Method, device and computer program product for determining the sensitivity of at least one eye of a test subject

Abstract

The invention relates to a method for determining the sensitivity of at least one eye of a test subject based on at least two pairs of visual acuity and refraction values provided, wherein at least one of the pairs of visual acuity and refraction values is provided by the following steps: - projecting a target with an adjustable target refraction into at least one eye of the test subject, wherein the target is configured to verify a predetermined visual acuity; and - determining a visual acuity limit refraction of the at least one eye of the test subject associated with the predetermined visual acuity by changing the target refraction of the target projected into the at least one eye of the test subject and detecting a test subject action that causes a determinable identifiability of the target of the test subject to have changed at the time of the test subject action.

Description

[0001] The present invention relates to a method, a device and a corresponding computer program product for determining the sensitivity of at least one eye of a test subject or of a spectacle wearer. Furthermore, the present invention relates to a method and a device for calculating, optimizing or evaluating a spectacle lens for at least one eye of a test subject taking into account the sensitivity of at least one eye of the test subject determined according to the present invention. Furthermore, the present invention relates to a method and a device for manufacturing a spectacle lens and to a spectacle lens manufactured using such a method or device.

[0002] The published patent application WO 2013 / 104548 A1 describes an optimization of a spectacle lens based on a wavefront determined in a direct calculation of light through the eye. The wavefront is evaluated on one plane of the eye and not, as standard, on the vertex sphere (VS) and thus depends on the properties of the eye. Using this method, the influence of the cornea and all other individual properties of the eye, such as deviations of the anterior chamber depth or other geometric parameters of the average population, can be directly included in the optimization of the spectacle lens by the wavefront. The basis of this optimization method is an objective function which, in addition to the properties of the calculated wavefront, including their higher-order aberrations (HOA), depends on target specifications and weights which are required for certain properties of the wavefront in the eye.

[0003] In a method for optimizing a spectacle lens according to the prior art, the spectacle lens is optimized by minimizing or maximizing an objective function which includes the actual value and a corresponding target value of at least one imaging property or aberration of the spectacle lens. The at least one imaging property or aberration can constitute a direct quantification of the deviation of the wavefront from a reference wavefront. An exemplary objective function is, for example, the following function:

[0004]

[0005] wherein:

[0006] i (i = 1 to N) denotes an evaluation point on the spectacle lens;

[0007] R act (i) denotes the actual spherical effect or the refraction error of the i-th evaluation point;

[0008] R targ (i) denotes the target spherical effect or the target refraction error at the i-th evaluation point;

[0009] Ast act (i) denotes the astigmatism or the astigmatism error at the i-th evaluation point;

[0010] Ast targ (i) denotes the target astigmatism or the target astigmatism error at the i-th evaluation point.

[0011] Variable G R,i A,i ... is a weight of a relevant imaging property or aberration used in the optimization.

[0012] As described in WO 2015 / 104548 A1, the imaging properties or aberrations of an eyeglass lens can be evaluated at a vertex sphere or an evaluation plane or an evaluation surface in the eye.

[0013] It was later found that quantifying the wavefront deviation directly in diopters without taking into account the effective pupil size (as the effective pupil size depends on the depth of focus) is not the best criterion to describe and evaluate the perception of an eyeglass wearer through an eyeglass lens. Based on this insight, it was proposed in DE 10 2017 007 663 A1 to directly consider the visual acuity (visual sharpness) in the objective function or power function. The visual acuity included in the objective function or power function depends by way of assignment on at least one imaging property or aberration of an eyeglass lens system, which can be evaluated at a suitable evaluation surface (for example at a vertex sphere or in the eye). The eyeglass lens system can consist of at least one eyeglass lens (for example of an eyeglass lens of an ophthalmic eyeglass). However, the eyeglass lens system preferably includes further components, such as a model eye or an eye model, which can be based on at least one individual parameter of the average of eyeglass wearers or of the eyeglass wearer's eye. In other words, the eyeglass lens system based on the assignment of at least one imaging property or aberration to the visual acuity of the eyeglass wearer can be an eyeglass lens / eye system.

[0014] As described in DE 10 2017 007 663 A1, the exemplary objective or power function depending on the visual acuity V by assigning at least one imaging property or aberration ΔU s,j to the visual acuity of the eyeglass wearer or of the average eyeglass wearer can for example have the following structure:

[0015]

[0016] In the above equation, V(ΔU s,j (i)) denotes a function describing the dependence of the visual acuity on at least one imaging property or aberration of the eyeglass lens system at the i-th evaluation point (i = 1, 2, 3,..., N) on the evaluation surface. In other words, V(ΔU s,j (i)) describes an exemplary assignment of at least one imaging property or aberration of the eyeglass lens system to the visual acuity of the test subject or of the eyeglass wearer or of the average eyeglass wearer when observing an object through the eyeglass lens system. This argument ΔU s,j ​is generic and can represent any imaging property or aberration of the spectacle lens system, which describes the influence of the spectacle lens system on a light beam emerging from an object or the difference of the influence of the spectacle lens system on a light beam emerging from an object and a reference light beam converging on the retina of the eye. In this case, one or more imaging properties or aberrations can be included in the objective function or power function and can be evaluated, the index j, j > 1, denoting the j-th imaging property or aberration.

[0017] V act (ΔU s，j (i)) represents the visual acuity, which is determined on the basis of the assigned and actual values of the at least one imaging property of the spectacle lens to be calculated (e.g. to be optimized) or evaluated at the i-th evaluation point, and V targ (ΔU s，j (i)) represents the corresponding target value of the visual acuity.

[0018] The at least one imaging property or aberration can be calculated or evaluated on a suitable evaluation surface. The index "s" thus stands for any evaluation surface of the at least one imaging property or aberration ΔU s,j . The evaluation surface may, for example, be a planar (evaluation plane) or curved (e.g. spherical) surface. The evaluation surface may, for example, be a vertex sphere or a surface in the eye, for example one of the following planes or surfaces:

[0019] a plane or (e.g. spherical) surface behind the cornea,

[0020] a front surface of the lens of the eye or a plane tangential to the front surface of the lens of the eye,

[0021] a back surface of the lens of the eye or a plane tangential to the back surface of the lens of the eye,

[0022] an exit pupil plane (EP), or

[0023] a plane of the back lens surface (L2).

[0024] The variable represents a weight of the visual acuity predetermined by the assignment of the imaging property ΔU s,j at the i-th evaluation point.

[0025] In this case, one of the visual acuity models described, for example, in DE 10 2017 007 663 A1 or any other suitable visual acuity model, which inter alia describes the visual acuity as a function of diopters or pseudo-diopters, can be used, and in particular can preferably be incorporated into the optimized objective function in conjunction with the specification, such as the transformed visual acuity model in conjunction with the target specification and the weights. It should be noted at this point that, as part of the present specification, a sensitivity measure (as described below) can preferably be used on the basis of such a visual acuity model as a functional dependency of the visual acuity values on the diopters / pseudo-diopters. In particular, the preferred sensitivity measure can be used as a derivation of the visual acuity model from the diopters / pseudo-diopters, i.e. as a function of the visual acuity values of the diopters / pseudo-diopters.

[0026] By means of the objective function, the spectacle lens can likewise be evaluated, wherein an actual value of at least one imaging property of the spectacle lens to be evaluated is calculated at at least one evaluation point of the spectacle lens to be evaluated and compared to a corresponding target value.

[0027] It is likewise clear from DE 10 2017 007 663 A1 that, first and foremost, for the calculation, optimization and / or manufacture of highly customized high-quality spectacle lenses, the so-called sensitivity, i.e. the change in visual acuity with pseudo-diopters, is useful. For example, the assignment of at least one imaging property or aberration of the spectacle lens system to the visual acuity or function V(ΔU s,j (i)) of the spectacle wearer can depend parametrically on the measured output visual acuity and / or the determined sensitivity of the spectacle wearer.

[0028] In the context of the present application, the sensitivity is a variable, in particular a phenomenological variable, used in spectacle optics and ophthalmology, or is a parameter by means of which a dependency of the visual acuity on the pseudo-diopters can be described or stated. The sensitivity of the eye is understood to mean, in particular, the change in the visual acuity of the eye in the event of a change in the pseudo-diopters. In particular, the sensitivity can be defined as a derivation of the visual acuity from the pseudo-diopters or as a local derivation of the visual acuity from the pseudo-diopters at a certain pseudo-diopter. In this case, the pseudo-diopter is the deviation of the effect or diopter applied to the at least one eye of the test subject during the visual acuity determination from the ideal diopter determined or known for the at least one eye. The ideal diopter (hereinafter also referred to as the best diopter or target diopter) can be determined, for example, from conventional objective and / or subjective diopter measurements. In particular, the sensitivity describes how much the visual acuity changes when the optical effect or correction in front of the eye changes. The sensitivity can be quantitatively described, in particular, by means of a sensitivity measure and / or by means of a visual acuity model.

[0029] Therefore, the sensitivity of at least one eye of a test subject can be taken into account when calculating and / or manufacturing individual spectacle lenses, in particular when manufacturing multifocal spectacle lenses like ophthalmic spectacle lenses. The spectacle lenses can have transitions between regions with different optical correction, i.e. for example, between a viewing point for distance vision and a viewing point for near vision. These transitions between regions of the spectacle lenses with different optical correction can be configured differently. In this case, for example, reference is made to hard transitions or soft transitions depending on the steepness or flatness of the refractive change along the transition. In highly customized, high-quality spectacle lenses, this transition (and other regions of the spectacle lenses) can in particular be adapted to the sensitivity of at least one eye of the test subject or spectacle wearer.

[0030] In order to determine the sensitivity of at least one eye of a test subject to a focus loss, the presence of at least two applied effects and the resulting visual acuity in each case is required. The relevant model for calculating the sensitivity and the corresponding formula are described below. According to the prior art, the effects are applied to the test subject or at least one eye of the test subject in order to determine the sensitivity (for example, using a conventional trial lens set in increments of 0.25 dpt). Based on the visual acuity chart with the quantized size and / or the quantized visual acuity level of the optotypes, the corresponding visual acuity is determined for the applied effect. Furthermore, it is necessary to determine the best correction (or best refraction or target refraction) for the test subject in order to possibly convert the applied effect into a pseudo-refraction.

[0031] In the context of the present application, it has been found that the double quantification associated with the conventional method leads to a high level of measurement uncertainty. Furthermore, it has been found that the conventional method is not only complex, but also has a negative psychological impact, since after the determination of the best refraction, at least one eye of the test subject has a poorer correction, which the test subject then has to use to complete the visual tasks in order to determine the sensitivity. This sequence is necessary in the conventional method, because only with the best refraction known, a defined blur can be set for the visual acuity measurement.

[0032] Therefore, one problem solved by the present application is to determine the sensitivity of at least one eye of a test subject in an improved manner, in particular in a simple and fast manner, which is particularly required for calculating, optimizing, evaluating and / or manufacturing highly customized, high-quality spectacle lenses. Furthermore, one problem solved by the present application is to provide a method and a device for calculating, optimizing, evaluating and manufacturing spectacle lenses, which are highly customized and high-quality due to the consideration of the sensitivity of at least one eye of a test subject. It is also one problem solved by the present application to provide such improved spectacle lenses. The subject matter of the independent claims solves these problems. Advantageous embodiments are contained in the dependent claims.

[0033] A first independent aspect for solving this problem relates to a method for determining the sensitivity of at least one eye of a test subject based on at least two pairs of provided visual acuity and diopter values. In this case, at least one of the pairs of visual acuity and diopter values is provided by the following steps:

[0034] - projecting a target having an adjustable target diopter into at least one eye of the test subject, wherein the target is configured to verify a predetermined visual acuity; and

[0035] - determining a visual acuity limit diopter of at least one eye of the test subject associated with the predetermined visual acuity by changing the target diopter of the target projected into at least one eye of the test subject and detecting a test subject action that causes a determinable identifiability of the target of the test subject to have changed at the time of the test subject action.

[0036] As already explained at the outset, the "sensitivity" (to a lack of focus) of at least one eye of the test subject is understood to mean the dependency of the visual acuity of at least one eye of the test subject on the pseudo diopter, wherein the "pseudo diopter" is the deviation of the effect or diopter applied to at least one eye of the test subject during the determination of the visual acuity from the ideal or best diopter (target diopter) determined or known for at least one eye.

[0037] “Visual acuity” is a measure of the visual (central) acuity of at least one eye of a test subject. Usually, the visual acuity is determined under strong light conditions. In particular, the visual acuity can be defined as the reciprocal value of the smallest perceptible gap in a standard test character, namely the Landolt ring. In humans, the visual acuity can be determined by an eye test. To do this, optotypes are presented to the test subject and it can be clearly seen from the answers of the test subject whether the test subject has correctly identified them or not. The visual acuity depends on the optotypes that the test subject can identify in the set or applied diopter state. The optotypes generally have a defined size, brightness, shape and contrast. These optotypes can be displayed or projected onto a chart. The advantage of using a projector instead of a chart is that it is not affected by the test distance. There are DIN standards for reproducible visual acuity tests. According to these standards, the standard optotypes are so-called Landolt rings, a ring of defined width with a gap of the same width, which can be arranged in eight different directions. By identifying the direction of the gap, the test subject demonstrates their resolution ability to correspond at least to the width of the gap. In practice, however, because it is easier to understand, standardized digital images are used as optotypes. There are other standardized optotypes, such as the “Snellen E”, the “Pflüger trident E” with a shorter middle stroke, and others suitable for testing visual acuity in illiterates and preschool children as well as for non-verbal communication.

[0038] In determining the visual acuity, a distinction is made between the visual acuity with a correction, such as glasses or contact lenses, and the visual acuity without a correction. Here, the visual acuity without a correction is referred to as the natural visual acuity. The abbreviations “s.c.” (“sine correctione”, Latin for “without correction”) and “c.c.” (“cum correctione”, Latin for “with correction”) are also often used.

[0039] In particular, the sensitivity of at least one eye can be determined on the basis of a sensitivity measure. By using a sensitivity measure, the sensitivity can be assessed even when the applied diopter values do not have a predetermined distance from one another.

[0040] The sensitivity measure represents the dependency of the visual acuity on the (pseudo) refraction. In this case, the distance between two refraction values can be a component of the sensitivity measure. The sensitivity measure can be defined in a metric space of refraction values. A visual acuity value can be assigned to each refraction value of the sensitivity measure and vice versa. The refraction can be defined in a space of at least three dimensions, for example. The refraction values can be described by the coordinates s, c and a, for example. Here, s can depend on the strength of the spherical optical correction, c on the strength of the cylindrical optical correction and a on the axis position of the cylindrical correction. In this metric space of refraction values, at least the refraction values of the predetermined first visual acuity and the predetermined second visual acuity can be determined and thus known in the calculation of the sensitivity. The sensitivity measure can be used to determine the sensitivity on the basis of two different refraction values, which are in principle arbitrary. By using this type of sensitivity measure, the determination of the sensitivity is independent of the visual acuity measurement with the predetermined refraction values, which is standard in conventional methods. In this case, the determination of the sensitivity can be independent of the visual acuity measurement with at least one predefined and / or fixed refraction distance from the refraction result (or from the best refraction or target refraction) and also independent of the visual acuity measurement with at least one predetermined and / or fixed relative refraction distance between two applied refractions. Thus, the measurement data required for determining the sensitivity determination can be easier for the optometrist and the test person.

[0041] Embodiment of the sensitivity measure

[0042] The sensitivity can be calculated by means of a metric space in which different refraction values represent individual points. The refraction values can be represented three-dimensionally, for example, such as by the coordinates s, c and a. Here, s can depend on the strength of the spherical correction and be represented in diopters, for example (also abbreviated as dpt). c can depend on the strength of the cylindrical correction and can be represented in diopters, for example. a can depend on the axis position of the cylindrical correction and can be represented in degrees, for example, from 0 to 180 degrees. Alternatively, other coordinates can also be used for this purpose.

[0043] In the following, by way of example, a best refraction (also referred to as best or ideal refraction in the context of the present specification), i.e. in particular a specific objective and / or subjective refraction result, is assumed in the sensitivity measure, which is represented by s0, c0 and a0, the associated visual acuity by v0. When the method is carried out, at least two pairs of visual acuity and refraction values are provided. In general, n refractions sn, cn, an and associated visual acuities vn are provided, n being an integer greater than or equal to 2. i , c i , a i The associated visual acuity vn can be provided. iwhere i e [1,..., n] and n > 2. In this case, at least one value pair of visual acuity and refraction of at least one eye of the test subject can be known and provided as a known value pair. The provision is in particular comprised in determining and / or measuring.

[0044] In a possible sensitivity measure, the distance of the best refraction i with the central sphere d i and the cylinder a i in the refraction of the test subject is calculated using equation (1):

[0045]

[0046] Simple bilinear model of the sensitivity measure with knowledge of the target refraction

[0047] In one embodiment of the bilinear model of the sensitivity measure, for the dependency of the visual acuity, the following relationship listed in equation (2) applies to each individual measurement of the refraction i. In this case, in a simplification, it can be assumed that the test subject cannot compensate for the blur by adaptation.

[0048] lg v i = m d · |d i | + m a · a i + lg v0 (2)

[0049] Here, m d represents the sensitivity with the spherical distance and m a represents the sensitivity with the cylinder distance. This division between the spherical pseudophakia and the cylinder pseudophakia can be used to take into account that the reaction of the test subject to these two components of the pseudophakia can be very different. For example, it can be determined from the data of D. Methling: Bestimmung von Sehhilfen [Determination of visual aids], 2nd edition, Ferdinand Enke Verlag, Stuttgart 1996 that, for example, equation (3) applies to the empirically determined average population:

[0050]

[0051] In general, the above equation (2) has the independent parameters m a , m d , v0. Therefore, the equation system (2) can be clearly solved by three measurements i = 1, 2, 3 of the refraction (s1, c1, a1, s2, c2, a2; s3, c3, a3) at three (in particular predetermined) different visual acuity values to give the equation group (2a):

[0052]

[0053] where denominator = (a2-a3)|d1| + (a3-a1)|d2| + (a1-a2)|d3| (2a)

[0054] Here, the visual acuity measurement can be performed under optimal correction conditions, e.g. at the target refraction, in particular determined from objective and / or subjective refraction measurements. When i = 3, the following equation applies: (s3, c3, a3) = (s0, c0, a0). Then, under these optimal correction conditions, a3= a0= 0 and d3= d0= 0. Thus, the third of equation (2a) is automatically satisfied. Then, the other equations take the following form of equation system (4):

[0055]

[0056] where denominator = a2|d1| - a1|d2| (4)

[0057] Thus, equation system (4) provides an exemplary embodiment of a simplified bilinear model of the sensitivity measure. Equation system (4) can be solved with the knowledge of the target refraction and the knowledge of two additional refraction values for two additional visual acuity values (for i = 1, 2). Thus, the sensitivity can be determined from equation system (4). The sensitivity describes the dependency of the visual acuity on the (pseudo) refraction. This can be described, for example, by the values m a and m d .

[0058] If more than two additional refraction states are measured at predetermined visual acuity values in addition to the visual acuity v0 at the target refraction state, m d and m a can be determined from all data by means of a compensation method, e.g. a least squares method, to determine the sensitivity more precisely. Furthermore, outliers can be excluded from the measurement data to improve the quality of the sensitivity determination.

[0059] Simplified linear model of the sensitivity measure with knowledge of the target refraction

[0060] In a more simplified, less customized model of the sensitivity measure, e.g. when only one measurement is available for the pseudo refraction i = 1, the relationship between the spherical and the cylindrical refraction distance can be assumed according to equation (5):

[0061]

[0062] Here, the parameter f can be derived from empirical values and can for example be a scalar. With the assumption according to equation (5), the equation system (2) simplifies to give the following equation (6):

[0063] lg v i = m · (d i + f · a i ) + lg v0lg v i = m · (a i + f · d i ) + lg v0 (6)

[0064] Thus, the sensitivity m can be determined from the measurement of the pseudo refraction i in equation (7):

[0065]

[0066] The value of f can be derived from the relevant technical literature, for example f = 1 / 2 can be applied, which is derived from Applegate, R. A, Sarver, E. J, Khemsara: “Are all aberrations equal?” Refract Surg. 2002, 18, pp. 556-562. Alternatively, f = 1 can be applied, which value is from Atchison et al.: “Blur limits for defocus, astigmatism and trefoil”, Vision Research, 2009.

[0067] In this case, no assumption of a linear relationship is required for equation (5). Alternatively, more complex relationships can be formed and, for example, based on a plurality of independent parameters and / or refraction measurements, the sensitivity can be derived therefrom by introducing a corresponding analytical relationship; see equation (4) and equation (7). The sensitivity can also be derived from compensation methods, for example the least squares method.

[0068] Further model of sensitivity measure with knowledge of subjective refraction

[0069] The sensitivity can also be calculated on the basis of another model. For example, from the known model in R. Blendowske: “Unaided visual acuity and blur: “Simple model””, Optometry and Vision Science, Vol. 92, No. 6, 2015, these models are characterized by their particularly simple nature and are based on only a few parameters. This simple model is particularly suitable for calculating the sensitivity and the adjustment in the case of low data, for example because it effectively avoids overfitting.

[0070] If a large number of parameters are individually available, a model with many different parameters is more suitable, for example as described in DE 10 2017 007 663 A1.

[0071] In principle, a number of different models can be used. The model used in a given case can depend on the number of pairs of visual acuity and refraction values provided or determined. When the number of pairs of visual acuity and refraction values is large enough, a relatively complex, not necessarily linear model can be formed, the parameters of which can be adjusted according to the measurements.

[0072] The models listed above as examples can be generalized, such as by describing a function of visual acuity that comprises a contour of constant visual acuity in the power vector space, which corresponds to an ellipsoid or ovoid containing the point of maximum visual acuity. This can be done similarly to the method presented in A. Rubin and W. F. Harris: "Closed surface of constant visual acuity in symmetric refractive space", Optometry and Vision Science, Vol. 78, No. 10, 2001. In this case, the axis ratios can vary in the range of 0.25 to 4, respectively. Instead of individually measured values, the average, median or other estimate of the corresponding model parameters of a population can be used to calculate the visual acuity.

[0073] In one exemplary embodiment, the generalization of the above equation (6) results in a different factor f, such as equation (8):

[0074]

[0075] Here, a i ort and a i ort denote the astigmatism of the pseudophakia with the orthogonal (J0) and the tilted (J45) axis positions, respectively, and are defined as:

[0076] and

[0077]

[0078] Here, R denotes a rotation matrix, which determines the orientation of the ellipsoid of constant acuity of vision in the power vector space of the vector The eigenvalues m1, m2, m3 denote the sensitivity to blur in the direction of the first, second and third column vectors of the rotation matrix R in the power vector space.

[0079] Embodiment of a model of sensitivity measure without knowledge of target refraction

[0080] In some embodiments, the sensitivity can be determined without knowing or being certain about the target refraction. This can occur when the associated refraction or the visual acuity limit refraction is determined for a plurality of predetermined different values of visual acuity. In this case, the optimal refraction or the target refraction can be determined from the measurement data collected in the process. Furthermore, the actually determined optimal refraction can be checked by means of a model of the sensitivity measure from the measurement data.

[0081] In this case, it can be assumed that the test subject is able to compensate for the blur towards the negative direction, i.e. the intentional false refraction, by adapting at least one eye. In this case, the point of the visual acuity curve bending can be chosen in a linear model according to the above equations (2) and (6). In a nonlinear model in which saturation is present, the optimal refraction can be directly calculated as a parameter of the equation system. For this purpose, the false refraction, i.e. the distance d i and a i , needs to be replaced by the difference between the optimal refraction and the correction degree set or applied in the corresponding formula, i.e. in particular in equation (1).

[0082] The above embodiments of the model of the sensitivity measure are examples of how the sensitivity can be determined in the context of the present application.

[0083] The target can be, in particular, an actual target (or real object) or a virtual target (or virtual object). In particular, the target can be an actual object or a virtual projected object (or projected virtual object). The target can be realized, for example, by a display (e.g. with one or more lenses and / or with one or more mirrors), by a light field display and / or by a Badal optometer (which allows a constant magnification, although the effect changes), and can be projected into at least one eye of the test subject.

[0084] A “virtual object” or “virtual target” is understood, in particular, as an optical imaging system which generates wavefronts emitted from a virtual object point such that they impinge on at least one eye of the test subject. In this case, the wavefronts generated by the virtual target (and each corresponding to a virtual object point) and impinging on at least one eye of the test subject have an adjustable spherical curvature and / or an adjustable cylindrical curvature component, the cylindrical curvature component preferably being adjustable both with respect to the curvature value and with respect to the axis position.

[0085] The virtual position of the virtual object (target) can preferably be changed, so that in this way a different accommodation state of the at least one eye can be stimulated. In particular, the position of the virtual object can preferably be changed between a position for stimulating hypermetropic accommodation and a position for stimulating myopic accommodation. Furthermore, the position of the virtual object can preferably be adjusted so that the at least one eye of the test subject can no longer accommodate the virtual object. In this case, the virtual object (target) can only be perceived by the test subject out of focus in all directions. This means that the ciliary muscles relax. This state is referred to as "blurred" state.

[0086] The target is projected into the at least one eye of the test subject with an adjustable or variable target refraction (or target effect). This projection can be achieved by means of an optical system with which the effect or the refraction of the target, i.e. the target refraction, can also be adjusted and / or changed. In the context of the present application, the "target refraction" is therefore understood to be the refraction (applied or caused by the optical system) with which the target is projected into the at least one eye of the test subject or with which the target is provided to the at least one eye of the test subject (in particular the spherical and / or astigmatic refraction).

[0087] The optical projection into or onto the eye of the test subject is in particular considered to be the target, so that this projection generates an image on the retina of the eye which corresponds to the image of an actual object at a certain distance from the eye. This particular distance is also referred to here as the virtual position of the virtual target. In other words, in the meaning of the present specification, the target is in particular the imaging of the object in the at least one eye of the test subject. For example, a backlit transparency can be used as the object. Since in the case of a virtual target the target is not an actual object in the (direct) virtual position, the virtual position can also be simulated infinitely by appropriately configuring the optical system for the projection. This corresponds to a wavefront converging towards the eye (i.e. in the direction of propagation).

[0088] The projection of a target (in particular a virtual target) into the at least one eye of the test subject by means of an optical system is in principle known and will therefore not be discussed in more detail in the context of the present application. For example, the projection of a target into the at least one eye of the test subject is described in K. Nicke and S. Trumm: "Augenoptik der Zukunft - Schritt 3 Der DNEye Scanner" [Optics of the future - Step 3 The DNEye Scanner], Der Augenoptiker [Optician], June 2012, or also in DE 10 2013 000 295 A1.

[0089] ​The target projected into the at least one eye of the test subject is configured to verify a predetermined, in particular predefined and / or known visual acuity (or a predefined visual acuity level). Herein, "verifying a predetermined visual acuity" can in particular be understood to mean that, by means of the target, it can be determined or established (in particular based on the actions of the test subject) whether the at least one eye of the test subject reaches the predetermined visual acuity or the predetermined visual acuity level. In other words, the target specifies a certain visual acuity or a certain visual acuity level, and it can be determined whether the at least one eye of the test subject reaches it (in particular based on the actions of the test subject). In particular, the target (in particular the determined size) is provided such that the predetermined visual acuity or the predetermined visual acuity level is assigned or can be assigned to the virtual target. In other words, the target is a target with the predetermined visual acuity or the predetermined visual acuity level. This means that as long as the at least one eye of the test subject reaches at least or has the visual acuity or the visual acuity level predetermined by the target, the test subject, in particular with the ideal refraction or with the correction of the possible refractive error of the at least one eye of the test subject, recognizes or is able to identify the target.

[0090] In particular, the target can comprise or be an optotype suitable for determining the visual acuity. In this case, the size or the size of the optotype depends on the predetermined visual acuity or the predetermined visual acuity level. In particular, the size or the size of the optotype is chosen such that only a test subject with a visual acuity that at least corresponds to the predetermined visual acuity or the predetermined visual acuity level can recognize and / or identify the optotype.

[0091] The target can also be an image or a photograph containing two or more details, the recognition of each detail can be assigned a predetermined visual acuity or a predetermined visual acuity level. The image can in particular show an object such as a road extending into the distance, the sky, a distant hot air balloon, etc., which can give the observer a sense of openness or distance. The above-mentioned details contained in the image, for example, a symbol or a panel on a hot air balloon or a hot air balloon basket, a cloud or a symbol in a cloud, a line on a road, a symbol on a roadside sign, etc., are expressly included in the context of the present specification by the term "optotype". A particularly suitable symbol as an optotype is, for example, one or more concentric rings, which merge together to form a circle at a given focus deficiency.

[0092] The visual acuity or the visual acuity level of a target, of a plurality of targets or of optotypes can be determined, for example, in a known manner by calculating the angle of view of the details or by identifying test subjects with known visual acuity properties.

[0093] After projecting the target into the at least one eye of the test subject, the visual acuity limit diopter of the at least one eye of the test subject associated with the predetermined visual acuity or the predetermined visual acuity level is determined.

[0094] In the context of the present invention, the "visual acuity limit diopter" or "visual acuity level limit diopter" is understood to mean that the identifiability of the target of the test subject changes at this diopter or limit diopter. In particular, the "visual acuity limit diopter" or "visual acuity level limit diopter" is understood to mean the diopter or limit diopter at which the test subject

[0095] a) can first identify and / or recognize the virtual target applied to them or projected into their at least one eye by changing the target diopter (imposed or caused by the optical system) and is characterized by a predetermined visual acuity or a predetermined visual acuity level starting from a blurred state, or

[0096] b) can no longer identify and / or recognize the target or the virtual target starting from a state of unblurred images by changing the target diopter (imposed or caused by the optical system).

[0097] The visual acuity limit diopter is determined by changing the target diopter of the target projected into the at least one eye of the test subject and by detecting an action of the test subject (for example, a message or an input from the test subject, in particular the actuation of a button or a joystick). The target diopter can be changed incrementally or, preferably, continuously. The target diopter is preferably changed monotonously and / or constantly. The test subject action signals or determines that the identifiability of the target of the test subject has changed at the time of the test subject action. In other words, with the aid of the test subject action, the test subject signals that they can identify or recognize the target for the first time at the target diopter provided or applied at the time of the test subject action or can no longer be able to identify or recognize the target for the first time. In particular, the visual acuity limit diopter corresponds to the target diopter or the target effect provided at the time of the test subject action or applied by the optical system.

[0098] The sensitivity of the at least one eye of the test subject is determined taking into account the predetermined visual acuity or the predetermined visual acuity level and the determined associated visual acuity limit diopter.

[0099] The method according to the invention can in particular be carried out as a component of an automated refraction or an aberrometry measurement. To this end, at least one pair of visual acuity levels and associated application effects is detected. This is achieved with the aid of a signal from the test subject during a change in the effect applied at a target having a defined visual acuity level, i.e. a defined target size.

[0100] As already mentioned, the determination of the acuity requires at least two levels of visual acuity and the associated application effect. In the conventional approach, with the defined application effect, it is determined which level of visual acuity the test subject reaches with each of these effects (i.e. with which size the test subject can still recognize the optotypes). However, in the method according to the application, for at least one of these pairs, the size of the optotypes (and thus the level of visual acuity) remains unchanged and the applied effect is varied. The test subject signals when they can still recognize or no longer recognize the optotypes with the defined size.

[0101] In contrast to the prior art, in the present application, for the determination of the acuity, the level of visual acuity for a specific application effect (with a known or a priori unknown pseudophakia) is not required, but the application effect necessary to reach a predetermined level of visual acuity.

[0102] The method according to the application allows the determination of the acuity in a simple and fast manner. In particular, the method according to the application allows the determination of the acuity (as a subjective measurement variable) in a simple manner during a normal objective refraction measurement without great additional complexity. In particular, complex measurements can be avoided during the subjective refraction and, after the determination of the best refraction, the step of providing the test subject with a poorer correction and which should be used to complete the visual task can be omitted, which has a negative psychological impact. Furthermore, the method according to the application can advantageously be very well associated with further measurements for determining individual parameters of a high-quality spectacle lens (e.g. myopia measurement, pupil measurement, corneal pigmentation) and measurements for optometric or ophthalmological screening or measurements for establishing findings (e.g. corneal pigmentation, opacity, thickness measurement, tomography, intraocular pressure measurement or retinal imaging).

[0103] In a preferred embodiment, prior to the step of projecting the target configured to verify (or determine) the predetermined level of visual acuity into at least one eye of the test subject, an objective and / or subjective refraction result of the at least one eye of the test subject is also determined (in particular a combined refraction result based on objective and subjective measurements, wherein further data such as low and / or high order aberrations from an aberrometer or other biometric data such as corneal shape, lens to retina distance, anterior chamber depth etc.). In the context of the present application, the "refraction result" is in particular understood to be a determined refraction value. In this way, the determination of the acuity can be associated with one or more aberration measurements or automatic refraction measurements compared to the previous method. In particular, the determination of the visual acuity can be associated with the measurement of the automatic refraction or the aberration data in the non-adapted state and in the adapted state.

[0104] The objective refraction value or objective refraction result is preferably determined in a blurred state. To this end, a target (e.g. an image or a picture) can be presented to the test subject or a corresponding virtual target can be projected into at least one eye of the test subject (by means of an optical system), which has the effect that the test subject can only identify the target in a misaligned (or not completely aligned) focus, which means that the ciliary muscles of at least one eye of the test subject are relaxed. This blurring can be performed with an additional effect of e.g. about 1.25 dpt to 1.5 dpt compared to the best refraction of at least one eye of the test subject.

[0105] In a specific embodiment, the accommodation state of the eye can also be tracked in order to thus obtain more reliable sensitivity values.

[0106] Preferably, prior to the step of changing the target refraction state, a target is projected into at least one eye of the test subject, the starting target refraction state of which is such that the test subject can only identify the target in a misaligned (or not completely aligned) focus and / or cannot identify it. In other words, the starting target refraction is preferably chosen such that the test subject cannot focus the target or the optotype by accommodation. This is achieved in particular in that the starting target refraction is shifted in the positive direction compared to the best refraction of at least one eye of the test subject. Only by changing the target refraction in the negative direction can a state be reached in which the test subject can identify and / or recognize the target or the optotype. This has the additional advantage that the test subject initially does not know the target or the optotype and thus with a higher probability performs the test subject action at the correct time, i.e. only when they can actually recognize the target or the optotype. However, if the test subject knows the target or the optotype in advance or at the beginning of the measurement (due to a corresponding starting target refraction at which they can see the target or the optotype in focus), it has been found in the context of the present application that, although this method is possible as an alternative, it is not as good as the above-mentioned preferred embodiment in terms of accuracy and reliability of the method. This is because the test subject who knows the target or the optotype in advance tends to be inclined to signal the time at which they can no longer identify and / or recognize the target or the optotype after the target refraction has been changed slightly too late in the positive direction.

[0107] In another preferred embodiment, prior to or after the step of projecting a target configured to verify a predetermined visual acuity into at least one eye of the test subject and determining a visual acuity limit diopter associated with the predetermined visual acuity of the target, the method comprises determining a best refraction (target refraction) of the at least one eye of the test subject. In particular, the method can comprise determining an objective refraction and / or a subjective refraction or an objective refraction result and / or a subjective refraction result. Determining the best refraction can also comprise determining a combined refraction or a combined refraction result based on the objective refraction measurement and / or the subjective refraction measurement, wherein in particular also other data of the at least one eye of the test subject are considered such as lower order and / or higher order aberrations from an aberrometer or other biometric data such as corneal shape, lens to retina distance, anterior chamber depth, etc. In this sense, the term "refraction" and "target refraction" (or "refraction result") are not intended to be limited to a correction degree of lower order aberrations (e.g. spherical aberration and astigmatism aberration) but they can also include higher order aberrations. Thus, the term "refraction" can also be generally understood as "correction degree". Preferably, the best refraction of the at least one eye of the test subject is determined in a blurred state, which can be achieved by providing or projecting a corresponding target into the at least one eye of the test subject (see above). Furthermore, according to this preferred embodiment, the visual acuity reached by the at least one eye of the test subject is determined when a possible refractive error of the at least one eye of the test subject is compensated (e.g. based on the determined best refraction). In other words, once the refractive error determined by the refraction measurement has been substantially corrected by means of the optical system or by means of the lens, i.e. the visual acuity with correction (VAcc), the visual acuity is determined, the effect of which corresponds to the determined refraction result. The visual acuity can be determined using known methods. In particular, the determined best refraction and the measured related visual acuity represent one pair of at least two visual acuity and refraction values provided, which are used or considered in determining the sensitivity. In this way, the determination of the sensitivity can be combined with or integrated into the measurement of the objective refraction and / or the subjective refraction. Thus, the sensitivity can be determined in a fast and simple manner, in particular in combination with other measurements.

[0108] In another preferred embodiment, preferably after the target configured to verify a predetermined visual acuity is projected into the at least one eye of the test subject and after the visual acuity limit diopter associated with the predetermined visual acuity of the target is determined, the method additionally comprises the following steps:

[0109] - determining a subjective refraction result or a subjective refraction of the at least one eye of the test subject;

[0110] - determining a visual acuity reached by the at least one eye of the test subject based on the determined subjective refraction result, while compensating for possible refractive errors of the at least one eye of the test subject.

[0111] The determined subjective refraction and the visual acuity of the at least one eye of the test subject determined at the determined subjective refraction preferably represent one pair (or another pair, in particular a second pair, a third pair, a fourth pair, etc.) of the pairs of visual acuity and refraction values provided by the method for determining the sensitivity.

[0112] Furthermore, the method preferably comprises determining a best refraction of the at least one eye of the test subject based on the subjective refraction result and the objective refraction result. The best refraction is in particular a combined refraction resulting from the subjective and objective refraction results. Determining a combined refraction result from an objective refraction measurement and a subjective refraction measurement is known in principle and will therefore not be explained in more detail in the context of the present specification. For example, the combined refraction can be determined because the objective refraction measurement is performed first and the objective refraction result is adjusted by means of the subsequently performed subjective refraction. In particular, the combined refraction can also be determined by forming an average of the objective refraction and the subjective refraction.

[0113] In another preferred embodiment, the sensitivity is determined based on at least one calculated pseudo-refraction, wherein the at least one calculated pseudo-refraction is calculated based on the determined best refraction. In this case, the best refraction can be the determined objective refraction and / or the subjective refraction. The best refraction can in particular represent a combined refraction resulting from the objective and subjective refractions.

[0114] The pseudo-refraction is preferably determined “post factum”, i.e. only after a target configured to verify a predetermined visual acuity has been projected into the at least one eye of the test subject and after a visual acuity limit refraction associated with the predetermined visual acuity of the target has been determined. The pseudo-refraction is preferably determined only after the at least one pair of visual acuity and refraction values has been determined. Preferably, the pseudo-refraction is determined after the objective refraction measurement and / or the subjective refraction measurement has been performed and in particular after a desired refraction or a desired refraction result has been determined from the objective refraction measurement and the subjective refraction measurement. For example, in a preferred embodiment, the following steps can be performed, in particular in the stated sequence:

[0115] 1 ) performing an objective refraction measurement (as part of the method according to the application);

[0116] 2) determining at least one pair of visual acuity and refraction values (as part of the method according to the application);

[0117] 3) performing a subjective refraction measurement;

[0118] 4) determining an ideal refraction or an ideal refraction result from the objective refraction measurement and the subjective refraction measurement; and

[0119] 5) calculating the pseudo-refraction and the acuity from the result of step 4, i.e. based on the determined ideal refraction or the determined ideal refraction result.

[0120] In another preferred embodiment, changing the target refraction comprises monotonously decreasing the target refraction and / or monotonously increasing the target refraction.

[0121] In another preferred embodiment, the visual acuity limit refraction of the at least one eye of the test subject associated with the predetermined visual acuity is determined by decreasing the target refraction and detecting a test subject action while decreasing the target refraction, and / or by increasing the target refraction and detecting a test subject action while increasing the target refraction, wherein each test subject action causes a determinable change in the identifiability of the target of the test subject at the respective test subject action. In this way, the “out-of-focus point” is approached from different directions. In other words, one out-of-focus point can be determined when increasing the target refraction, while another out-of-focus point can be determined when decreasing the target refraction. These out-of-focus points can differ from each other and can be averaged subsequently. In particular, the acuity can be determined from the two out-of-focus points by means of known metrics as part of a least squares method.

[0122] In another preferred embodiment, at least two of the provided pairs of visual acuity and refraction values are provided by the following steps:

[0123] - projecting a first target having a first adjustable and / or variable target refraction into the at least one eye of the test subject, wherein the first target is configured to verify a predetermined (predefined and / or known) first visual acuity (or a predetermined first level of visual acuity);

[0124] - determining a first visual acuity limit refraction of the at least one eye of the test subject associated with the predetermined first visual acuity (or the predetermined first level of visual acuity) by changing (in particular continuously, monotonously and / or constantly changing) the first target refraction of the first target projected into the at least one eye of the test subject and detecting a signal or a determination of a first test subject action that causes a change in the identifiability of the first target of the test subject at the first test subject action;

[0125] - projecting a second target having a second adjustable and / or variable target dioptric power into the at least one eye of the test subject, wherein the second target is configured to verify a predetermined (predefined and / or known) second visual acuity (or a predetermined second visual acuity level) different from the predetermined first visual acuity (or the predetermined first visual acuity level);

[0126] - determining a second visual acuity limit dioptric power of the at least one eye of the test subject associated with the predetermined second visual acuity (or the predetermined second visual acuity level) by changing (in particular continuously, monotonously and / or constantly changing) the second target dioptric power of the second target projected into the at least one eye of the test subject and detecting a second test subject action, which second test subject action causes a signal or a determination that the identifiability of the second target by the test subject has changed at the time of the second test subject action.

[0127] In particular, the sensitivity of the at least one eye of the test subject is determined using or taking into account the predetermined first visual acuity and the determined associated first visual acuity limit dioptric power and, in addition, using or taking into account the predetermined second visual acuity and the determined associated second visual acuity limit dioptric power. Preferably, the first predetermined visual acuity or the first predetermined visual acuity level of the first target is smaller than the second predetermined visual acuity or the second predetermined visual acuity level of the second target. For example, the first predetermined visual acuity or the first predetermined visual acuity level can have a value of 0.8 logMar, while the second predetermined visual acuity or the second predetermined visual acuity level can have a value of 1.0 logMar. Alternatively, for example, the first predetermined visual acuity or the first predetermined visual acuity level can have a value of 0.4 logMar, while the second predetermined visual acuity or the second predetermined visual acuity level can have a value of 0.8 logMar or 1.0 logMar. It goes without saying that other values can also be chosen. The change in the predetermined visual acuity or the predetermined visual acuity level from one virtual target to the next target is preferably in the range of 0.2 logMar to 0.7 logMar, preferably in the range of 0.2 logMar to 0.5 logMar, and particularly preferably in the range of 0.2 logMar to 0.3 logMar.

[0128] In another preferred embodiment, determining the visual acuity limit diopter comprises measuring and / or monitoring the accommodation status of at least one eye of the test subject, wherein measuring the accommodation status is performed in particular at least at or immediately after the test subject's action. The results of this type of measurement or monitoring can be used to control the progress (e.g. terminate or repeat individual steps in case of an undesired accommodation (e.g. a value below a certain threshold) occurs). The measurement can be performed not only continuously but also only at or immediately after the test subject's action. Furthermore, the measured accommodation status (spherical aberration, cylindrical aberration, low-order aberration or high-order aberration) that is ideally measured at the time of the test subject's action can be included in the calculation of the sensitivity or the pseudo- diopter. For example, the distance value of the applied effect can be subtracted from the hyperopic diopter value. Formulated in equations, the following equation applies to the simplest case: the sensitivity represents the visual acuity V as a function of the pseudo-diopter F, i.e. V = f(F). Here, the pseudo-diopter F is

[0129] - the difference between the actual applied effect T and the ideal effect I in the case of no accommodation, i.e. F = T - I; and

[0130] - the difference between the actual applied effect T and the currently measured effect G a in the case of accommodation, i.e. F = T - G a .

[0131] When there is a deviation D between the ideal effect I and the measured effect at the relaxed eye (effect G0), the following equation applies: I = G0+ D. Thus, in this case, F = T - (G0+ D) and F = T - (G a + D). For the spherical value, this formula can be used in the manner described. For the cylindrical value, the cross-cylinder formula should be used accordingly. Zernike coefficients (also for high-order aberrations) or power vectors can be used analogously.

[0132] Alternatively or additionally, determining the visual acuity limit diopter comprises measuring and / or monitoring the pupil size (e.g. pupil radius) of at least one eye of the test subject, wherein measuring the pupil size is in particular performed at least at or immediately after the test subject’s action. The pupil size can be measured, for example, by means of a camera which is a component of an autorefractor or an aberrometer or by means of a separate camera. When determining the sensitivity of at least one eye of the test subject to defocus, the pupil size measured at the test subject’s action (i.e. at the point of defocus) or, respectively, immediately before or after (e.g. 2 seconds before reaching the point of defocus) can be used. In particular, by means of a suitably parameterized eye model and a known additional blurring, the measured pupil size can be used to quantify the defocus of the image on the retina, preferably. A simpler description can also be used instead of a complete eye model. For example, an angle can be calculated at which a disk of confusion of the point of defocus can be observed in a given pupil and in the case of a given additional blurring (see, for example, WO 2019034525 A1). As a component of such a visual acuity model, the sensitivity can be determined as a deterioration of the visual acuity per angle disk of confusion.

[0133] In another preferred embodiment, the test subject is presented with a visual task having at least two, preferably at least three, particularly preferably at least four, in particular four or eight, possible different answers in order to determine the visual acuity limit diopter, wherein the test subject can answer the visual task by means of the test subject’s action. Here, a “visual task” is in particular understood as a task having a predetermined and thus verifiable solution. In particular, the visual task is thus a verifiable task (i.e. the solution is known and thus verifiable). In other words, the behavior of the test subject is not just a communication of the recognizable or identifiable nature of the target. The visual task is preferably based on a “forced choice”, i.e. the test subject is “forced” to make a selection from a plurality or at least two or more possible answers, wherein the correct answer is preferably predetermined or known. In the context of the present application, such a visual task is referred to as a “forced choice” visual task. The visual task can be solved or, for example, a selection can be made by means of a joystick with which the test subject can activate different directions. For example, the visual task can comprise that the test subject has to identify the position or direction of an intermediate gap in an optotype by means of a joystick. For example, if the optotype is a Landolt ring, there are eight possible positions and thus eight possible answers for the test subject. It goes without saying that other optotypes can also be used in principle, so that the test subject has, for example, two, three, four, five, six, seven, etc. possible answers. This makes the method more accurate and reliable than if the test subject only has to give an unverified reaction (e.g. “yes” or “no”, or “recognizable” or “unrecognizable”).

[0134] In another preferred embodiment, prior to the step of determining the visual acuity limit diopter, first aberration data of the at least one eye of the test subject are acquired, preferably for a distance accommodation state and / or a blur state of the at least one eye of the test subject, especially at a first luminance. Moreover, the method preferably comprises acquiring second aberration data of the at least one eye of the test subject for a near accommodation state of the at least one eye of the test subject, especially at a second luminance whose value is lower than the value of the first luminance. Here, the acquisition of the second aberration data preferably takes place prior to the step of determining the visual acuity limit diopter. In the context of the present specification, “aberration data” (or “aberration measurement”) is understood to mean data (measurements for obtaining these data) for describing the eye aberration, when expressed in Zernike coefficients, whose information content corresponds at least to the terms of the “defocus” level, but ideally includes higher orders (e.g. coma and spherical aberration). Especially, the “aberration data” can also include or be (pure) auto refraction data. Especially, the acquisition of the aberration data also includes the acquisition of (pure) auto refraction data (i.e. sphere and / or cylinder and / or axis). The luminance in the intermediate vision mode is preferably provided as the first luminance and the second luminance (preferred optical densities in the range of approximately 0.003 cd / m 2 to approximately 30 cd / m 2 , in particular preferably in the range of approximately 0.003 cd / m 2 to approximately 3 cd / m 2 , more preferably in the range of approximately 0.003 cd / m 2 to approximately 0.3 cd / m 2 , more preferably in the range of approximately 0.003 cd / m 2 to approximately 0.03 cd / m 2 . The luminance is especially always understood to mean the luminance at the position of the eye or the luminance detected by the eye.

[0135] In conjunction with the acquisition of the first aberration data and / or the acquisition of the second aberration data (i.e. especially at the first luminance and / or the second luminance and in the first accommodation state and / or the second accommodation state), first pupil measurement data and / or second pupil measurement data of the at least one eye of the test subject can also be acquired. Here, the term “pupil measurement data” (or pupil measurement value) refers to information about the pupil size (or measurements for obtaining these data), which includes at least one size indication (e.g. in the form of a radius), but can also reproduce the shape of the pupil in a more complex form. Moreover, the pupil measurement data can contain information about the position of the pupil (e.g. relative to the vertex of the cornea or the optical axis of the eye).

[0136] Another aspect to solve the problem relates to a method for calculating, optimizing or evaluating an ophthalmic lens for at least one eye of a test subject or of an eyeglasses wearer taking into account the sensitivity of the at least one eye of the test subject, wherein the sensitivity of the at least one eye of the test subject is determined by the method of the application described herein.

[0137] In particular, the method for calculating, optimizing or evaluating an ophthalmic lens for at least one eye of a test subject comprises the following steps:

[0138] a) providing an assignment of at least one imaging property or aberration of an ophthalmic lens system to a visual acuity of an eyeglasses wearer or of an average eyeglasses wearer when observing an object through the ophthalmic lens system;

[0139] b) determining or specifying an objective function of the ophthalmic lens to be calculated or evaluated, wherein the assignment from step (a) is to be evaluated;

[0140] c) calculating or evaluating the ophthalmic lens to be calculated or evaluated by evaluating the objective function, wherein the objective function is evaluated at least once.

[0141] The assignment of the at least one imaging property or aberration of the ophthalmic lens system to the visual acuity of the eyeglasses wearer can depend parametrically on the measured output visual acuity and / or on the measured sensitivity of the eyeglasses wearer. The calculation and / or optimization of the ophthalmic lens can in particular comprise minimizing or maximizing the objective function. The method for calculating, optimizing or evaluating the ophthalmic lens can additionally comprise calculating the light beam exiting from the object in at least one observation direction by means of wavefront calculation, beam calculation or wavefield calculation through the ophthalmic lens system and / or through the ophthalmic lens to be calculated or evaluated up to an evaluation surface in the ophthalmic lens system. Furthermore, the method for calculating, optimizing or evaluating the ophthalmic lens can comprise calculating a difference of the light beam exiting from the object at the evaluation surface and a reference light beam converging on the retina of a model eye and determining the at least one imaging property or aberration based on the calculated difference. Preferably, the at least one light beam exiting from the object is calculated by means of wavefront calculation, wherein calculating the difference at the evaluation surface comprises calculating a wavefront difference between the wavefront of the light beam exiting from the object and the wavefront of the reference light beam converging on the retina, wherein the wavefront difference is calculated at the evaluation surface. Furthermore, the method for calculating, optimizing or evaluating the ophthalmic lens can comprise assigning a geometrical optics angle and / or a quadratic form in a geometrical optics angle space to the calculated wavefront difference, wherein the at least one imaging property or aberration depends on the geometrical optics angle and / or at least one component of the quadratic form.

[0142] Alternatively or additionally, the method for calculating, optimizing or evaluating the ophthalmic lens can comprise the following steps:

[0143] - specifying a first surface and a second surface for the ophthalmic lens to be calculated or optimized;

[0144] - determining a route of the chief ray through at least one surface of the ophthalmic lens to be calculated or optimized into the model eye;

[0145] - evaluating a wavefront aberration resulting from the chief ray incident onto the first surface of the ophthalmic lens compared to a wavefront converging on a point on the retina of the model eye;

[0146] - iteratively changing the at least one surface of the ophthalmic lens to be calculated or optimized until the evaluated aberration corresponds to the predetermined target aberration.

[0147] Another aspect solving this problem relates to a method of manufacturing an ophthalmic lens, comprising:

[0148] - calculating or optimizing an ophthalmic lens according to the method for calculating or optimizing an ophthalmic lens according to the present application; and

[0149] - manufacturing the ophthalmic lens calculated or optimized in this way.

[0150] Moreover, the present application provides a computer program product, in particular in the form of a storage medium or a data stream, containing program code configured to perform the method according to the present application, in particular for determining the sensitivity of at least one eye of a test subject and / or for calculating, optimizing or evaluating an ophthalmic lens and / or for manufacturing an ophthalmic lens, when loaded and executed on a computer. In other words, the present application provides a computer program product comprising machine-readable program code adapted to perform the above-mentioned method according to the present application when the code is loaded onto a computer. In particular, the computer program product is understood to be a program stored on a data medium. In particular, the program code is stored on a data medium. In other words, the computer program product comprises computer-readable instructions which, when loaded into the memory of a computer and executed by the computer, cause the computer to perform the method according to the present application.

[0151] In particular, the present application provides a computer program product containing program code designed and configured to perform the method according to the present application for determining the sensitivity of at least one eye of a test subject and / or the method according to the present application for calculating, optimizing or evaluating an ophthalmic lens and / or the method according to the present application for manufacturing an ophthalmic lens, when loaded and executed on a computer.

[0152] Another independent aspect solving this problem relates to a device for determining the sensitivity of at least one eye of a test subject, comprising:

[0153] - a target providing device for providing a target configured to verify a predetermined visual acuity;

[0154] - an optical system for projecting a target having a target refractive power into at least one eye of the test subject, wherein the optical system is configured to adjust and vary the target refractive power;

[0155] - a feedback unit for detecting a test subject action in order to determine that the identifiability of the target of the test subject has changed when the test subject action, in particular as a result of varying the target refractive power of the target projected into at least one eye of the test subject with the aid of the optical system;

[0156] - a visual acuity limit refractive power determination unit for detecting a visual acuity limit refractive power of at least one eye of the test subject associated with a predetermined visual acuity, wherein the visual acuity limit refractive power determination unit is configured to detect, in particular determine and store, the target refractive power caused by the optical system when the test subject action.

[0157] The target providing device can for example comprise an electronic display or digital screen. In particular, the display can be configured such that individual pixels of the display, different regions or different components of the display can be individually excited, in particular to display the compiled optotypes. For example, sub-segments of a ring can be displayed, using which a Landolt C optotype with differently oriented openings can be generated or displayed. Alternatively or additionally, complete optotypes, such as letters or numbers, can also be formed as a whole, in particular switchable LCD elements.

[0158] The target providing device can for example comprise a flip mechanism, a displacement mechanism or a rotation mechanism, which is for example magnetic or electric, using which different targets or images can be displayed and / or replaced. The targets and images can also be partially transparent and only contain the area that should be displayed in addition to another image.

[0159] The transparent backlit images can also be configured such that certain components of the image are only visible when one or more specific light sources, for example additional shadow areas or with a specific wavelength, are switched on or off.

[0160] The optical system is in particular arranged between at least one eye of the test subject and the target providing device or the provided target. The optical system is configured to apply or produce different target effects and thus to influence the identifiability of the target by at least one eye of the test subject. In the simplest case, the optical system is configured to apply various spherical effects. This can for example be achieved by arranging one or more spherical lenses, such as in the form of a Badal system. Alternatively or additionally, one or more adaptive lenses can be used or arranged, optionally in combination with conventional lenses. In a more complex case, in addition to or instead of spherical effects, the optical system can be configured to apply or produce various cylindrical effects or effects of higher order.

[0161] The optical system can comprise at least one lens with a spherical effect and / or at least one lens with a cylindrical effect. For example, the optical system can comprise a cartridge comprising a plurality of spherical lenses and / or cylindrical lenses, each spherical lens and / or cylindrical lens having a different spherical or cylindrical effect, and wherein the cartridge is configured and arranged such that a single spherical lens or a single cylindrical lens and / or a combination of a plurality of spherical lenses or cylindrical lenses from the cartridge can be selected and used to project the target. The optical system may, for example, also comprise an Alvarez lens system. In other words, the target of the test subject (or projected or virtual target) through which the test subject sees the target or virtual target. The optical system may, for example, also comprise two lenses that are rotatable relative to each other, and each lens has at least one cylindrical component in effect. In particular, the optical system can comprise two cylindrical lenses comprising rotationally symmetric surfaces, preferably planar surfaces, which face each other and interlock. The optical system can also comprise a positive cylindrical lens and a negative cylindrical lens with the same but opposite effects, which are mounted so that they can be rotated relative to each other and, preferably, movable relative to each other.

[0162] Furthermore, when applying different effects by means of the optical system, the perspective of the target can change. This can be prevented by a suitable construction of the optical system, or can be determined by the computer and compensated for when displaying. To this end, it is necessary to determine the perspective based on the effect applied, and it is necessary to assign a visual acuity value based on this actual perspective, which can be achieved, for example, by determining the magnification of the optical system and displaying the target in a correspondingly reduced manner. Alternatively, the optical system can be calibrated by means of a camera, since the size of the target can be implemented directly by a camera arranged at the point of at least one eye of the test subject (and looking towards the optical system).

[0163] In principle, the feedback from the test subject or test subject action can be verbal. In this case, the user can record the feedback or the state of the optical system at the time of the test subject action, and / or pass the feedback directly to the feedback system. However, this variant is prone to errors and promotes delays. This is why direct feedback from the test subject to the feedback system is preferred. To this end, the feedback system can comprise a button in the simplest case. In another preferred embodiment, the feedback system can also comprise two buttons ("+" and "-"), three buttons ("+", "-", and "OK"), four buttons (for example, "+", "-", "OK", and "cancel"), etc., and / or can comprise a joystick. Alternatively or additionally, the feedback system can comprise a microphone for capturing verbal comments from the test subject.

[0164] In a preferred embodiment, the device comprises an evaluation unit for determining the sensitivity of the at least one eye of the test subject based on the provided at least two visual acuity and refraction values. In this case, the visual acuity limit refraction determination unit can be a component of the evaluation unit. In other words, the evaluation unit can comprise the visual acuity limit refraction determination unit.

[0165] In another preferred embodiment, the device comprises an autorefraction or aberrometry unit for determining one or more objective refractions of the at least one eye of the test subject, wherein the autorefraction or aberrometry unit is preferably configured to measure and / or monitor the accommodation state of the at least one eye of the test subject. Further, the autorefraction or aberrometry unit can comprise a camera for determining the pupil size, in particular the pupil radius, of the at least one eye of the test subject. Alternatively or additionally, the autorefraction or aberrometry unit can comprise a calibration camera for calibrating the optical system. The camera for determining the pupil size and the calibration camera can also be implemented in a single camera which combines both functions (determining the pupil size and calibrating the optical system).

[0166] In another preferred embodiment, the device comprises a pupil size measurement unit, in particular a camera, for determining the pupil size, in particular the pupil radius, of the at least one eye of the test subject. Alternatively or additionally, the device can comprise an illumination device for generating at least two luminance levels. Alternatively or additionally, the device can comprise a pupillometer device configured to detect first pupillometer data of the at least one eye at a first luminance and to detect second pupillometer data of the at least one eye at a second luminance.

[0167] Another aspect of the solution relates to a device for calculating, optimizing or evaluating an ophthalmic lens for the at least one eye of a test subject taking into account the sensitivity of the at least one eye of the test subject, comprising a device for determining the sensitivity of the at least one eye of the ophthalmic lens wearer according to the application.

[0168] The device for calculating, optimizing or evaluating an ophthalmic lens can in particular comprise the following components:

[0169] - a surface model database for specifying a first surface and a second surface of the ophthalmic lens to be calculated or optimized;

[0170] - a chief ray determination module for determining a route of a chief ray through at least one point of view of at least one surface of the ophthalmic lens to be calculated or optimized into a model eye;

[0171] - an evaluation module for evaluating a wavefront aberration produced along the chief ray from a spherical wavefront impinging on the first surface of the ophthalmic lens at an evaluation surface compared to a wavefront converging on a point on the retina of the eye model; and

[0172] - an optimization module for iteratively changing at least one surface of the spectacle lens to be calculated or optimized until the assessed aberration corresponds to the predetermined target aberration.

[0173] Another aspect that solves the problem relates to an apparatus for manufacturing a spectacle lens, comprising:

[0174] a calculation or optimization device configured to calculate or optimize a spectacle lens according to the method for calculating or optimizing a spectacle lens according to the invention; and

[0175] a processing device configured to process the spectacle lens according to the result of the calculation or optimization.

[0176] Another aspect that solves the problem relates to a spectacle lens manufactured by means of the method for manufacturing a spectacle lens according to the invention and / or by means of the apparatus for manufacturing a spectacle lens according to the invention.

[0177] Furthermore, the invention provides the use of a spectacle lens manufactured according to the manufacturing method according to the invention, especially in a predetermined average or customized use position in front of the eye of a spectacle wearer, for correcting the refractive error of the spectacle wearer, especially in the preferred embodiments.

[0178] In particular, the computer-implemented method according to the invention can be provided in the form of an ordering software and / or an industrial software. In particular, the data required for calculating and / or optimizing and / or manufacturing a spectacle lens can be acquired and / or transmitted by means of such a method.

[0179] The apparatus according to the invention and / or the system according to the invention, for example for ordering a spectacle lens, can in particular comprise a computer and / or a data server configured to communicate via a network, for example the Internet. According to the invention, the computer is in particular configured to carry out a computer-implemented method, for example an ordering software for ordering at least one spectacle lens, and / or a transmission software for transmitting the relevant data, and / or a determination software for determining the relevant data, and / or a calculation or optimization software for calculating and / or optimizing a spectacle lens to be manufactured.

[0180] It goes without saying that the features described above and below can not only be used in the combinations stated, but also on their own or in other combinations.

[0181] The above or below comments made with respect to the embodiments of the first aspect also apply to the other independent aspects described above, in particular to the preferred embodiments of this aspect. In particular, the above or below comments made with respect to the embodiments of the other independent aspects also apply to one independent aspect of the invention and to the preferred embodiments of this aspect.

[0182] The various embodiments for solving this problem are described below by way of example with reference to the accompanying drawings. In this case, the various embodiments described sometimes contain features that are not absolutely necessary for the reproduction of the claimed subject matter, but in certain applications provide desirable properties. Embodiments that do not contain all the features of the embodiments described below should therefore also be considered as disclosed under the described technical teaching. Furthermore, in order to avoid any unnecessary repetition, certain features are only referred to in connection with the various embodiments described below. It should be noted that the various embodiments should therefore not only be considered in isolation, but also in combination. When considering the embodiments in combination, the person skilled in the art will note that individual embodiments can also be modified by including individual or multiple features of other embodiments. It should be noted that it can be desirable and useful to combine the various embodiments systematically with individual or multiple features described in connection with other embodiments, and should therefore be considered and also deemed to be covered by the description. BRIEF DESCRIPTION OF DRAWINGS

[0183] Figure 1 An exemplary image or photograph is shown that gives the observer a sense of distance;

[0184] Figure 2 An image or photograph is shown from Figure 1 in which an exemplary target is integrated in the image or overlaid on the image;

[0185] Figure 3 An adaptation amplitude map as a function of age (Duane curve) is shown. DETAILED DESCRIPTION

[0186] Figure 1 An exemplary image or photograph is shown that contains a hot air balloon and a road and gives the observer a sense of distance. In the context of the present invention, the image can be projected into at least one eye of the test subject, for example as a target, in particular as a virtual target, in order to perform an objective refraction measurement, for example in a blur state in which the test subject only recognizes the details of the image or the out-of-focus image.

[0187] Figure 2 An image or photograph is shown from Figure 1an image or a photo in which exemplary optotypes are integrated in the image or overlaid on the image, i.e. different sized numbers arranged in a road sign. Each of these optotypes has a predetermined visual acuity or a predetermined visual acuity level. In the context of the method according to the application, the optotypes are provided for the image by means of the optical system with an adjustable target refraction. This target refraction is changed by means of the optical system and the test subject signals by means of the test subject action that the identifiability of the target or optotype has changed upon the test subject action. In this way, pairs of visual acuity and refraction values can be provided in order to determine the sensitivity of at least one eye of the test subject.

[0188] One or more targets can be provided to the test subject or can be projected into at least one eye of the test subject as virtual targets. According to embodiments, two or more targets can be used, which can also be identical in content.

[0189] For example, the first target can be an image giving a sense of distance (see for example Figure 1 ), the second target can be one or more optotypes of a specific size, and the third target can be one or more optotypes of a different size. Here, optotypes are understood to be all symbols, images, etc. which are identifiable by the test subject.

[0190] Alternatively, the first target can be an image giving a sense of distance, while the second and third targets can be identical in content and contain one or more optotypes, each of which has one of two sizes.

[0191] Alternatively, all three targets can be identical and represent one image which gives a sense of distance, but can contain one or more details, the identification of each of which can be assigned to a visual acuity level. These details are explicitly included in the description of the term "optotype". An example of such a detail is in an image containing, for example, a hot air balloon and a road:

[0192] - the hot air balloon and the symbols or panels on the hot air balloon basket,

[0193] - the clouds or the symbols in the clouds,

[0194] - the lines on the road, and / or

[0195] - the symbols on the road side signs.

[0196] One particularly suitable symbol is, for example, one or more concentric rings which merge together to form a circle at a given focus deficiency.

[0197] In the present invention, in contrast to the prior art, in order to determine the sensitivity, not the level of visual acuity of the specific application effect is determined, but the application effect necessary to reach a predetermined visual acuity. Furthermore, the determination of the visual acuity can be associated with an auto-refraction or with a measurement of aberration data in a non-adapted or adapted state. In one specific embodiment, also the adapted state of the eye can be tracked in order to thus obtain more reliable sensitivity values.

[0198] A. Method according to an exemplary embodiment without subjective refraction

[0199] The test on the test subjects can be performed as follows, for example:

[0200] 1) The objective refraction value of the subject is determined by means of auto-refraction or aberration measurement. To this end, a first target is presented to the test subject. In this case, a suitable optical system is used to provide the first effect to the test subject, which does not allow them to fully clearly identify the target, thus relaxing the ciliary muscles.

[0201] 2) The test subject is then provided with a second target and a second effect is applied by means of the test optical system, in which the test subject cannot identify the (one or more) optotypes with high visual sensitivity. This is achieved, inter alia, by selecting a spherical effect corresponding to the central sphere or to one of the two main sections corresponding to the objective refraction value plus an additional positive spherical effect. Thus, the latter effect, commonly referred to as "blurring", is selected, as the subject cannot compensate for this effect by adaptation. In order to determine the speed of the change of the effect provided, a standard value based on the average value of many subjects can be used. For example, it is known that the visual acuity is halved by approximately 0.5 dpt sphere and 1 dpt cylinder due to blurring. Preferably, the target refraction varies at a speed of between 1 / 16 dpt per second and 1 / 2 dpt per second. The additional spherical effect can also depend on the pupil measured by the aberrometer. For example, it can be inversely proportional to the pupil radius, so that test subjects with a smaller pupil preferably have a stronger blurring effect than test subjects with a larger pupil, to ensure that the perceived lack of focus is similar for all test subjects.

[0202] 3) Alternatively, a spherical-cylindrical effect can also be provided. For example, for an optical system from the objective refraction, a cylindrical effect can be employed and an additional positive spherical effect can be applied to the average objective refraction value. Alternatively or additionally, a shift in astigmatism can be applied to the objective refraction value (so-called astigmatic blurring). The optical effect is then slowly varied (for example, between 1 / 16 dpt per second and 1 / 2 dpt per second) towards the best or objective refraction (by changing the spherical effect and / or changing the astigmatism effect).

[0203] 4) As soon as the test subject can identify the second target's optotypes by the changed effect, they communicate this (e.g. using an "OK" button). Optionally, they can adjust the limiting effect themselves (e.g. using "+" and "-" buttons) and activate it (e.g. again using the "OK" button). The effect adjusted here when identifying the second target is stored as the "visual acuity limit effect" or "visual acuity limit diopter".

[0204] 5) The test subject is provided with a third target.

[0205] 6) Again, the optical effect is subsequently changed slowly (e.g. between 1 / 16 dpt per second and 1 / 2 dpt per second) towards the optimal or objective diopter value (by changing the spherical effect and / or the astigmatism effect).

[0206] 7) As soon as the test subject can identify the third target's optotypes by the changed effect, they communicate this (e.g. using an "OK" button). Optionally, they can adjust the limiting effect themselves (e.g. using "+" and "-" buttons) and activate it (e.g. again using the "OK" button). The effect adjusted here when identifying the third target is stored as the "visual acuity limit effect" or "visual acuity limit diopter".

[0207] The sensitivity can be determined from the visual acuity levels of the two targets, the objective diopter value, the effect when identifying the second target and the effect when identifying the third target. For this purpose, sensitivity measures can be used, inter alia, as already described above in the exemplary embodiment. Here, the pseudo diopter is produced by the spherical distance and / or the astigmatism distance of the effect when identifying the relevant target from the objective diopter value.

[0208] B. Method according to the exemplary embodiment with subjective diopter

[0209] In this variant, the above steps 5) to 7) can be omitted from the method under section A. Thus, only the visual acuity of one target and the effect when identifying the target need to be determined. The subjective diopter determination is then carried out, and in the course of this, the subjective diopter value and the visual acuity reached by the test subject thereby (visual acuity with correction (VAcc)) are determined. In the course of this, the objective diopter value can be used as a starting value for the subjective diopter determination.

[0210] Alternatively, the subjective diopter determination with the visual acuity determination can be carried out before the steps from section A. In this case, no autorefraction or aberrometry needs to be carried out, and no objective diopter value needs to be determined (step 1), and the subjective diopter value is used at this point.

[0211] Here, the pseudo-refractive power can be the spherical distance or the distance of the astigmatism from the subjective refractive value to identify the target.

[0212] Instead of the subjective refractive value, also the combined refractive value can be used to calculate the sensitivity or the pseudo-refractive power. This can be calculated based on the subjective refractive value and the objective refractive value or other data (e.g. lower or higher order aberrations from an aberrometer or other biometric data such as the shape of the cornea, the distance of the lens to the retina, the depth of the anterior chamber).

[0213] C. Adjusting the visual acuity level of the target

[0214] Furthermore, at least one visual acuity level of one or more symbols of the target can be adjusted for the test subject. This is useful, for example, if the astigmatism of the test subject cannot be compensated. Then the visual acuity level of the (virtual) target can be chosen such that the target can still be identified despite the pseudo-refractive power due to the astigmatism.

[0215] Information about the vision (e.g. visual acuity with correction or visual acuity without correction, e.g. from a subjective refraction determination) can be fed into the determination of the target size.

[0216] If the test subject still cannot identify the symbols despite the applied effect with a lower deviation from the objective, subjective or combined refractive value, the visual acuity level can be switched to a lower one and the corresponding steps can be repeated with the lower visual acuity level.

[0217] Additionally or alternatively, the findings from step 4 can be included in the determination of the visual acuity level in step 6.

[0218] To avoid that the test subject has already identified the optotypes in multiple measurements or when switching between eyes, at least one of the optotypes or symbols or details in the image can change between different measurements or when switching between eyes (e.g. rotating a Landolt ring or changing a letter or number). For this, an electronic display is of course particularly suitable as target providing device.

[0219] D. Finding the out-of-focus point and adjusting the effect by the test subject

[0220] Finding a defocus point

[0221] As an alternative to the method in the above section, the effect applied according to section A or B at the beginning (i.e. in step 2) can also be the effect that allows the target to be identified. This can be the objective, subjective or combined refractive value.

[0222] In steps 5) and 6) the applied effect is subsequently removed in a positive direction from the effect. This direction is chosen to avoid accommodation. In steps 4) and 7) the test subject subsequently signals the time at which they can no longer identify the optotypes.

[0223] If the applied effect is determined for two levels of visual acuity, similar to the method in section A, in this case the applied effect can first be determined (steps 2-4) for the higher level of visual acuity and then for the lower level of visual acuity (steps 5-7). In this way, during the approach, the pseudo- diopters increase, which means that the optotypes first become unrecognizable with more difficult recognizability (higher level of visual acuity) and then with easier recognizability (lower level of visual acuity).

[0224] Correcting (defocused) focus points

[0225] In steps 4) and 7) of the above-described embodiment, if the test subject is not sure that they have signaled the correct time or the correct applied effect, they can optionally correct the applied effect. This can be done, for example, using the "+" and "-" buttons on the feedback unit.

[0226] Adjustment of (defocused) focus points by the test subject

[0227] The test subject can also be directly asked to adjust the applied effect under which they themselves can or can no longer identify the optotypes. This can be done, for example, using the "+" and "-" buttons on the feedback unit.

[0228] Approaching (defocused) focus points from different directions

[0229] Furthermore, one defocus point can be determined when increasing and another defocus point can be determined when decreasing. These points can differ from each other and can subsequently be averaged. Alternatively, from the two defocus points the sensitivity can be determined with the aid of known metrics as part of a least squares method.

[0230] Repeated measurements

[0231] Of course, to improve the measurement accuracy of the method, the defocus points can also be determined multiple times.

[0232] Monitoring the adaptation status

[0233] During steps 3), 4), 6) and 7) of the method according to section A, or during step 3) or step 4) of the method according to section B, the adaptation state of at least one eye of the test subject can be monitored by means of an autorefractor or aberrometer unit. The results thus obtained can be used to control the progress (for example, in the case of an undesirable adaptation (for example, a value below a certain threshold), the individual steps are terminated or repeated). The measurements can be made continuously or only when a signal of recognizability is emitted.

[0234] Furthermore, the measured adaptation state (spherical aberration, cylindrical aberration, lower-order aberration or higher-order aberration), ideally when a signal of recognizability is emitted, can be included in the calculation of the sensitivity or the pseudophakia.

[0235] E. Loss of focus in the negative direction and combined with myopia measurement

[0236] Loss of focus in the negative direction

[0237] In the exemplary embodiments described above, the effect applied corresponds to a pseudophakia in the positive direction, since this cannot be compensated by the test subject by means of adaptation. The opposite case, i.e. an application effect corresponding to a pseudophakia in the negative direction, can also be implemented. The accommodation that can occur in this case can be processed in the following way:

[0238] - without taking the adaptation into account;

[0239] - measuring test subjects who are, for example, physiologically (for example, in an age-related manner) or pharmacologically (for example, by means of drops) affected or can only adapt to a poor extent;

[0240] - measuring or monitoring the adaptation state;

[0241] - making use of assumptions about the adaptation ability (for example, on the basis of age according to the Duane curve; see Figure 3 ).

[0242] The curve shown by Duane in Figure 3 is taken from B. Lachenmayr, D. Friedburg, E. Hartmann, A. Buser: "Auge - Brille - Refraktion: Schober-Kurs: verstehen - lernen - anwenden" [Eye - glasses - refraction: Schober course: understand - learn - apply], 2005, Figure 1.29, originally published in Alexander Duane: Studies of accommodation and its clinical application to cases of concomitant and convergent squint, Transactions of the American Ophthalmological Society, vol. 20, 1922, pp. 132-157, PMID 16692582, PMC 1318318. The Duane curve shows that the accommodation capacity (amplitude of accommodation) of the human eye decreases from 8 years to just over 50 years, on average from 14 diopters to 1 diopter.

[0243] Here, the influence of accommodation on the sphere can be considered by, for example:

[0244] - the accommodation value is the distance value applied from the far-seeing diopter value;

[0245] - the pseudophakia is calculated directly from the applied effect and the measured or assumed diopter value.

[0246] In a similar way, the astigmatic deviation can be calculated from the measured cylinder by means of known forms (e.g. cross cylinder formula, power vector notation) in order to take into account the astigmatic change due to accommodation. Furthermore, the measured higher order aberrations can be taken into account by means of known metrics.

[0247] Combining myopia measurements

[0248] The above-mentioned methods can be combined with the determination of the objective myopic diopter value, the maximum accommodation and / or the (lower order or higher order) aberrations.

[0249] For this purpose, the process can be as follows: the accommodation state of the eye is monitored by means of auto-refraction or aberration measurement (ideally simultaneously and as often as possible). The applied effect which allows the target to be recognized is used as a starting point. This can be an objective, subjective or combined diopter value. In steps 5) and optionally 6), the applied effect is then removed from this effect in the positive direction. In steps 4) and optionally 7), the test subject then signals the time at which they can no longer recognize the target. If the applied effect is determined for two visual acuity levels, in this case the applied effect can first be determined for the higher visual acuity level (steps 2-4) and then for the lower visual acuity level (steps 5-7). In this way, the pseudophakia increases during the approach, which means that the target first becomes unrecognizable with more difficult recognizability (higher visual acuity level) and then with easier recognizability (lower visual acuity level). The auto-refraction or aberration value measured when (each time) the signal is given that the recognizability is lost is used to calculate the sensitivity or visual acuity.

[0250] The autorefraction or the aberration measurement value corresponding to the maximum accommodation is then used as the value for the myopic refractive power or the maximum accommodation capacity (spherical aberration, cylindrical aberration, low-order aberration or high-order aberration).

[0251] F. Monitoring pupil size

[0252] In addition, the pupil size (for example, in the form of the pupil radius) can be monitored, for example, by means of a camera arranged in the autorefractor or the aberrometer, or by means of a separate camera. When determining the sensitivity to defocus, the pupil size measured at the point of defocus can be used, or correspondingly the pupil size measured before the lack of focus (for example, 2 seconds before reaching the point of defocus).

[0253] The measured pupil size can then be used to quantify the lack of focus of the image on the retina by means of a suitably parameterized eye model and the known additional blur. For example, an angle can be calculated at which the diffraction circle of the point of defocus can be observed in a given pupil and in the case of a given additional blur (see WO 2019034525 A1). As part of this visual acuity model, the sensitivity can be determined as the deterioration of the visual acuity per angle of the diffraction circle.

[0254] G. More complex sensitivity model

[0255] In a more complex model, it is possible to distinguish between the influence of the spherical blur or pseudo-refractive power and the influence of the astigmatic blur or pseudo-refractive power. For this purpose, for the same level of visual acuity, the spherical blur and the astigmatic blur can be determined.

[0256] I. Combination with other measurements

[0257] The present invention can very effectively be combined with or embedded in other measurements. In a preferred embodiment, the method according to section A or section B is carried out after an autorefraction or an aberration measurement for hyperopia. In this case, this autorefraction or aberration hyperopia measurement has already constituted the first step according to section A and does not need to be carried out again. In this case, the method according to one of the above sections can be carried out before or after any potential measurement. The advantage of the first method is that the (virtual) target is initially still unknown to the test subject and the test subject is already familiar with the target used for the myopia measurement.

Claims

1. A method for determining the sensitivity of at least one eye of a test subject based on at least two provided pairs of visual acuity and refractive power values, wherein at least one of the pairs of visual acuity and refractive power values ​​is provided by the following steps: - Projecting a target with adjustable target refractive power into at least one eye of the test subject, wherein the target is configured to verify predetermined visual acuity; and - By altering the target refractive power of the target projected onto at least one eye of the test subject and detecting the test subject's movement, a visual acuity limit refractive power of at least one eye of the test subject, associated with the predetermined visual acuity, is determined, wherein the test subject's movement causes a change in the identifiability of the target for the test subject at the time of the test subject's movement. The sensitivity is determined based on at least one calculated pseudo-refractive power, which is calculated based on the determined optimal refractive power.

2. The method according to claim 1, Prior to the step of projecting a target configured to verify predetermined visual acuity into at least one eye of the test subject, the objective and / or subjective refractive errors of the at least one eye of the test subject are determined, and The target is projected into at least one eye of the test subject with an initial target refractive power such that the test subject can only recognize the target out of focus and / or cannot recognize the target.

3. The method of claim 2, wherein the target is projected into the at least one eye of the test subject with an initial target refractive power such that the step of the test subject being able to recognize the target out of focus and / or being unable to recognize the target occurs before the step of changing the target refractive power.

4. The method according to claim 1 or 2, further comprising the following step: - Determine the optimal refractive power of the at least one eye of the test subject, and determine the visual acuity achieved by the at least one eye of the test subject when compensating for possible refractive errors of the at least one eye of the test subject based on the determined optimal refractive power.

5. The method according to claim 1 or 2, further comprising the following step: - Determine the subjective refractive error result of at least one eye of the test subject; - Determine the visual acuity achieved by the at least one eye of the test subject when compensating for possible refractive errors of the test subject based on the determined subjective refractive error results; -The optimal refractive power of the at least one eye of the test subject is determined based on the subjective and objective refractive power results.

6. The method according to claim 1 or 2, wherein changing the target refractive power comprises monotonically decreasing the target refractive power and / or monotonically increasing the target refractive power.

7. The method of claim 1 or 2, wherein the determination of the visual acuity limit refractive power of the at least one eye of the test subject associated with the predetermined visual acuity is performed by: decreasing the target refractive power while detecting a test subject action during the decrease of the target refractive power, and / or increasing the target refractive power while detecting a test subject action during the increase of the target refractive power, wherein each test subject action causes the identifiability of the target for determining the test subject to have changed at the time of the corresponding test subject action.

8. The method of claim 1 or 2, wherein at least two of the provided visual acuity and refractive power values ​​are provided by means of the following steps: - A first target having a first adjustable target refractive power is projected onto the at least one eye of the test subject, wherein the first target is configured to verify a predetermined first visual acuity; - By changing the first target refractive power of the first target projected onto the first eye of the test subject and detecting the first test subject action, the first visual acuity limit refractive power of the first eye of the test subject associated with the predetermined first visual acuity is determined, wherein the first test subject action causes the determination that the identifiability of the first target of the test subject has changed at the time of the first test subject action; - A second target having a second adjustable target refractive power is projected into at least one eye of the test subject, wherein the second target is configured to verify a predetermined second visual acuity that is different from the predetermined first visual acuity; - By changing the second target refractive power of the second target projected onto the at least one eye of the test subject and detecting the action of the second test subject, the second visual acuity limit refractive power of the at least one eye of the test subject associated with the predetermined second visual acuity is determined, the action of the second test subject causing the determination that the identifiability of the second target of the test subject has changed at the time of the second test subject action.

9. The method according to claim 1 or 2, wherein determining the visual acuity limit refractive power comprises measuring the accommodation state and / or pupil size of the at least one eye of the test subject, wherein measuring the accommodation state and / or the pupil size is performed.

10. The method according to claim 9, The measurement of the adjustment state and / or the pupil size is performed during the action of the test subject or immediately after the action of the test subject.

11. The method of claim 1 or 2, wherein the test subject is presented with a visual task having at least two potentially different answers in order to determine the visual acuity limit refractive power, and wherein the test subject is able to answer the visual task by means of the test subject's actions.

12. The method according to claim 1 or 2, Prior to determining the visual acuity limit refractive power, first aberration data of at least one eye of the test subject are obtained.

13. The method according to claim 12, Specifically, the first aberration data of the at least one eye of the test subject is obtained based on the distance adjustment state of the at least one eye of the test subject.

14. The method according to claim 12, The method further includes acquiring second aberration data of the at least one eye of the test subject in the near accommodation state.

15. The method according to claim 14, The acquisition of the second aberration data occurs prior to the step of determining the visual acuity limit refractive power.

16. A method for calculating, optimizing, or evaluating spectacle lenses for at least one eye of a test subject, taking into account the sensitivity of at least one eye of the test subject, wherein the sensitivity of the at least one eye of the test subject is determined by the method according to any one of the preceding claims.

17. A method for manufacturing spectacle lenses, comprising: - Calculate or optimize eyeglass lenses according to the method for calculating or optimizing eyeglass lenses as described in claim 16; as well as - To manufacture eyeglass lenses calculated or optimized in this way.

18. A computer program product comprising program code adapted and configured to perform the method according to any one of the preceding claims when loaded and executed on a computer.

19. An apparatus for determining the sensitivity of at least one eye of a test subject, comprising: - Target providing device for providing a target configured to verify a predetermined visual acuity; - An optical system for projecting the target having a target refractive power into at least one eye of the test subject, wherein the optical system is configured to adjust and change the target refractive power; - Feedback unit, used to detect the action of the test object in order to determine that the identifiability of the target of the test object has changed when the test object takes action; - A visual acuity limit refractive power determination unit for detecting the visual acuity limit refractive power of at least one eye of the test subject associated with the predetermined visual acuity, wherein the visual acuity limit refractive power determination unit is configured to detect the target refractive power caused by the optical system during the action of the test subject; and - An evaluation unit configured to determine the sensitivity based on at least one calculated pseudo-refractive power, the at least one calculated pseudo-refractive power being calculated based on the determined optimal refractive power of the at least one eye of the test subject.

20. The apparatus of claim 19, wherein the feedback unit is configured to detect a test subject's movement in order to determine that the identifiability of the target of the test subject has changed during the test subject's movement, as a result of changing the target refractive power of the target projected onto the at least one eye of the test subject with the aid of the optical system.

21. The device of claim 19, wherein the evaluation unit is configured to determine the sensitivity of the at least one eye of the test subject based on at least two provided visual acuity and refractive power values, and wherein the visual acuity limit refractive power determination unit is a component of the evaluation unit.

22. The apparatus according to any one of claims 19 to 21, further comprising: - An automatic refraction or aberration measurement unit for determining one or more objective refractive errors of at least one eye of the test subject.

23. The device of claim 22, wherein the automatic refraction or aberration measurement unit is configured to measure and / or monitor the accommodation state of at least one eye of the test subject.

24. The device according to any one of claims 19 to 21, further comprising: - A pupil size measurement unit for determining the pupil size of at least one eye of the test subject; and / or - Lighting equipment for generating at least two brightness levels, and / or - A pupillometer device configured to detect first pupillometer data of the at least one eye at a first brightness, and to detect second pupillometer data of the at least one eye at a second brightness.

25. A system for calculating, optimizing, or evaluating spectacle lenses for at least one eye of a test subject, taking into account the sensitivity of at least one eye of the test subject, the system comprising a device for determining the sensitivity of at least one eye of a spectacle wearer according to any one of claims 19 to 24.

26. An apparatus for manufacturing spectacle lenses, comprising: - A computing or optimization device, the computing or optimization device being configured to calculate or optimize the spectacle lens according to the method for calculating or optimizing spectacle lenses according to claim 16; as well as - A processing device configured to process the spectacle lens based on the result of the calculation or optimization.

27. An eyeglass lens, said eyeglass lens being manufactured by means of the method according to claim 17 and / or by means of the apparatus according to claim 26.

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