Device and method for analyzing vision binocularity

Abstract

The present invention provides a device for examining the binocular vision and methods for analyzing vision binocularity utilizing the device. Generally the device has at least a laser channel configured to emit laser beams for ray tracing, a beam divider, right-eye and left-eye measurement channels, a processing unit and an electro-mechanical. The methods compare processed data from the right-eye and left-eye measuring channels to calculate correlation coefficients for near and far vision, to evaluate mirror asymmetry of wave front errors of the eyes, by considering potential involvement of anisocoria due to a planned surgery, and utilizing a neurological summing potential by a binocularity vision index.

Description

[0001] DEVICE AND METHOD FOR ANALYZING VISION BINOCULARITY

[0002] This international patent application claims benefit of priority under 35 U.S.C. §119(e) of provisional patent application U.S. Serial No. 63 / 554,548, filed February 16, 2024, the entirety of which is hereby incorporated in its entirety.

[0003] BACKGROUND OF THE INVENTION

[0004] Field of the Invention

[0005] The present invention relates generally to the fields of ophthalmic instruments that are used to examine human vision. More specifically, the present invention relates to ophthalmic examination instruments that measure the parameters of vision synchronously in both eyes and evaluate the degree of their synergic functioning.

[0006] Description of the Related Art

[0007] Brain synergic processing of visual information from fellow eyes results not only in the possibility of 3D orientation due to visual stereopsis but also in higher visual capabilities. It was demonstrated experimentally by F. Cambell and D. Green from the University of Cambridge in their communication “Monocular versus binocular vision acuity” (Nature, 1965, Vol. 208, pp. 191-193) that binocularity provides a gain in visual acuity in the range between 1 (no gain) to 2 (maximal gain) with mean value equal to the square root of 2.

[0008] On the other side, since the binocular summation is influenced by interocular asymmetry, it is important to examine the binocularity function to prognose the quality of vision before being subjected to the surgical techniques that will involve changes in binocular vision and to be informed concerning the limitations in terms of binocular visual performance after surgery (Castro, et al. Binocular summation and visual function with induced anisocoria and monovision. Biomedical Optics Express, 2016, Vol. 7, pp. 4280-4292). Mechanisms of binocularity were analyzed in depth in the 3- volume monograph “Perceiving in Depth” edited by I. P. Howard (Oxford University Press, 2012).

[0009] The early description of the binocular Shack-Hartmann sensor for the human eye was provided by Hampson, et al. in Journal of Modern Optics, 2008, Vol. 55, pp. 703-716. It contains two channels with a common laser and a common Shack- Hartmann sensor. The target is observed in the open-view mode via two hot mirrors placed at 75 mm in front of the eyes. This arrangement enables the patient to view the target in free space close to natural viewing conditions. The centroid of each Shack- Hartmann spot is then evaluated by means of suppressing the speckle structure of small laser spots. The same configuration of a binocular configuration was used for studying the ocular aberration dynamics (Chin, et al. Binocular correlation of ocular aberration dynamics. Optics Express, 2008, Vol. 16, pp. 14734-14745).

[0010] A similar approach was used to configure the binocular system for vision testing, consisting of two identical monocular channels. (Sabesan, et al., Binocular visual performance and summation after correcting higher order aberrations. Biomedical Optics Express, 2012, Vol. 3, pp. 3476-3489). Each monocular system consists of a Shack-Hartmann wavefront sensor and a visual stimulus display. Compensating for higher-order aberrations with adaptive optics wave front correction the authors evaluated the visual performance provided by binocular summation of the corrected vision.

[0011] A method for the binocular measurement and control of eye aberrations which simultaneously provides visual stimulation was described in U.S. Patent Publication No. 2012 / 0038884. The instrument consists of a laser and means for splitting its beam between the right and the left eyes, a single Shack-Hartmann aberration sensor and active optic means for correcting aberrations in each eye separately.

[0012] A succession of similar designs each with two monocular Shack-Hartmann sensors on a common platform have been disclosed including in the Chinese Publication No. CN 105943300 (M. Jiang, et al. Binocular wavefront aberration visual optical analysis system).

[0013] None of the described solutions outputs an evaluation of the synergic action of two separate vision estimates. Moreover, Shack-Hartmann sensors issuing multiple small-format matrices of measuring signals cannot provide high-resolution data being distorted thereto by the speckle structure of the coherent laser light. Destroying the speckles does not help in higher spatial resolution. Thus, there is a need in the art for other solutions for avoiding low-quality signals for evaluation of the local quality of both ocular optical systems that enable the evaluation of the synergic action of the right and left components of the human visual system. The present invention fulfills this long-standing need and desire in the art. SUMMARY OF THE INVENTION

[0014] Provided herein is a device for obtaining the wave front data from the synchronized ray tracing measurements of both eyes and comparing their different aspects to get the estimate of synergy provided by the binocularity.

[0015] The device for examining the binocular vision contains a laser channel emitting the laser beams for ray tracing making this procedure consecutive in time and in parallel to the optical axis. The cross-sections of the beam traces create beam patterns filling completely or partially the apertures of each eye separately. The beam patterns, divided into two paths by a beam divider, are delivered to the right eye and to the left eye transiting the right-eye measurement channel and the left-eye measurement channel correspondingly. Each of the measurement channels, oriented to detect the light coming back from the right eye and from the left eye, contains a positioning block, an optometric block, and a photodetector block configured to measure the position of the laser beam projection on the retina. The device also contains a processing unit and a display, where the processing unit is electrically connected to the laser channel and to both measurement channels. Between the processing unit and the display, a disparity calculation unit is set up and is configured to operate with the processed data from the right-eye measuring channel and from the left-eye measuring channel. The processed data includes the signal levels, the wave front aberrations and their derivatives, including the modulation transfer functions and the point spread functions. The device contains an electro-mechanical unit aligning the distance between the right-eye measurement channel and the left-eye measurement channel corresponding to the inter-ocular distance of a patient,

[0016] The laser channel contains a single two-coordinate acousto-opticalal deflector connected to a driver. The driver is controlled by a frequency synthesizer, connected to and controlled by the processing unit, where the frequency synthesizer generates frequencies tilting the laser beams to produce two spatially separated beam patterns.

[0017] The first beam pattern is designated for probing the right eye according to the time schedule of the right eye measurement after having propagated through the righteye measurement channel. The second beam pattern is designated for probing the left eye according to the time schedule of the left eye measurement after having propagated through the left-eye measurement channel. The beam divider is made of a two-mirror roof with its right side directing the right-eye laser beam pattern to the right-eye measuring channel, and with its left side directing the left-eye laser beam pattern to the left-eye measuring channel.

[0018] The proposed method of vision binocularity analysis comprises comparing the processed data from the right-eye measuring channel and from the left-eye measuring channel, in particular correlation coefficients calculated for the near and far vision of each eye between the wave front errors for different modes of accommodation - in an open-field mode and with separate targets of each measuring channel.

[0019] Another method of analysis uses the mirror asymmetry of the wave front errors of the right eye and of the left eye being evaluated by the module and the angle of the comma members of Zernike series.

[0020] Yet another method of analysis comprises a potential involvement of anisocoria due to planned surgery, the anisocoria being simulated by the control of the beam pattern generated by the synthesized frequencies in the laser channel.

[0021] Still another method of analysis involves the neurological summing potential described by a binocularity vision index, ranging from zero to a highest value proportionally to the amount of difference in the processed data between the dominant eye and the fellow eye.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] So that the above-recited features of the invention are to be understood in detail, more particular descriptions of the invention briefly summarized above are illustrated in the appended drawings. These drawings form a part of the specification. However, that the appended drawings illustrate preferred embodiments of the invention, they are not to be considered limiting in their scope.

[0024] FIG. 1 is the structural schematic of the device for examining the binocular vision. Its optical part consists of the laser channel 1 and of the right-eye measuring channel 2R and the left-eye measuring channel 2L. The device is under the control of the processing unit 4, whose output data are used for the analysis of binocularity by the disparity calculation unit 5.

[0025] FIG. 2 illustrates the structure of the laser channel 1. The right-eye set of laser beams 34 and the left-eye set of laser beams 35 are formed by the same acousto- opticalal deflector 25. As a result, after the collimating lens 27, two separate laser beam patterns are created: 36 for the right eye, and 37 for the left eye. Their size and configuration can be controlled for each eye independently.

[0026] FIG. 3 illustrates the laser beam patterns 36 and 37 as projected through the eye apertures 38 and 39.

[0027] FIG. 4 illustrates the [Fx * Fy] matrix of frequencies Fxand Fy to control the acousto-opticalal deflector 25, shown in FIG. 2, to get two laser beam patterns 36 and 37 illustrated in FIG. 3. For example, the axial direction in the right-eye beam pattern is generated by Fx=56 MHz and Fy=60 MHz, the axial direction in the left-eye beam pattern - by Fx=64 MHz and Fy=60 MHz.

[0028] FIG. 5 is a time diagram of the Fx and Fy synthesized frequencies producing a pattern of 12 points equidistantly positioned along a circle of 4 mm in diameter. In each position, the eye is illuminated for 1 ms. In the first 12 ms, the right pattern is generated. In the next 12 ms, the left pattern is generated.

[0029] FIG. 6 demonstrates another sequence of beam positioning for creating the same patterns. Switching the points in the fellow patterns is made point-by-point, not like in FIG. 5, which is pattern-by-pattern.

[0030] DETAILED DESCRIPTION OF THE INVENTION

[0031] As used herein, the articles “a” and “an” when used in conjunction with the term “comprising” in the claims and / or the specification, may refer to “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one”. Some embodiments of the invention may consist of or consist essentially of one or more elements, components, method steps, and / or methods of the invention.

[0032] As used herein, the term “or” in the claims refers to “and / or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and / or”

[0033] As used herein, the terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included.

[0034] As used herein, the terms “consists of’ and “consisting of’ are used in the exclusive, closed sense, meaning that additional elements may not be included. As used herein, the term “includes” or “including” refers to “including, but not limited to”. The terms “includes, “including” and “including, but not limited to” are used interchangeably

[0035] As used herein, the term “about” to a numeric value, including, for example, whole numbers, fractions, and percentages, whether or not explicitly indicated. The term “about” generally refers to a range of numerical values (e.g., ± 5-10% of the recited value) that one of ordinary skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In some instances, the term “about” may include numerical values that are rounded to the nearest significant figure. In a non-limiting example a value of about 10 ps encompasses 9 ps to 11 ps.

[0036] In one embodiment of the present invention there is provided a device for examining the binocular vision, comprising a laser channel configured to emit laser beams for ray tracing consecutively in time in parallel to the optical axis; cross-sections of the beam traces creating a beam pattern covering the aperture of the eye; a beam divider; a right-eye measurement channel and a left-eye measurement channel; optically connected to the laser channel via said beam divider; each containing a photosensitive matrix optically conjugated with an entrance aperture of the eye, a visually observable target with the ability to be conjugated with the retina; and a position sensing photodetector configured to measure a position of a laser beam projected onto a retina of the eye; a processing unit electrically connected to the laser channel and to the right-eye measurement channel and to the left-eye measurement channels, said processing unit having a display at its output; and an electromechanical unit configured to align the distance between the right-eye measurement channel and the left-eye measurement channel to correspond to the inter-ocular distance of a patient.

[0037] Further to this embodiment the method comprises a disparity calculation unit disposed between the processing unit and the display, said disparity calculation unit configured to operate with the processed data from the right-eye measuring channel and from the left-eye measuring channel. In this further embodiment the processed data may comprise signal levels, wave front aberrations and derivatives thereof, where the derivatives may comprise modulation transfer functions and the point spread functions. In both embodiments the laser channel may contain a single two-coordinate acousto-opticalal deflector connected to a driver operably controlled by a frequency synthesizer that is connected to and operably controlled by the processing unit.

[0038] Also in both embodiments the laser channel may contain a single two- coordinate acousto-optical deflector connected to a driver operably controlled by a frequency synthesizer that is connected to and operably controlled by the processing unit. Particularly, the frequency synthesizer is configured to generate frequencies that tilt the laser beams to produce two spatially separated beam patterns. More particularly, one of the spatially separated beam patterns is configured to probe the right eye according to a time schedule for a right eye measurement after having propagated through the right-eye measurement channel and the other of the spatially separated beam patterns is configured to probe the left eye according to the time schedule of the left eye measurement after having propagated through the left-eye measurement channel.

[0039] In addition the beam divider may comprise a two-mirror roof with a right side to direct the right-eye laser beam pattern to the right-eye measuring channel, and with a left side to direct the left-eye laser beam pattern to the left-eye measuring channel.

[0040] In yet another embodiment of the present invention there is provided a method for analyzing vision binocularity, comprising comparing processed data from the righteye measuring channel and from the left-eye measuring channel of the device, as described supra, by calculating correlation coefficients for the near and far vision of each eye between the wave front errors measured with eyes accommodated relatively using a common target in an open-field mode or separate targets of each measuring channel. In this embodiment the difference of the correlation coefficients for the right eye and for the left eye may comprise the measure of aberration disparity of the fellow eyes.

[0041] In yet another embodiment of the present invention there is provided a method for analyzing vision binocularity, comprising comparing processed data from the righteye measuring channel and from the left-eye measuring channel of the device, as described supra, by evaluating mirror asymmetry of wave front errors of the right eye and of the left eye by a module and an angle of the coma member of Zernike series. In this embodiment the mirror asymmetry of the wave front errors may comprise another measure of aberration disparity of fellow eyes. In yet another embodiment of the present invention there is provided a method for analyzing vision binocularity, comprising comparing processed data from the righteye measuring channel and from the left-eye measuring channel of the device, as described supra, wherein analysis comprises a potential involvement of anisocoria due to a planned surgery, said anisocoria simulated by controlling the beam pattern in a proportion of suggested results of the planned surgery. In this embodiment the beam pattern may be generated by frequencies synthesized in the laser channel.

[0042] In yet another embodiment of the present invention there is provided a method for analyzing vision binocularity, comprising comparing processed data from the righteye measuring channel and from the left-eye measuring channel of the device, as described supra, by describing a neurological summing potential by a binocularity vision index, wherein a zero value of the binocularity vision index is ascribed when the processed data corresponds to one of the eyes being blind, and the highest value of the binocularity vision index is ascribed when both eyes have equal values of the processed data, wherein intermediate values of said binocularity vision index are proportional to an amount of difference in the processed data between a dominant eye and a fellow eye.

[0043] The present embodiments are best described by reference to the figures, but are not meant to limit the present invention in any fashion.

[0044] The structure of the proposed device for examining the binocular vision is illustrated by FIG. 1. The device contains a laser channel 1, two eye measurement channels 2R and 2i_, where 2R is a right-eye measurement channel, and 2L is a lefteye measurement channel 2i_, a laser beam divider 3, a processing unit 4, a disparity calculation unit 5, a display 6, and an electro-mechanical unit 7. The channels 2R and 2L are identical, their elements being denoted by the same numbers but with the subscripts, where the subscript R means that the element relates to the right-eye measurement channel 2R, and the element with the subscript L relates to the left-eye measurement channel 2L. The eyes are denoted by 8R for the right eye and 8L for the left eye

[0045] Each of two eye-measuring channels 2R and 2L contains elements through which the laser beams are propagated, these elements are: a mirror 9R and 9L, a first beam splitter 10R and 10L, a fluidic lens 11R and 11 L, a first lens 12R and 12i_, and a second beam splitter 13R and 13i_. On the path backward from the eye, the second beam splitter splits the optical axis turning it to the video camera consisting of an objective lens 14R and 14i_ and a photosensitive matrix 15R and 15i_. Both photosensitive matrices are connected to the processing unit 4. Another part of the light from the eye, having passed the second beam splitter, continues its path through the first lens, the fluidic lens 11 , the first beam splitter, a second lens 18R and 18L, and a third beam splitter 17R and 17i_ to a position sensing photodetector 19R and 19i_. A target 16R and 16L is projected into the eye through the third beam splitter, the second lens 18R and 18L, the first beam splitter 1 OR and 10L, the fluidic lens 11R and 11 L, the first lens 12R and 12i_, and the second beam splitter 13R and 13i_.

[0046] The fast electrically tunable lenses of the Optotune EL-10-33 series can be used as fluidic lenses 11R and 11i_. There are several modifications of them (EL-12- 33, EL-16-40, etc.) with light apertures up to 16 mm and with the range of adjustable optical power from -10 to +10 diopters, or wider. The term “position sensing photodetector” (19R and 19L) is often used in a shorter version - “position sensitive detector” (PSD). For the purposes of this invention, any of two known classes of position sensitive detectors can be used. One of them has an isotropic sensor surface that supplies continuous position data, such as Hamamatsu S3935 (one-dimensional data with sensitive area 1 x12 mm) or Hananatsu S5991-01 (two-dimensional data with sensitive area 9x9 mm). Another class of position sensitive detectors has discrete sensors with one-dimensional structure (linear arrays) or fast (1602 frames per second) two-dimensional raster-like structure (Hamamatsu profile sensor S15396-512 with a built-in center-of-gravity calculator). One-dimensional PSDs position sensitive detectors additional path splitting to measure X and Y coordinates separately. The principles of this invention do not depend on the type of position sensitive detector and may be implemented with any position sensitive detector.

[0047] The fluidic lenses 11R and 11 L, the position sensing photodetectors 19R and 19L, the right-eye target 16R and the left-eye target 16L, are electrically connected to the processing unit 4 via their individual lines in a bus 20.

[0048] The device is designed to provide an open-field (open-view) measurement. The optical parts of the right-eye and the left-eye channels 2R and 2L are shielded by shells 21 R and 21 L having first windows 22R and 22i_ for light to access the right and the left eyes Sp and 8L, and second windows 23R and 23L to orient the patient’s sight on the objects outside the device.

[0049] A laser channel 1 comprises the elements positioned one after another (FIG. 2): a laser 24, an acousto-optical deflector (AOD) 25, a telescope 26, and a collimating lens 27. The acousto-optical deflector (AOD) 25 is a two-coordinate device deflecting the laser beam in orthogonal, X and Y directions. The telescope 26 consists of a pair of lenses 28 and 29. The acousto-optical deflector has a single center of scanning C in X and Y directions. The other two components of the laser channel 1 are: an X- driver 30 and a Y-driver 31 that are electrically connected through their outputs to the acousto-opticalal deflector 25. The input of the X-driver 30 is connected to the output of an X-frequency synthesizer 32, and the input of the Y-driver 31 is connected to the output of a Y-frequency synthesizer 33. The laser 24, the X-frequency synthesizer 32, and the Y-frequency synthesizer 33 are connected to the processing unit 4 (see FIG. 1 ) via the individual wires of the bus 20.

[0050] The front focus of the collimating lens 27 coincides with the relayed center of scanning C at the exit of the telescope 26. This results in two conical sets of laser beams (the right-eye set 34 and the left-eye set 35) with their apexes in the center of scanning C'. After the collimating lens 27, two parallel bunches of laser beams are formed creating two beam patterns: the right-eye beam pattern 36 and the left-eye beam pattern 37. The term “a bunch of laser beams” in this description means a space within which the laser beams can propagate not simultaneously, but in any time sequence. Similarly, the term “a pattern of laser beams” means that the pattern is a cross-section of “the bunch of laser beams”.

[0051] Examples of the patterns of laser beams are illustrated in FIG. 3, where the right-eye beam pattern 36 and the left-eye bean pattern 37 are enclosed within the dotted circles. The right-eye beam pattern 36 fills the right-eye aperture 38, and the left-eye beam pattern 37 fills the left-eye aperture 39. The filling of the eye aperture may be full or partial, depending on the size of the zone within the eye aperture from which the information should be obtained. In this example, the orientation of the X coordinate of the right and of the left eyes is outward in the horizontal direction.

[0052] The beam patterns 36 and 37, generated by the laser unit 1 , are directed into the eyes 8R and 8L transiting through the right-eye measurement channel 2R and the left-eye measurement channel 2L (FIG. 1 ). It is preferable to choose the laser wavelength in the infrared not only from patient-friendly considerations, but from the design arguments too - for such choice, one may use a spectrally selectable mirror 9R and 9L, usually known as a hot mirror, meaning that it functions as a mirror for the infrared, and as a transparent window for the visible wavelengths. It enables an opportunity to have an open-field mode of eye accommodation.

[0053] Before starting the patient eye examination and measurements, the interocular distance is adjusted using the electro-mechanical unit 7. The process of adjustment is controlled by the operator using the images of the eyes 8R and 8L on the display 6 formed by the photosensitive matrices 15R and 15L of the video camera. This procedure is accompanied by the subjective comments from the patient looking at the targets 16R and 16L or through the hot mirrors 9R and 9L, transparent in the visible. The next preparation step is accommodation alignment in accordance with the schedule of examination. During this process, the patient may adjust the eyes to get the target images in focus controlling the fluidic lenses 11 R and 11 L, the right eye and the left eye separately.

[0054] Measurements start from activation of the laser channel 1. Having received the command from the processing unit 4 through the bus 20, the laser 24 starts generating the laser beam directed into the acousto-opticalal deflector 25 (FIG. 2). While laser 24 is switched on, the processing unit 4 sends commands to the X- and / -frequency synthesizers 32 and 33. To conjugate source-load impedances, the X and Y drivers 30 and 31 are imbedded between the X- and / -frequency synthesizers 32 and 33 and the acousto-opticalal deflector 25. Deflection angles in X and / directions at the output of the deflector 25 are M* times magnified by the telescope 26, while the beam diameter is magnified (1 / / WX) times. Angular scanning at the output of the telescope 26 is converted in the lateral translation of the laser beams after the collimation lens 27. The order of angular scanning at the output of the telescope 26 is several angular degrees, the diameter of the laser beam at the output of the collimating lens 27 is several hundred micrometers.

[0055] FIG. 4 illustrates the correspondence of the frequencies Fx and Fy to the X and / coordinates in the right-eye beam pattern 36 and in the left-eye beam pattern 37. In this example, (0,0) coordinates in the right-eye beam pattern 36 correspond to the X and / frequencies Fx = 56 MHz and Fy = 60 MHz, while the (0,0) coordinates of the left-eye beam pattern 37 correspond to the Xand / frequencies Fx = 64 MHz and Fy = 60 MHz.

[0056] Although several frequencies may be generated simultaneously by each of the frequency synthesizers 32 and 33, the preferable mode of frequency synthesis for the purposes of this invention is only one frequency for the X direction, and only one frequency for the Y direction at a moment. The result of this mode is a single laser beam inside the beam pattern. The duration of keeping a certain position of the beam inside the beam pattern is of the order of a millisecond, the same is the duration of the control signal from the processing unit 4. Depending on the schedule of eye examination, the beam patterns may be created in any preferable sequence.

[0057] FIG. 5 illustrates an example of creating two patterns: the right-eye beam pattern 36 and the left-eye beam pattern 37, each of them consisting of 12 points equally distributed along a circle, 4 mm in diameter, for probing each eye in 12 points. The vertical axis denotes frequencies (in MHz) generated by the synthesizers: Fx by the synthesizer 32, and Fy by the synthesizer 33. The horizontal axis in the diagram of FIG. 5 denotes the time lapsed. The horizontal scale at the top of FIG. 5 shows the numbering of the pattern points: in the right-eye beam pattern (left part of the drawing) and in the left-eye beam pattern (right part of the drawing). Exposure of each eye in each point is 1 ms. Switching from one position to another takes about 10 ps. Synthesizer frequencies, the time of probing, and the beam patterns are given only as an example that does not restrict the invention, any other suitable parameters may be applied. In this example, the left-eye pattern 37 starts after the right-eye pattern 36 has been formed.

[0058] As an alternative, the beams from both patterns may be generated alternately. In the example illustrated in FIG. 6, exposures in the right-eye beam pattern and in the left-eye beam pattern are alternating. For example, the probing of the eye in the fifth point 5R of the right-eye beam pattern follows after the execution made in fifth point 5L of the left-eye beam pattern, and so on: 6L-6R, 7L- R, 8L-8R, etc. The frequency Fy is being kept by the / -frequency synthesizer for 2 ms, while the frequency Fx is being kept by the X-frequency synthesizer only for 1 ms. This is valid only if the points in the right-eye beam pattern and in the left-eye beam pattern follow each other in a certain order (symmetrical positions for the case of Fig. 6). Since the time of beam repositioning is about ten microseconds and it does not depend on how far the sequential points are from each other, both approaches are identical. Another beam positioning order may be applied not changing the teachings of this invention.

[0059] The commands from the processing unit 4 to the frequency synthesizers 32 and 33 are synchronized with the commands to the position sensing detectors 19R and 19L. An image of the light spot from the laser beam projection on the retina is formed by the optical system of the eye 8R and 8L and the objective lens 18R and 18L after relaying through the telescope lenses 12R and 12i_ and 11R and 111_. As described above, the fluidic lens 11R and 11 L is electrically controlled, at first from subjective impression of the patient in the pre-measurement phase. The initial subjectively established position of the fluidic lens may be adjusted after calculating the defocus component of the Zernike series. The principle of wave front conjugation teaches that the laser beams following into the eye through lenses 11R and 11 L and 12R and 12i_, being parallel at the entrance of the conjugation telescope, keep being parallel after having passed lenses 11R and 11 L. and 12R and 12i_ in the back direction from the eye. The principle of conjugation was described earlier (see UA Patent Nos. 104397 and 104398).

[0060] The coordinates of the laser beam in the entrance aperture of the eye (eye pupil), available as commands from the processing unit 4, and the coordinates of the projected laser spots on the retina, delivered to the processing unit 4 from the position sensing detectors 19 through the bus 20, are used for reconstruction of the wave front map (map of the wave front errors, or the aberration map) of each of the eyes, their principles being described elsewhere, e.g., in the article by V. Molebny et al. “Eye aberrations analysis with Zernike polynomials”. Proceedings of SPIE, Vol. 3246, 1998.

[0061] The analysis of vision binocularity is based on comparing the processed data from the right-eye measuring channel and from the left-eye measuring channel of the proposed device. In one of the options, the processed data are the wave front errors that may be graphically presented as the maps of wave front errors (known as wave front maps). The correlation coefficients are calculated between the wave front errors for the near and far vision of each eye measured with two different approaches of accommodation. In the first approach, both eyes are accommodated relatively using a common target in an open-field mode. The second approach uses separate targets available in each measuring channel. The switching between the approaches is provided by switching on / off the targets 16R and 16i_. For this purpose, the targets may be back illuminated by the light sources like light emitting diodes or being the micro displays. Closing and opening the second windows 23R and 23L may be additionally used. The difference of correlation coefficients for the right eye and for the left eye are the measure of aberration disparity of the fellow eyes.

[0062] Another way to analyze the vision binocularity is to evaluate the mirror asymmetry of the wave front errors of the right eye and of the left eye. This asymmetry is evaluated by the module and the angle of comma members of Zernike series. The more asymmetric the mirror asymmetry of the wave front errors is, the higher disparity of binocular vision is between the fellow eyes.

[0063] Still another way of analysis comprises a potential involvement of anisocoria that could apparently take place because of the planned surgery. The surgery-induced anisocoria may lead to significant disparity of the binocular vision. Its consequences are evaluated by simulation of varying right or left eye beam patterns 36 or 37 within the right eye aperture 38 or the left eye aperture 39 correspondingly. The control of the beam pattern in the left or in the right eye, depending on which of them is planned to be operated on, is implemented by the set of synthesized frequencies in the laser channel 1. The scaling of beam patterns is provided in the proportion of suggested results of the planned surgery.

[0064] It is well established that the level of synergy provided by the binocularity of vision depends on the neurological summing potential as described herein by a binocularity vision index. The zero value of the index is ascribed when the processed data correspond to one of the eyes being blind. The highest value of the index is established when both eyes have equal values of the processed data. The intermediate values are proportional to the amount of difference in the processed data between the dominant eye and the fellow eye. The processed data may comprise, but is not limited to, any of, for example, visual acuity, certain characteristic of the modulation transfer function, or of the point spread function.

Claims

WHAT IS CLAIMED IS1 . A device for examining the binocular vision, comprising: a laser channel configured to emit laser beams for ray tracing consecutively in time in parallel to the optical axis, cross-sections of the beam traces creating a beam pattern covering the aperture of the eye; a beam divider; a right-eye measurement channel and a left-eye measurement channel, optically connected to the laser channel via said beam divider, each containing a photosensitive matrix optically conjugated with an entrance aperture of the eye, a visually observable target with the ability to be conjugated with the retina, and a position sensing photodetector configured to measure a position of a laser beam projected onto a retina of the eye; a processing unit electrically connected to the laser channel and to the righteye measurement channel and to the left-eye measurement channels, said processing unit having a display at its output; and an electro-mechanical unit configured to align the distance between the righteye measurement channel and the left-eye measurement channel to correspond to the inter-ocular distance of a patient.

2. The device of claim 1 , further comprising a disparity calculation unit disposed between the processing unit and the display, said disparity calculation unit configured to operate with the processed data from the right-eye measuring channel and from the left-eye measuring channel.

3. The device of claim 2, wherein the processed data comprises signal levels, wave front aberrations and derivatives thereof, said derivatives comprising modulation transfer functions and the point spread functions.

4. The device of claim 1 , wherein the laser channel contains a single two- coordinate acousto-optical deflector connected to a driver operably controlled by a frequency synthesizer that is connected to and operably controlled by the processing unit.

5. The device of claim 4, wherein the frequency synthesizer is configured to generate frequencies that tilt the laser beams to produce two spatially separated beam patterns.

6. The device of claim 5, wherein one of said spatially separated beam patterns is configured to probe the right eye according to a time schedule for a right eye measurement after having propagated through the right-eye measurement channel and the other of said spatially separated beam patterns is configured to probe the left eye according to the time schedule of the left eye measurement after having propagated through the left-eye measurement channel.

7. The device of claim 1 , wherein the beam divider comprises a two-mirror roof with a right side to direct the right-eye laser beam pattern to the right-eye measuring channel, and with a left side to direct the left-eye laser beam pattern to the left-eye measuring channel.

8. A method for analyzing vision binocularity, comprising: comparing processed data from the right-eye measuring channel and from the left-eye measuring channel of the device of claim 1 by calculating correlation coefficients for the near and far vision of each eye between the wave front errors measured with eyes accommodated relatively using a common target in an open-field mode or separate targets of each measuring channel.

9. The method of claim 8, wherein the difference of said correlation coefficients for the right eye and for the left eye comprise the measure of aberration disparity of the fellow eyes.

10. A method for analyzing vision binocularity, comprising: comparing processed data from the right-eye measuring channel and from the left-eye measuring channel of the device of claim 1 by evaluating mirror asymmetry of wave front errors of the right eye and of the left eye by a module and an angle of the coma member of Zernike series.11 . The method of claim 10, wherein the mirror asymmetry of the wave front errors comprising another measure of aberration disparity of fellow eyes.

12. A method for analyzing vision binocularity, comprising: comparing processed data from the right-eye measuring channel and from the left-eye measuring channel of the device of claim 1 , wherein analysis comprises a potential involvement of anisocoria due to a planned surgery, said anisocoria simulated by controlling the beam pattern in a proportion of suggested results of the planned surgery.

13. The method of claim 12, wherein the beam pattern is generated by frequencies synthesized in the laser channel.

14. A method for analyzing vision binocularity, comprising: comparing processed data from the right-eye measuring channel and from the left-eye measuring channel of the device of claim 1 by describing a neurological summing potential by a binocularity vision index, wherein a zero value of the binocularity vision index is ascribed when the processed data corresponds to one of the eyes being blind, and the highest value of the binocularity vision index is ascribed when both eyes have equal values of the processed data, wherein intermediate values of said binocularity vision index are proportional to an amount of difference in the processed data between a dominant eye and a fellow eye.

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