WO2007020333A1

WO2007020333A1 - Method of objectively determining a binocular performance criterion of a human or animal subject

Info

Publication number: WO2007020333A1
Application number: PCT/FR2005/002097
Authority: WO
Inventors: Nicolas Chateau; Xavier Jean-Francois Levecq
Original assignee: Imagine Eyes
Priority date: 2005-08-18
Filing date: 2005-08-18
Publication date: 2007-02-22

Abstract

The invention relates to a method of objectively determining a binocular visual performance criterion of a human or animal subject and to a device for performing said method. The inventive method comprises the following steps consisting in: objectively measuring the ocular aberrations of each eye (11g, 11d); using said measured aberration values to calculate two left and right eye monocular performance criteria (12g, 12d), said criteria being characteristic functions respectively of the imaging performance of each left and right eye; and calculating (13) the binocular visual performance criterion of the subject using a summation function for summing said left and right monocular performance criteria.

Description

Method for objectively determining a binocular performance criterion of a human or animal subject

The invention relates to a method for objectively determining a binocular visual performance criterion of a human or animal subject, as well as a device for implementing the method. The invention is generally in the field of visual examination, that is to say the measurement of refractive errors and visual performance of a subject.

Traditionally, visual performance measures use psychophysical methods. These methods have the particularity of being based on the patients' responses to visual stimulation; they are also called subjective.

Thus, the most commonly used visual performance criterion in clinical practice, visual acuity, is most often assessed using standardized optotype charts (letters or shapes) of different sizes. The survey of the size of the smallest optotypes recognized by a patient makes it possible to quantify his visual acuity. Another visual performance criterion, contrast sensitivity (CSF for Contrast Sensitivity Function in English), is evaluated in a similar way using an array of optotypes of different contrasts. The contrast sensitivity is obtained by determining, from the patient's answers, the least contrasted optotypes that the patient is able to distinguish.

An advantage of the subjective methods of visual examination described above is that they can be performed in binocular vision, that is to say in situations where the patient can use both eyes to see the tests presented to him. Subjective measures of visual performance also have the advantage of being sensitive not only to the optical defects of the eye, but also to possible deficiencies. - O -

in some cases, screening.

Unfortunately, these psychophysical methods of characterizing vision also have several disadvantages related to their subjectivity. In particular, they can not be used with young children, with people with learning or communication difficulties, or with animals used for research. The time spent on the exam is long; therefore, only a small number of parameters are measured. Reproducibility of measurements is generally poor. In addition, subjective measures of visual performance can not determine the exact origin of various visual disturbances. The optics of the eye is not always the cause of these problems. Indeed, if the visual performance of a patient strongly depends on the optical performance of his eyes, several other factors can contribute to significantly deteriorate the quality of his vision. The visual results obtained psychophysically can be altered not only by optical aberrations, but also by neurosensory deficiencies, difficulties of cognition, a poor psychological state of the patient (stress, fatigue, etc.), inadequate measurement conditions ( insufficient lighting _/ etc.). When the clinician reports a poor visual performance, the subjective measure does not allow him to know which of these factors is the cause.

Progress continues in the field of psychophysical assessment of vision. Different methods exist to measure visual acuity, - contrast sensitivity, modulation transfer function of the eye as well as other useful criteria. However, these psychophysical methods are based on patient responses and suffer from the limitations mentioned above. The invention provides an objective method for determining binocular visual performance criteria of a subject, such as binocular visual acuity, binocular contrast sensitivity, binocular retinal imaging simulation of an object.

For this, the proposed method uses objective measurements of the optical aberrations of each eye to deduce for each eye a monocular performance criterion characteristic of the imaging performance of said eye, a summation function being applied to both criteria. to derive a binocular performance criterion.

More specifically, the invention relates to a method for objectively determining a binocular visual performance criterion of a human or animal subject, comprising:

the objective measurement of the ocular aberrations of each eye, the calculation from the measured values of the aberrations of a monocular performance criterion for each of the left and right eyes, said criteria being characteristic functions of the imaging performance respectively of each left and right eye; - calculating the binocular visual performance criterion of the subject, by a summation function of said left and right monocular performance criteria.

Advantageously, the monocular performance criterion is the optical transfer function of the eye, calculated from said aberrations, and realigned by ^application of a function of lateral spatial shift.

The invention further relates to a device for implementing the method. It includes an objective measurement system of the ocular aberrations of an eye, a processing unit allowing in particular the calculation, at from the measured values, the aberrations of each of the two monocular performance criteria characteristic of the retinal imaging of each eye, and the calculation of the binocular visual performance criterion of the subject, by a summation of said left and right monocular performance criteria.

Advantageously, the measurement of optical aberrations is made with an objective aberrometer, of the type described in French patent application FR 0111112, which measures the monochromatic optical defects of the entire ocular structure. These defects are called ocular wavefront aberrations. The aberrometer thus makes it possible to measure not only the spherical and cylindrical optical defects, but also the monochromatic optical aberrations of higher orders of the eye taking into account the effects of the internal structure of the eye.

In addition to the objective determination of binocular visual performance obtained, the method according to the invention alternatively allows the determination of performance as a function of the distance at which the patient looks (viewing distance), corresponding to a given accommodation stimulation.

Other advantages and characteristics of the invention will appear on reading the description which follows, illustrated by the figures which represent:

FIG. 1, a diagram illustrating the steps of the method of objective determination of a binocular visual performance criterion according to the invention;

FIGS. 2A to 2C are diagrams illustrating by examples the shapes of contrast sensitivity curves respectively for the left eye, for the right and binocular eyes, obtained by the method according to the invention; FIGS. 3A to 3C are diagrams illustrating, by examples, retinal images calculated respectively for the left eye, for the right and binocular eyes, obtained by the method according to the invention;

FIG. 4 is a diagram illustrating the steps of the method of objective determination of a binocular visual performance criterion according to the invention, taking into account the distance of vision of the subject.

FIGS. 5A and 5B, diagrams showing according to two exemplary embodiments, devices for implementing the method. In these figures, the identical elements are referenced by the same references.

FIG. 1 shows a diagram illustrating the steps of the objective determination method of a binocular visual performance criterion according to the invention. The method includes objective measurements

11g and ll _of ocular aberrations of the left eye, respectively, and the right eye, calculations, denoted respectively 12 _g and 12 _d from the measured values of the aberrations of two criteria monocular performance characteristic functions respectively the imaging performance of each left and right eye, then the computation of the binocular visual performance criterion of the subject, by a summation function of the left and right monocular performance criteria. The summation function must be understood in the broad sense, that is to say any function of two parameters, strictly increasing with respect to each of the parameters. For example, the summation function is a simple addition, a quadratic summation, a summation in absolute value, and so on. As will be described in detail below, the monocular performance criterion can be to be spectral, for example a complex function defined from the optical transfer function of the eye obtained from said measured values of the aberrations, represented as a function of coordinates in a spatial frequency or angular frequency plane. It can also be spatial, for example a percussive response, represented as a function of spatial or angular coordinates. Advantageously, according to the invention, for at least one of the monocular performance criteria, the characteristic function of the imaging performance of the eye is recalibrated by application of a lateral shift. By lateral shift is meant, in the case of a spatial-type monocular criterion, a lateral spatial shift, that is to say the application in the plane of spatial or angular coordinates of a translation. For a monocular criterion of the spectral type, the lateral offset consists of adding a phase shift to the phase of said criterion.

Thus, thanks to the step of objective measurements of ocular aberrations of each eye and the particular treatment carried out from these measurements, the method according to the invention makes it possible, contrary to the methods described hitherto, an objective determination of performance criteria. visual binocular, that is to say in normal situations where both eyes contribute to vision, the binocular performance criterion being determined without the intervention of the patient and the resulting limitations. In particular, the invention applies to the determination of visual performance criteria of the binocular contrast sensitivity and binocular acuity type, as well as to the simulation of the retinal images perceived in binocular vision, as detailed below.

The objective determination of the aberrations of each eye is advantageously performed by measuring the aberrations by means of an objective aberrometer. A Objective aberrometer is an instrument that requires no response from the patient; aberrations are measured by projecting light into the patient's eye and measuring the light signal reflected through the eye by the retina by fully objective means. Several types of Aberrometers objectives have been developed, using different techniques: Shack-Hartmann (or Hartmann-Shack) deflectometric Moiré, ABERROMETRY Tscherning ^{'refractometer} laser scanning, dynamic retinoscopy, phase contrast, etc. These objective aberrometry techniques have the advantage of measuring all or a large majority of the monochromatic optical aberrations of the eye, that is to say both weak order aberrations such as defocusing (spherical defect). refracted wave) and astigmatism (cylindrical defect) and higher order aberrations such as coma, spherical aberration and other optical defects. These data make it possible to quantify non-uniform, asymmetrical, sometimes very irregular refractive errors that can affect the quality of vision. The patent application FR 0111112 describes a method for producing a compact objective aberrometer, adapted for clinical use, capable of measuring the aberrations experienced by the light through the whole of the ocular optics. This instrument also measures the aberrations resulting from the introduction of any optical correction (glasses, lenses, etc.) in front of or on the eye at the time of the examination. The values of the aberrations resulting from the measurements made on each of the two eyes can take different forms. This is for example a sampling of the ocular wavefront error in the pupil, a sampling of the slopes of the wavefront in the pupil, the coefficients of a decomposition of the error of the pupil. wavefront on a set predefined polynomial functions, for example Zernike polynomials up to a given order, etc. Preferably, the aberration data take the form of a Zernike polynomial decomposition of the ocular wavefront error.

According to the invention, for each of the two eyes, a monocular performance criterion is calculated, this criterion being a characteristic function of the imaging performance of each eye. As we have seen, the monocular criterion can be spectral or spatial.

According to a first example, the monocular performance criterion is a complex function, defined from the optical transfer function of the eye (or OTF according to the abbreviation of the English expression "Optical Transfer Function") obtained at from said measured values of the aberrations. The calculation of the OTF is for example carried out by Fourier transformation of the percussional response of the eye (or PSF according to the abbreviation of the English expression Point-Spread Function), itself obtained from said values. measured aberrations in a known manner.

From the two left and right monocular performance criteria, a binocular visual performance criterion characteristic of the performance achieved when both eyes operate simultaneously is deduced.

According to a first example of application of the method according to the invention, one is interested in the determination of the binocular contrast sensitivity. Advantageously, for the determination of the contrast sensitivity curve, each of said monocular performance criteria is obtained by the optical transfer function of each eye, weighted by a function of sensitivity to the neural contrast of the visual system, and adjusted by application of a phase shift equal to the opposite of the phase of said optical transfer function. The contrast sensitivity is then deduced from the left and right monocular criteria, for example by a quadratic summation of the two criteria.

Thus, the function of binocular contrast sensitivity (or CSF, abbreviation of the English expression "Contrast Sensitivity Function") is expressed as a function of the frequency coordinates f ± f _j , by the formula:

C $ F {ij) = NTF (fιj) x4θTFR (fιj) exύ-jPTFR (fιj)) ^ MθTFP

Where OTFPd (fi, jj) and OTFP _s (fι, β) represent the complex optical transfer functions of right and left eyes respectively, PTFPd {fi, fj) and PTFP _s {fi, fj) represent the respective phases of OTFPd ( fi, jj) and OTFP _g (fi, jj), and

ΗTF {fi, fj) represents the neural contrast sensitivity function of the visual system. The symbol "exp" represents the complex exponential function and j the complex number whose square is worth -1. Typical NTF (fi, jj) values can be obtained from several published studies (see, for example, GJ Barten, Contrast sensitivity of the human eye and its effects on image quality, 1999, SPIE, Bellingham, Washington, USA). The CSF (fi, jf) sensitivity, by its two-dimensional nature, can be reduced to a CSF (f) one-dimensional shape by extracting a profile according to a particular meridian of the spatial frequency plane or by computation. of the average profile on a set of meridians.

FIGS. 2A to 2C show, according to examples, the binocular contrast sensitivity curves of a subject obtained by means of the method previously described. The curves, respectively denoted 21d, 21g, 21b represent the contrast sensitivity calculated according to the horizontal meridian respectively for the right eye, the left eye and in binocular vision. These curves correspond to the case in which the subject sees patterns of sinusoidal contrast with lines oriented in the vertical direction. They are obtained by performing a horizontal section of the computed two-dimensional contrast sensitivity function. Thus on the abscissa is indicated the spatial frequency of the test pattern in cycles per degree. On the ordinate is represented the threshold of sensitivity, that is to say the inverse of the value of the lowest detectable contrast at the frequency considered.

It is possible from the contrast sensitivity curves of a subject, to determine the binocular visual acuity of the subject, the sharpness value can be deduced from the binocular contrast sensitivity curve.

For this, the cutoff frequency is determined, that is to say the highest spatial frequency value for which the sensitivity remains greater than or equal to 1

(ie for which the detectable contrast limit value remains lower than or equal to 1, ie 100% contrast). In FIGS. 2A to 2C, the cut-off frequencies are denoted fd _/ f _g , f _t , respectively. Visual acuity is then calculated either as a multiple of the cutoff frequency or as a function of the cutoff frequency. this function being determined by a statistical analysis of the relationships between the cutoff frequency and the subjective visual acuity.

According to one variant, the binocular visual acuity of the subject can be determined without going through the binocular contrast sensitivity calculation. According to this variant, the monocular performance criterion of each eye is the optical transfer function of the eye, recaled by applying a phase shift equal to the opposite of the phase of said optical transfer function. The binocular acuity is then obtained by determining a cutoff spatial frequency on the curve resulting from The summation function of the two left and right monocular visual performance criteria.

We now describe how the method according to the invention can be applied to the simulation of a retinal image perceived by a subject in binocular vision.

According to a first variant, each of said monocular criteria is the complex function resulting from the product of the optical transfer function of the eye and the spatial frequency spectrum of the object whose vision is to be simulated. Advantageously, for at least one of the monocular performance criteria, said complex function is recalibrated by application of a phase changeover term. This phase shift corresponds to a translation of the retinal image in its plane. It translates the adjustment of the viewing angle of each eye that is driven by the binocular fusion mechanism, a mechanism implemented by visual system when both eyes look at the same visual scene. Fusion makes it possible to superimpose the two images at the level of the visual cortex. I / binocular retinal image is then obtained for example by a Fourier transform of the result of the application of the summation function to the monocular performance criteria of each of the eyes. In the case of binocular imaging simulation, the summation function can be a simple addition.

Thus for the right eye, for example, the right monocular criterion corresponds to the spectrum of the retinal image calculated for the right eye:

This spectrum of the retinal image is obtained by performing the product of the OFS spectrum (fi, jf) of spatial frequencies of the object viewed by the optical transfer function of the corresponding eye. The OFS spectrum (β, jf) is

For example obtained by Fourier transformation of the luminance distribution of the object. So, for the right eye, the calculation is done by the formula:

IFS _d (fiJ)) = OFS (fij) χOTFR (fi, fj)

The spatial frequency spectra IFSd (fi, β) and IFSg (fi, fi) of the retinal images formed by the right and left eyes respectively are calculated.

The term of phase shift recommended is the adjustment of the angle of sight of each eye implemented by the visual system to promote a merged perception of the two images. To calculate it, we must estimate the effective slopes (sxd, syd) and (sxg, syg) of the phase variations of the spectrum IFSd {β, βj) and IFS _g {β, β)) with respect to the coordinates (fi, fj). This is a product-weighted average calculation between the spectrum modulus and the neural contrast sensitivity function.

For example, for the right eye, the local phase tilt horizontally, either for the right eye: phasejIFS jfiM ^d) fi where the symbol "phase" is the function that returns the phase of a complex number. We deduce a weighted average sxd of the local phase shift according to the horizontal: phase {lFS ^d {fi, j ^j ))) _{x abs} ( _IFSd (fi, j _j )) xNTF (fij)

Sxd = ~

(Abs {lfsd {ij)) xNTF {ij))

where the square brackets represent the averaging operation.

The same calculation is made for the vertical direction of the right eye (syd). The term of phase shift is then applied to the monocular criterion of the right eye by multiplying this criterion by: exç {-jx (sxdχfi-sydχjj))

The same operation is performed for the left eye. The term phase shift is therefore for a given spatial frequency, the opposite of the averaged value of the phase of each of the monocular performance criteria, weighted by the product of a neural contrast sensitivity function of the visual system with the module of said monocular criterion and with the inverse of said spatial frequency.

To obtain the spatial frequency spectrum of the binocular image, a simple summation of the left and right monocular criteria is carried out:

The binocular image is then computed by Fourier transform of the frequency spectrum of the binocular image.

By way of example, FIGS. 3A to 3C show the simulated images of a letter "E" calculated by the applicant on a patient, respectively for the right eye, the left eye and in binocular vision (curves 31a, 31b). _g ,

31 _b ) •

According to a variant, for the simulation of a retinal image perceived by binocular vision by a subject, the monocular criteria can also be calculated by the complex function obtained by the product of the optical transfer function of the eye and the frequency spectrum space of the object, multiplied by the module of the product. The remainder of the calculation is unchanged from that previously described. Thus in this variant for the right eye, the monocular performance criterion is, taking again the notations defined previously:

IFSV _d (jJ)) = IFS _d {βJ)) χ \ lFS, {βJ))

The binocular spectrum is obtained by the simple summation of the recalculated monocular criteria:

According to a variant, the method according to the invention also makes it possible to give binocular performance criteria according to the viewing distance of a patient. This variant is illustrated by the diagram of FIG. 4. This variant is particularly interesting because, under certain conditions, such as presbyopia or the wearing of intraocular implants as a result of cataract surgery, visual performances are often optimal. for a particular viewing distance and degraded for other distances. It is therefore important to be able to diagnose visual performance for any distance of vision useful in everyday life.

According to this variant, a set of measurements of the eye aberrations is made for each eye for different viewing distances (41 _g , 41 _d ). The method includes selecting for each eye one of the measurements as a function of the given viewing distance and correcting at least one of said selected measurements based on the accommodation path of each eye. The accommodation path is the interval of. defocusing of the eye limited by the lower and upper values of the spherical defocuses deduced from the set of ocular aberration measurements. If the given viewing distance is within the accommodation course, the correction preferably consists in canceling the spherical defocus of the selected measure, so as to take into account the perfect accommodation of the eye at a distance. given vision. Thus the correction makes it possible to restore the continuity of the adjustment of the eye as a function of the distance, from measurements made for a discrete set of viewing distances. If the distance of vision is outside the accommodation course, the correction will preferably match the spherical defocus of the selected measure as one of the limit values of the accommodation path. The monocular performance criterion characteristic of the retinal imaging of each eye is then calculated from said aberration-corrected value (42 _g , 42 d, according to the same methods as those previously described, as previously, the binocular performance criterion at the The patient's chosen viewing distance is then deduced from the determined monocular performance criteria at said viewing distance by a summation function.

To determine the monocular performance criterion, it is also possible to perform a calculation of the aberrations at the chosen viewing distance, by interpolation from the set of measurements. The monocular performance criterion characteristic of the retinal imaging of each eye is then calculated from the interpolated value of the aberrations. FIGS. 5A and 5B illustrate, by simplified diagrams, the production of a device for implementing the method according to the invention as previously described.

In general, the device for implementing the method of objective determination of binocular visual performance criteria comprises an objective measurement system SM ocular aberrations of an eye 0, a control and processing unit UPT. The driving and processing unit notably makes it possible to calculate from the measured values of the aberrations of each of the two monocular performance criteria characteristic of the retinal imaging of each eye and the calculation of the binocular visual performance criterion of the subject, by a summation of said left and right monocular performance criteria. The measurement system SM (not shown in detail in FIGS. 5A and 5B) comprises, for example and in a known manner a lighting device with a light source forming a light beam on the retina, a device for analyzing the surface of the retro light wave reflected by the retina and coming from the eye, a device visualizing the anterior surface of the eye to assist in clinician positioning of the instrument. The wavefront analysis system is for example Shack-Hartmann type as described above. According to the example of FIG. 5A, CSA means for controlling the distance of vision of the patient are furthermore provided in order to implement the method of predicting binocular visual performances as a function of the viewing distance. In the example of FIG. 5A, the CSA control means are made by driving a visual target C with respect to the optical system SO thanks to a translation platform T. Of course, other variants are possible for the means CSA control. For example, a fixed target may be associated with a translating system movable in translation, or the target may be fixed, and the optical system SO with variable focus electrically controlled.

FIG. 5B illustrates a variant according to which the measuring channel is integral with the translation movements of the target.

Well, of course, these examples are not exhaustive and many device variants are possible for the implementation of the method ^1A invention.

Claims

KESVENDICATIONS

1- Method for objective determination of a binocular visual performance criterion of a human or animal subject, characterized in that it comprises:

- the objective measurement of the ocular aberrations of each eye (H ₉ , Hd) _r

calculating from the measured values of the aberrations of a monocular performance criterion for each of the left and right eyes (12 _g , 12 _d ) _/ said criteria being characteristic functions of the imaging performance respectively of each left eye and right, calculating (13) the binocular visual performance criterion of the subject, by a summation function of said left and right monocular performance criteria.

2. The method of claim 1, wherein for at least one of said monocular performance criteria, said characteristic function of the imaging performance of the eye is recalibrated by application of a lateral shift.

3- Method according to one of claims 1 or 2, wherein said monocular performance criterion is a complex function, defined from the optical transfer function of the eye obtained from said measured values of the aberrations.

4. The method of claim 3, wherein the optical transfer function is calculated from the percussion response of the eye obtained from the measured values of the aberrations.

5. Method according to one of claims 3 or 4 for determining the binocular contrast sensitivity curve of the subject, wherein each of said monocular performance criteria is obtained by the optical transfer function of each eye, weighted by a function of sensitivity to the neural contrast of the visual system, and adjusted by applying a phase shift equal to the opposite of the phase of said optical transfer function. 6. The method of claim 5, further allowing the determination of the binocular visual acuity of the subject, said acuity value being calculated from the cutoff frequency, deduced from the binocular contrast sensitivity curve. 7- Method according to 1. ' one of claims 3 or 4 for determining the binocular visual acuity of the subject, wherein the binocular sharpness is obtained by determining a cutoff spatial frequency on the curve resulting from the summation function of the two visual performance criteria. monoculars left and right.

8- Method according to one of the preceding claims, wherein the summation function is a quadratic summation. 9- Method according to one of claims 3 or 4 for the simulation of a retinal image perceived in binocular vision by a subject, wherein for each of said monocular performance criteria, said complex function is the product of the optical transfer function of the eye and the spatial frequency spectrum of the object.

10- Method according to one of claims 3 or 4 for the simulation of a retinal image perceived in binocular vision by a subject, wherein for each of said monocular performance criteria, said complex function is obtained by the product of the function optical transfer of the eye and the spatial frequency spectrum of the object, multiplied by the module of said product. 11- Method according to one of claims 9 or 10, wherein for at least one of said criteria of Rerforman.ce monocular, said complex function is recaled by applying a term of phase shift.

12- Method according to claim. 11, wherein said phase swinging term is for a given spatial frequency, the opposite of the averaged value of the phase of each of the monocular performance criteria, weighted by the product of a system neural contrast sensitivity function. visual with the module of said monocular criterion and with the inverse of said spatial frequency.

13- Method according to one of claims 1 or 2 for the simulation of a retinal image perceived in binocular vision by a subject, wherein for each of said monocular performance criteria, said characteristic function of the imaging performance of the eye is a monocular image calculated in the plane of the retina.

14- The method of claim 13, wherein the monocular image is calculated in the plane of the retina by convolution of the percussion response of the eye with the luminance spatial distribution of the object.

15- Method according to one of claims 13 or 14, wherein for at least one of said monocular performance criteria, said monocular image is recaled by applying a translation of said image along a given vector.

16- Method according to one of claims 1 or 2 for determining the binocular visual acuity of the subject, wherein for each of said monocular performance criteria, said characteristic function of the imaging performance of the eye is the response percussion of the eye calculated in the plane of the retina, said percussion function being recaled for at least one of the two criteria by application of a translation along a given vector, the binocular acuity value resulting from a calculation of a characteristic of ^r spatial extent of the summation function of said monocular criteria. The method of claim 16, wherein said summing function is an addition.

18- Method for determining a binocular visual performance criterion according to one of the preceding claims, for a given viewing distance of the subject, in which a set of measurements of the eye aberrations is made for each eye for different viewing distances ( 41 _g , 41a), the method further comprising selecting (43) for each eye of one of said measurements as a function of the given viewing distance, correcting at least one of said selected measurements as a function of the viewing distance. accomodation of each eye, the criterion of monocular performance characteristic of the retinal imaging of each eye being calculated from said corrected value of the aberrations (42 _g , 42a)

19- A method of determining a binocular visual performance criterion according to one of claims 1 to 17, for a given viewing distance of the subject, wherein a set of measurements of ocular aberrations is made for each eye for different distances of vision, the method further comprising for each eye a calculation of the aberrations at said interpolated vision distance from said set of measurements, the characteristic monocular performance criterion of the retinal imaging of each eye being calculated from said corrected value aberrations.

20- Apparatus for implementing the method of objective determination of a binocular visual performance criterion of a human or animal subject according to one of the preceding claims, characterized in that includes an objective measurement system (SM) eye aberrations of an eye, a treatment unit

(UPT) allowing in particular the calculation, from the measured values of the aberrations, of each of the monocular performance criteria characteristic of the retinal imaging respectively of each of the two eyes, and the calculation of the binocular visual performance criterion of the subject, by a summation function of left and right monocular performance criteria. 21. The device according to claim 20, wherein the objective aberration measurement system comprises a Shack-Hartmann type wave surface analyzer.

22- Device according to one of claims 20 or 21, further comprising means (CSA) for controlling the distance of vision of the patient.