurs, which means kcv = 1.

[0114] For the monocular model, Tol_blur can be chosen to give a maximum effort of about 1 when the maximum tolerable blur kmax.DoF is reached or diplopia occurs:

[0115] When diplopia occurs, accommodation should also cease, which means that at the limit of the fusion reserve or when AS = VS = PPC, the accommodation effort and convergence effort should be the same, which implies kmax = f(DoF, PaR, PPC) and gives the maximum blur in diplopia:

[0116] Cmax=PPC-PRC+PaR=PPA-PRA+kmax.DoF

[0117] Tol_blur = kmax.DoF.Cmax

[0118] Tol_cv=PaR.Cmax

[0119] The maximum effort is obtained at the maximum regulation error kmax.DoF, kmax>1.

[0120] The relationship with kmax and Cmax can also be derived from the following equation, which is obtained by Effort(AS=VS=PPC)=1:

[0121] (1-ACA.CAC) =[PPC-dkF+CAC(PPC-dkV)] 2 (1-AG) / kmax.DoF.Cmax +[PPC-dkV+ACA(PPC-dkF)] 2 (1-VG) / PaR.Cmax

[0122] kmax=[PPC-dkF+CAC(PPC-dkV)] 2 (1-AG) / DoF / {(1-ACA.CAC).Cmax-[PPC-dkV+ACA(PPC-dkF)] 2 (1-VG) / PaR}

[0123] When the effort is below 1 / 3 of kmax, it is considered comfortable, and when the effort is above 2 / 3 of kmax, it is considered uncomfortable.

[0124] kmax can vary depending on refractive error, with myopes typically having a higher kmax than hyperopes because myopes are more efficient at processing blur.

[0125] kmax can also depend on the stimulus, not only on the stimulus conditions (brightness, contrast, spatial frequency, etc.), but also on the motivation.

[0126] Parameters such as dark focus, near point and far point can be derived from specific objective measurements, the individual's prescription and / or age. These parameters can be objectively measured using an autorefractor. Dark focus can first be assessed using the same autorefractor by turning off the stimulus and waiting for a rest period of at least a few seconds (ideally 30 seconds).

[0127] The simplest way to assess dark focus is to measure PPA using standard optometry, which consists in recording the shortest distance at which the stimulus is observed to be blurred, and then deriving dark focus from the model, assuming PR = Rx: dkF = ObjAA / 3 + PR, where PR is the far point. Another simple approach is to use the model to derive ObjAA from age and then derive all other parameters.

[0128] Regulation-convergence model

[0129] Monocular accommodation can be expressed as follows:

[0130] AR=min(max(PRA,AG.(AS-dkF)+dkF,PPA)

[0131] If |AS-AR|>kmax.DoF, then AR=dkF

[0132] Binocular accommodation convergence can be expressed as follows:

[0133] AR=[(AG-CAC.ACA)AS+(1-AG)(dkF+CAC(VS-dkV))] / (1-ACA.CAC)

[0134] VR=[(VG-CAC.ACA)VS+(1-VG)(dkV+ACA(AS-dkF))] / (1-ACA.CAC)

[0135] AR=min(max(PRA,AR),PPA)

[0136] VR=min(max(PRC,VR),PPC)

[0137] If |VS-VR|>PaRHor, then VR=dkV and AR=dkF (or return to the monocular model)

[0138] AS=[(1+d)AS 右眼 +(1-d)AS 左眼 ] / 2, where d=0 if there is no dominant eye, 1>d>0 if the right eye is the dominant eye, and 0>d>-1 if the left eye is the dominant eye.

[0139] AG=ObjAA / (ObjAA+DoF), where ObjAA is the objective adjustment amplitude of the monocular, ObjAA=7.083 / (1+e (0.2031.(年龄-36.2-0.6109) ) and PPA = ObjAA + PRA

[0140] ACA=(VS+dPh AS -dPh Rx ) / AS or ACA = 1-0.005×age, where dPh AS It is dissociative heterophoria, dPh AS +VS=dkV+ACA(AS-dkF),dPh Rx It is a dissociative heterophoria at a long distance, dPh Rx =dkV+ACA.(Rx-dkF)-Rx, where Rx is the spherical equivalent value prescribed for far vision obtained based on subjective optometry.

[0141] CAC=1 / (0.5+ACA)

[0142] VG=Δfr / (Δfr+2PaRHor).(1-ACA.CAC)+ACA.CAC

[0143] dkF=ObjAA / 3+PRA

[0144] dkV=ACA.dkF+dPh PRA , where dPh PRA is a dissociated heterophoria for accommodation of the far point, or assuming dPh PRA = 0, dkV = ACA.dkF

[0145] Δfr is approximately equal to 42.5 diopters.

[0146] Optionally, the personalized near vision index may further include a vertical parallax effort.

[0147] In this case, by way of non-limiting example:

[0148] E p =(vdisp-VR) 2 , where vdisp is the vertical disparity

[0149] E m =(1-VG)VR 2 / VG

[0150] The total effort is [(1-VG)VR 2 / VG+(vdisp-VR) 2 ] / Tol_disp

[0151] For a standard linear response, VR = VG.vdisp, the total effort is:

[0152] [(1-VG).vdisp 2 ] / Tol_disp, where Tol_disp = PaRVer.maxdisparityVer, where PaRVer is the vertical Pan radius and maxdisparityVer is the maximum vertical disparity, which is equal to the vertical fusion reserve (typically 1.5 to 3 diopters)

[0153] VG=(maxdisparityVer-PaRVer) / maxdisparityVer

[0154] 1-VG=PaRVer / maxdisparityVer

[0155] Therefore, the vertical parallax effort can be given by the following formula:

[0156] (vdisp / maxdisparityVer) 2

[0157] In the event that the individual wears ophthalmic corrections or must select new ophthalmic lenses, the method according to the present disclosure may further include using the personalized near vision index obtained in step 14 to assess the visual comfort of the individual while wearing the ophthalmic corrections.

[0158] In any case, methods according to the present disclosure may further include using the personalized near vision index to recommend an ophthalmic correction device that provides optimal visual comfort for the individual.

[0159] The accommodation stimulus AS and the vergence stimulus VS are modified by the lenses. In fact, for a specific stimulus position, each lens in front of each eye has a specific focal error P at the fixation point. 右眼 and P 左眼 , the power error given by the lens power diagram modifies the AS in ASlens as follows:

[0160] ASlens 右眼 =AS+P 右眼

[0161] ASlens 左眼 =AS+P 左眼

[0162] ASlens=[(1+d)ASlens 右眼 +(1-d)ASlens 左眼] / 2, where d=0 if there is no dominant eye, d=1 if the right eye is the dominant eye, and d=-1 if the left eye is the dominant eye

[0163] The focal power error P is S+C / 2, where S is the spherical power and C is the cylindrical power.

[0164] Each lens in front of each eye also has a 右眼 and dp 左眼 Specific prism deviations, which modify VS in VSlens as follows:

[0165] VSlens=VS+dp 右眼 -dp 左眼

[0166] The above formulas are approximations from thin lens theory. To obtain accurate results, ray tracing through the lens should be used to calculate ASlens and VSlens.

[0167] The distribution of lens power and prismatic power deviations depends on the lens design for a given stimulus position. Therefore, the effort level required for different lens designs can be evaluated and designs that reduce effort can be selected. Therefore, the present disclosure makes it possible to predict the comfort level of different lens designs and help consumers choose the most suitable lens design.

[0168] Figure 2 Non-limiting examples of modifications of AS and VS by lenses are shown.

[0169] Consider a given set of physical stimuli i=1,…,n (n=3). Accommodative stimuli ASi for the right eye (referred to as "OD" in the figure) and the left eye (referred to as "OS" in the figure) are shown. The first stimulus corresponds to near vision, the second stimulus corresponds to the glasses cross, and the third stimulus corresponds to a non-specific gaze direction in the right visual field between far vision and intermediate vision.

[0170] The prismatic power deviation dpi for OD and OS is also shown.A set of possible lens designs can then be compared to each other.

[0171] The effort can be calculated for any visual demand. Even though the most relevant effort is for near vision, it may also be related to mixed near, intermediate and distance vision, or even different gaze directions, either in the vertical direction (thus corresponding to the ergma function of the visual index) or in any direction (corresponding to the visual index graph of the lens) .

[0172] Figure 3The estimated visual effort at near for a number of different gaze directions (assuming a relationship between gaze and distance) is shown, based on the required downlight given by the igma function, without the individual wearing any corrective device. The horizontal axis represents the gaze reduction in degrees. As is well known to the skilled person, the igma function gives the relationship between the gaze increase / decrease and the distance of the object being viewed. The lower the gaze, the closer the object.

[0173] It can be seen that for lower addition values ​​above 1.5, the effort required for near vision is unbearable (above 1) without any correction.

[0174] Figure 4 The estimated visual effort at near for a number of different gaze directions (assuming a relationship between gaze and distance) is shown for an individual wearing a corrector, based on the required downlight given by the igma function. The horizontal axis represents the reduction in gaze in degrees.

[0175] It can be seen that for lower additions above 3, the effort becomes greater because the correction for low fixation does not fit the increasingly stringent Egma function requirements.

[0176] According to the present disclosure, an apparatus for determining an individual's personalized near vision index includes a device for measuring at least one of the above-mentioned parameters related to the individual's accommodation, a device for determining a binocular vision model representing the individual's vision as described above, and a device for obtaining the personalized near vision index as described above, wherein the near vision index includes the individual's binocular vision effort when seeing near, and the obtaining device is adapted to evaluate the binocular vision effort based on the measured at least one parameter related to accommodation and the binocular vision model, wherein the measured at least one parameter related to accommodation is provided by the device for measuring the at least one parameter related to accommodation, and the binocular vision model is provided by the device for determining the binocular vision model.

[0177] The means for measuring at least one parameter related to accommodation of the individual may comprise means for assessing the amplitude of accommodation.By way of non-limiting example, such means may comprise an autorefractor.

[0178] In another example, a device for measuring at least one parameter related to accommodation, a device for determining a binocular vision model, and a device for obtaining a personalized near vision index may be combined in a smart phone or a head-mounted virtual reality (HVR) device.

[0179] In a particular embodiment, the method according to the present disclosure is computer-implemented. That is, the computer program product includes one or more instruction sequences that are accessible to a processor and, when executed by the processor, cause the processor to perform the steps of the method for determining a personalized near vision index for an individual. The processor is configured to perform steps 10, 12, and 14 as described above.

[0180] The software may be hosted remotely, for example in the cloud, or locally on the computer.

[0181] The sequence(s) of instructions may be stored in one or more non-transitory computer-readable storage media, including a predetermined location in the cloud.

[0182] While representative methods and apparatus have been described in detail herein, those skilled in the art will recognize that various substitutions and modifications may be made without departing from the scope described and defined by the appended claims.

Claims

1. A method for determining a personalized near vision index of an individual, characterized in that: The method comprises: measuring at least one parameter associated with regulation of the individual; determining a binocular vision model representing the vision of the individual; The personalized near vision index is obtained, wherein the personalized near vision index includes the binocular vision effort of the individual when near vision is evaluated based on the measured at least one parameter related to accommodation and the determined binocular vision model.

2. The method according to claim 1, characterized in that The at least one parameter related to accommodation is taken from the group consisting of accommodation amplitude, full accommodation response from far to near vision, accommodation near point, accommodation far point, dark focus and micro-fluctuation amplitude.

3. The method according to claim 1 or 2, characterized in that: The measurements further include measuring binocular vision of the individual, including measuring at least one parameter among heterophoria, fusional reserve, accommodative convergence / accommodative ratio, convergence accommodation / convergence ratio, other accommodation-convergence linkages, and other convergence abilities.

4. The method according to claim 1, 2 or 3, characterized in that: The binocular vision model includes models of accommodation, convergence, and accommodation-convergence linkage based on blur and parallax.

5. The method according to any one of the preceding claims, characterized in that The binocular vision effort includes motor effort and processing effort, wherein the motor effort is the brain effort made by the individual to adjust and converge, and the processing effort is the brain effort made by the individual to compensate for the blur and the parallax.

6. The method according to claim 5, characterized in that The binocular vision effort is the sum of the motor effort and the processing effort, and the motor effort E is the sum of the motor effort E and the processing effort E for accommodation and convergence, respectively. m and the processing effort E p It is given by the following formula: E m =k m (R-X) 2 E p =k p (S-R) 2 Among them, for regulation and convergence respectively: k m and k p is the predetermined coefficient, S stands for stimulation. R is the total reaction, X is the reflex response to the accommodation and the convergence, respectively.

7. The method according to any one of the preceding claims, characterized in that The individual wears an ophthalmic correction, and the method further includes using the personalized near vision index to assess the individual's visual comfort while wearing the ophthalmic correction.

8. The method according to any one of the preceding claims, characterized in that The method further includes using the personalized near vision index to recommend an ophthalmic correction device that provides optimal visual comfort for the individual.

9. The method according to any one of the preceding claims, characterized in that The personalized near vision index adopts a discrete value.

10. The method according to any one of claims 1 to 8, characterized in that The personalized near vision index is a continuous scale.

11. The method according to any one of the preceding claims, characterized in that The personalized near vision index further includes a vertical parallax effort.

12. The method according to claim 11, characterized in that The vertical parallax effort is given by the following formula: (vdisp / maxdisparityVer) 2 Among them, vdisp is the vertical disparity, maxdisparityVer is the maximum vertical disparity, and the maximum vertical disparity is equal to the vertical fusion reserve.

13. A device for determining a personalized near vision index of an individual, characterized in that The device comprises: means for measuring at least one parameter related to regulation of said individual; means for determining a binocular vision model representing the vision of the individual; A device for obtaining the personalized near vision index, wherein the personalized near vision index includes the binocular visual effort of the individual when seeing near, and the obtaining device is adapted to evaluate the binocular visual effort based on the measured at least one parameter related to accommodation and the binocular vision model, wherein the measured at least one parameter related to accommodation is provided by the device for measuring the at least one parameter related to accommodation, and the binocular vision model is provided by the device for determining the binocular vision model.

14. A computer program product, characterized in that The computer program product comprises one or more sequences of instructions which are accessible to a processor and which, when executed by the processor, cause the processor to implement a method for determining a personalized near vision index for an individual, the processor being configured to: obtaining at least one measured parameter related to regulation of the individual; determining a binocular vision model representing the vision of the individual; The personalized near vision index is obtained, wherein the personalized near vision index includes the binocular vision effort of the individual when near vision is evaluated based on the measured at least one parameter related to accommodation and the determined binocular vision model.

15. A non-transitory information storage medium, characterized in that: The non-transitory information storage medium stores one or more instruction sequences that can be accessed by a processor and, when executed by the processor, cause the processor to implement a method for determining a personalized near vision index for an individual, the processor being configured to: obtaining at least one measured parameter related to regulation of the individual; determining a binocular vision model representing the vision of the individual; The personalized near vision index is obtained, wherein the personalized near vision index includes the binocular vision effort of the individual when near vision is evaluated based on the measured at least one parameter related to accommodation and the determined binocular vision model.

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