CN115336967A - Method for obtaining retinal morphology - Google Patents
Method for obtaining retinal morphology Download PDFInfo
- Publication number
- CN115336967A CN115336967A CN202211139084.8A CN202211139084A CN115336967A CN 115336967 A CN115336967 A CN 115336967A CN 202211139084 A CN202211139084 A CN 202211139084A CN 115336967 A CN115336967 A CN 115336967A
- Authority
- CN
- China
- Prior art keywords
- path
- retinal
- obtaining
- propagating
- semi
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 31
- 230000004281 retinal morphology Effects 0.000 title abstract description 7
- 210000001525 retina Anatomy 0.000 claims abstract description 35
- 238000005259 measurement Methods 0.000 claims abstract description 31
- 238000012876 topography Methods 0.000 claims abstract description 26
- 230000000007 visual effect Effects 0.000 claims abstract description 24
- 230000004323 axial length Effects 0.000 claims abstract description 12
- 230000002207 retinal effect Effects 0.000 claims description 34
- 230000001902 propagating effect Effects 0.000 claims description 30
- 210000000695 crystalline len Anatomy 0.000 claims description 23
- 210000004087 cornea Anatomy 0.000 claims description 20
- 230000003287 optical effect Effects 0.000 claims description 10
- 210000004127 vitreous body Anatomy 0.000 claims description 8
- 210000001742 aqueous humor Anatomy 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 6
- 210000002159 anterior chamber Anatomy 0.000 claims description 4
- 210000003128 head Anatomy 0.000 claims description 3
- 239000012528 membrane Substances 0.000 claims description 2
- 208000001491 myopia Diseases 0.000 description 7
- 230000004379 myopia Effects 0.000 description 7
- 238000012014 optical coherence tomography Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000002595 magnetic resonance imaging Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 210000001747 pupil Anatomy 0.000 description 5
- 230000002265 prevention Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000004962 physiological condition Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B3/103—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for determining refraction, e.g. refractometers, skiascopes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/0008—Apparatus for testing the eyes; Instruments for examining the eyes provided with illuminating means
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/0016—Operational features thereof
- A61B3/0025—Operational features thereof characterised by electronic signal processing, e.g. eye models
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B3/1005—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for measuring distances inside the eye, e.g. thickness of the cornea
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B3/107—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for determining the shape or measuring the curvature of the cornea
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/15—Correlation function computation including computation of convolution operations
Abstract
The invention discloses a method for obtaining the shape of a retina, which comprises the following steps: constructing a measuring light path of a lens axis around the LENSTAR; constructing a semi-personalized human eye model according to the actually measured corneal topography and the axial length; obtaining the propagation path and the propagation angle of the light in the semi-linearized eye model under different visual fields by utilizing light ray tracing; and combining the light ray tracing result and the eye axis measuring result to obtain the retina coordinates under each visual field, and obtaining the retina morphology through corresponding fitting. According to the invention, a semi-personalized human eye model is traced according to clinical data of individual human eyes, and the method has great value for clinical application; the invention solves the difficulties of accurately obtaining the retinal morphology at present, and finally obtains the retinal morphology by means of instruments with higher clinical measurement speed and precision and corresponding software processing.
Description
Technical Field
The invention belongs to the technical field of visual optics, and particularly relates to a method for obtaining a retina morphology.
Background
With the high incidence and low age of myopia, more and more people seek effective means for myopia prevention and control. Aiming at the fact that myopic defocusing around the retina is an important research content for myopia prevention and control, accurate acquisition of the retina morphology can more effectively control and treat myopia. Therefore, the face information of the retina is obtained, and the method has important significance for theoretical research and clinical research of myopia prevention and control. The current multi-spectral refractive Topography (MRT) used clinically can give defocus at the retina, but cannot directly give the face parameters of the retina.
However, due to the structure of the human eye, there is currently no direct method for obtaining retinal topography clinically. The shape of the retina can be obtained only by indirect means, such as collecting the retina image by Magnetic Resonance Imaging (MRI), OCT (Optical Coherence Tomography), etc., and then performing corresponding image processing, or modifying corresponding eye axis measuring instruments (such as a super, IOLMaster (Carl-Zeiss meditec ag Jena, germany) and Lenstar (hag Streit, bern, switzerland)) and then performing corresponding data processing.
For Magnetic Resonance Imaging (MRI), the MRI can measure the retinal morphology in a large range, and the images have no problems such as distortion. However, MRI is expensive, measurement time is long, and MRI resolution is worse at 0.15mm.
For OCT, its measuring time is fast, and resolution ratio is high, need not direct contact eyes in the measurement process. But current research on myopia focuses more on the peripheral field of view, but the range of fields of view for OCT measurements is smaller. In addition, the result of the OCT measurement has problems such as distortion. Therefore, the method for obtaining the retinal topography by using the OCT is generally difficult, and no commercial OCT equipment for the retinal topography is provided at present.
For type a ultrasound, mainly by measuring the length of the eye axis and then fitting accordingly. However, it is necessary to contact the cornea of the subject at the time of measurement, and the result may be biased by pressing the cornea or even damage the eye. The measurement process is also slow, and the patient compliance has a large influence on the result. The precision is only 0.1mm, the myopia degree is increased by 3D when the eye axis is increased by 1mm according to the Arizona eye model, while the clinical optometry generally uses 0.25D as a boundary, and the measurement precision needs to be controlled within 0.1mm in brief conversion.
For some eye axis measuring instruments such as IOL MASTER and LENSTAR, which utilize the principle of partial coherence, the measuring time is fast, the resolution is high, and the instrument does not contact with glasses, but only the axial length on the axis can be measured. Research shows that LENSTAR has higher precision than IOL MASTER, and there are also methods for indirectly fitting the retinal topography by measuring the peripheral eye axis length through LENSTAR, but there are many places that are worthy of improvement in the fitting process, such as improvement in precision, simplification of the method, and closeness to the physiological condition of human eyes. Finding a method that can simply and accurately obtain the retina can therefore solve many of the difficulties that exist today.
Disclosure of Invention
The invention aims to provide a method for obtaining the retinal morphology, which has the advantages of wide measurement field range, simple operation process, low cost, quick measurement time and improved measurement precision.
In order to achieve the above object, the present invention provides a method for obtaining retinal topography, comprising the steps of:
constructing a measuring light path of a lens axis around the LENSTAR;
constructing a semi-personalized human eye model according to the actually measured corneal topography and the axial length;
obtaining the propagation path and the propagation angle of the light in the semi-linearized eye model under different fields of view by utilizing light ray tracing;
and combining the light ray tracing result and the eye axis measuring result to obtain retina coordinates under each visual field, and obtaining the retina morphology through corresponding fitting.
Optionally, constructing a lens peripheral axis measurement optical path includes: firstly, performing center calibration, and arranging an external center sighting target at a position superposed with a built-in center sighting target mirror image of the LENSTAR; subject was positioned in front of lemstar and kept head still and only eyes were turned; the length of the eye axis of the subject in each direction is measured by arranging a spectroscope so that the sighting target is imaged on the horizontal position of the subject, and the central sighting target is superposed with the built-in sighting target of the LENSTA.
Optionally, constructing a semi-personalized human eye model according to the measured corneal topography and the axial length includes:
measuring by using LENSTAR to obtain the thickness of an axial corner membrane, the depth of an anterior chamber, the thickness of a crystalline lens and the length of a vitreous body, and replacing corresponding parameters in an incident human eye model with the measurement result;
collecting corneal topographic map data, and performing corresponding fitting according to the topographic map data to obtain corneal surface type parameters;
and inputting the morphology parameters of the front and back surfaces of the cornea obtained after fitting into the eye model to obtain the incident semi-personalized eye model.
Optionally, the corneal topography fitting is calculated as follows:
wherein x and y represent the coordinates of the cornea, Z represents the height of the cornea, r is the curvature radius of the curved surface, k is the conic coefficient of the curved surface, and Z i (x, y) is the i term Zernike polynomial, A i Is the Z-th i Coefficients of the (x, y) term, i =1,2,3.. 30.
Optionally, the deriving the propagation path and the propagation angle of the light ray in the semi-linearized eye model under different fields of view by using the ray tracing includes: the method comprises the steps that a main ray is traced and enters a semi-personalized eye model, and the propagation path of the main ray in each structure in the model and the included angle between the main ray and an optical axis under each field of view are obtained; wherein the propagation path includes: a path Lc propagating in the cornea, a path La propagating in the aqueous humor, a path Ll propagating in the lens and a path Lv propagating in the vitreous body; wherein the optical axis contained angle includes: an angle α propagating in the lens and an angle β propagating in the vitreous.
Optionally, combining the ray tracing result and the eye axis measurement result to obtain the retina coordinates under each field of view includes: a path Lc propagating in the cornea, a path La propagating in the aqueous humor and a path Ll propagating in the crystalline lens are removed according to the actually measured axial length to obtain a new path Lv' propagating through the vitreous body; the corresponding retina coordinates under each visual field are obtained through calculation and calculated as follows:
x＝La·sin(α)+Lv′·sin(β)
z＝La·cos(α)+Lv′·cos(β)
where (x, z) represents the calculated retinal coordinates.
Optionally, the retinal topography fitting is calculated as follows:
wherein x ', z' represent the corrected retinal coordinates, R x Denotes the radius of curvature, k, of the retina in the horizontal direction x Is the retinal horizontal cone coefficient.
The invention has the technical effects that: the invention discloses a method for obtaining the shape of retina, which is based on the clinical data of individual human eyes, traces a semi-personalized human eye model and has great value for clinical application; the invention solves the difficulties of accurately obtaining the retinal surface type at present, and finally obtains the retinal morphology by means of instruments with higher clinical measurement speed and precision and corresponding software processing.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. In the drawings:
FIG. 1 is a schematic flow chart of a method for obtaining retinal topography in accordance with an embodiment of the present invention;
FIG. 2 is a diagram illustrating a ray tracing eye model according to an embodiment of the present invention;
fig. 3 is a diagram of an actual measurement optical path according to an embodiment of the present invention.
Detailed Description
It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer-executable instructions and that, although a logical order is illustrated in the flowcharts, in some cases, the steps illustrated or described may be performed in an order different than presented herein.
As shown in fig. 1 to 3, the present embodiment provides a method for obtaining a retinal topography, including the following steps:
constructing a measuring light path of the lens axis around the LENSTAR;
constructing a semi-personalized human eye model according to the actually measured corneal topography and the axial length;
obtaining the propagation path and the propagation angle of the light in the semi-linearized eye model under different fields of view by utilizing light ray tracing;
and combining the light ray tracing result and the eye axis measuring result to obtain the retina coordinates under each visual field, and obtaining the retina morphology through corresponding fitting.
Preferably, the construction of the lens peripheral axis measurement optical path specifically comprises:
the measuring light path is constructed before measurement. Center calibration is first performed and the outlying center visual target is positioned to coincide with the lens of the outltar's inner center visual target. Under the action of the spectroscope, the built-in central sighting target of the LENSTAR seen by the subject is superposed with the external central sighting target, and the superposition is taken as the fixation center.
The predicted off-axis field angles are horizontal 5 °, 10 °, 15 °, 20 °, 25 °, 30 °, 35 °; with its corresponding optotype positioned horizontally along the central optotype. As shown in fig. 3, the angle of view is θ, and the distance between each optotype and the center optotype is L. The distance D between the LENSTAR and the external central sighting mark is obtained by measuring with an infrared laser ranging pen, the corresponding sighting mark position under each visual field can be determined according to the formula tan theta = L/D, and an LED lamp is arranged on each sighting mark position.
The subject was positioned in front of the LENSTAR and held the head still and only turned the eyes. As shown in fig. 3, under the action of the spectroscope, the subject can achieve the off-axis fixation effect by fixing the image formed by the LED after passing through the spectroscope. At this time, the measuring light of LENSTAR is from the periphery of the eyes of the subject, and the measuring effect of the off-axis eye axis is achieved. In order to make the subject comfortable during the measurement and to obtain a larger pupil. Before the visual target is arranged, the LED lamp is wrapped by a black adhesive tape, and only a small hole for transmitting weak light is left.
The length of the eye axis in each direction of the horizontal direction of the subject is measured by arranging the spectroscope so that the sighting mark is imaged on the horizontal position of the subject, and the central sighting mark is superposed with the built-in sighting mark of the LENSTA R. The specific measurement is as follows: the length of the axis of the eye on the axis of the subject is measured, followed by measuring the right visual field of the patient and then the left visual field of the patient at intervals of 5 ° visual field. Results are the average of three measurements per field. After each visual field measurement, the testee is allowed to properly close the eye for rest, and the measurement effect of the next visual field is ensured.
Preferably, the constructing of the semi-personalized human eye model according to the actually measured corneal topography and the axial length specifically comprises:
the incident eye model was built in zemax from the navaro eye model.
The measurements of on-axis corneal thickness, anterior chamber depth, lens thickness and vitreous length are taken using the LENSTAR and replaced with the corresponding parameters incident on the human eye model.
And acquiring corneal topographic map data by using Pentacam, and performing corresponding fitting according to the topographic map data to obtain corneal surface type parameters.
Preferably, the corneal surface shape fitting formula is as follows:
wherein x and y represent the coordinates of the cornea, Z represents the corneal height, r represents the radius of curvature of the curved surface, k represents the conic coefficient of the curved surface, and Z represents the conic coefficient of the curved surface i (x, y) is a Zernike polynomial of the i-th term, A i Is the Z th i The coefficient of the (x, y) term, i =1,2,3.. 30.
And substituting the surface type parameters of the front and back surfaces of the cornea obtained after fitting into the eye model. Then the diameter of the entrance pupil is set to be 3mm, the wavelength is set to be 555nm, and the field of view parameters are set to be consistent with the measurement scene, so that an incident semi-personalized eye model is obtained.
Preferably, the following steps of obtaining the propagation path and the propagation angle of the light ray in the semi-linearized eye model under different fields of view by using the ray tracing are specifically as follows:
as shown in fig. 2: and (3) tracking the incident semi-personalized eye model by the chief ray to obtain the propagation path of the chief ray in each structure in the model and the included angle between the chief ray and the optical axis in each view field. Wherein the propagation path includes: a path Lc propagating in the cornea, a path La propagating in the aqueous humor, a path Ll propagating in the lens and a path Lv propagating in the vitreous. Wherein the included angle with the optical axis includes: an angle α propagating in the lens and an angle β propagating in the vitreous.
Preferably, the retina coordinates under each field of view are obtained by combining the ray tracing result and the eye axis measuring result, and the retina morphology obtained by corresponding fitting specifically comprises:
subtracting Lc, la and L1 obtained by tracking from the actually measured axial length to obtain a new path Lv' propagated by the vitreous body;
calculating the corresponding retina coordinates under each visual field by using a formula, wherein the formula is as follows:
x＝La·sin(α)+Lv′·sin(β)
z＝La·cos(α)+Lv′·cos(β) (2)
where (x, z) represents the calculated coordinates of the retina, and y is calculated similarly to the x method when the vertical direction is measured. The retinal coordinate (x) reached by the human eye with the on-axis light in the subsequent fitting process 0 ,z 0 ) As an origin, the retinal coordinate (x) on the axis is therefore determined 0 ,z 0 ) Set to (0, 0), the retinal coordinates of that other location are modified as follows:
x'＝x-x 0
z'＝z-z 0 (3)
wherein x is 0 And z 0 Representing the calculated retinal coordinates of the original on-axis points, (x ', z') representing the corrected retinal coordinates.
The preferred retinal surface type fitting formula is as follows:
wherein x ', z' represent the corrected retinal coordinates, R x Denotes the radius of curvature, k, of the retina in the horizontal direction x Is the retinal horizontal cone coefficient. Finally, fitting to obtain the face type parameter R of the retina x And k x 。
Transforming an LENSTAR eye axis measuring system and measuring the length of the peripheral eye axis;
the distance between the center sighting mark of the LENSTAR and the ceiling is 1.85m measured by an infrared laser ranging pen. The optotype is installed on the ceiling, the center optotype is installed at a position coinciding with the mirror image of the built-in center optotype of the lens, and the remaining optotypes are installed in the horizontal direction.
The field angle is set as: 5 °, ± 10 °, ± 15 °, ± 20 °, ± 25 °, ± 30 °; calculating the distance between each sighting mark and the center sighting mark as follows according to the formula tan theta = L/D: plus or minus 0.162m, plus or minus 0.326m, plus or minus 0.496m, plus or minus 0.673m, plus or minus 0.863m, plus or minus 1.068m; an LED lamp is arranged at each sighting mark position, and a subject can watch an image formed by the LED after passing through the spectroscope, so that the off-axis watching effect is achieved.
Before the visual target is arranged, the LED lamp is wrapped by the black adhesive tape, and only a small hole is left for transmitting weak light.
By arranging the spectroscope, the visual target is imaged in the horizontal direction of the testee by utilizing the refraction effect of the spectroscope, the testee is guided to measure the length of the axis of the eye on the axis, then the length of the axis of the eye on the right side is measured in sequence, and finally the length of the axis of the eye on the left side is measured. Three measurements are taken in each field and the average value is taken, and each measurement is completed by one field and the eyes are properly closed and rested.
The left eye data of subject 1 are measured as shown in table 1:
TABLE 1
| Field of view | Length of eye axis |
| 0° | 25.03mm |
| Nasal side 5 degree | 24.99mm |
| Nasal side 10 ° | 24.68mm |
| 15 degree on nose side | 24.17mm |
| 20 degree on nose side | 24.31mm |
| |
24.01 |
| 30 degree on nose side | 23.69mm |
| Temporalis 5 degree | 24.95mm |
| Temporalis 10 degree | 24.81mm |
| Temporolateral 15 ° | 24.49mm |
| Temporolateral 20 ° | 24.16 |
| Temporalis | |
| 25 degree | 23.88 |
| Temporalis | |
| 30 degree | 23.52mm |
Constructing a semi-personalized human eye model according to the measured axial length on the axis and the measured corneal topography data;
an initial incident eye model was built in zemax from the navaro eye model.
Corneal thickness on axis as measured by LENSTAR: 0.56mm, anterior chamber depth: 3.00mm, lens thickness: 3.51mm and vitreous length: 17.96mm replaces the corresponding parameters in the initial incident eye model. The incident eye model parameters were obtained as shown in table 2:
TABLE 2
| Surface type | Radius of curvature r | Coefficient of conicity k | Thickness of | Refractive index n | Abbe number |
| Anterior surface of cornea | 7.72mm | -0.26 | 0.56mm | 1.376 | 56.5 |
| Posterior surface of cornea | 6.5mm | 0 | 3.00mm | 1.3374 | 49.61 |
| Pupil of pupil | Infinity | 0 | 0 | 1.3374 | 49.61 |
| Anterior surface of the lens | 10.2mm | -3.1316 | 3.51mm | 1.42 | 48 |
| Posterior surface of crystalline lens | -6mm | -1 | 17.96mm | 1.336 | 50.9 |
| Retina | -12mm | - | - | - | - |
And acquiring corneal topographic map data by using Pentacam, and performing corresponding fitting according to the topographic map data to obtain corneal surface type parameters.
The preferred corneal surface shape fitting formula is as follows:
wherein x and y represent the coordinates of the cornea, Z represents the corneal height, r represents the radius of curvature of the curved surface, k represents the conic coefficient of the curved surface, and Z represents the conic coefficient of the curved surface i (x, y) is the i term Zernike polynomial, A i Is the Z th i Coefficients of the (x, y) term, i =1,2,3.. 30.
In zemax, the surface type of the cornea front and back surfaces was set to Zernike standard sag and Zernike coefficient parameters were set to 30 terms, the results obtained in table 3 were substituted into the model, the entrance pupil diameter was set to 3mm, the wavelength was set to 555nm, the field of view setting was matched with the case of eye axis measurement, and finally a semi-linearized incident eye model was obtained.
The ray tracing comprises a propagation path and a propagation angle of a principal ray in a semi-linearized eye model under different visual fields, a path Lc of the principal ray propagating in a cornea, a path La propagating in aqueous humor, a path L1 and an angle alpha propagating in a crystalline lens, and a path Lv and an angle beta propagating in a vitreous body under each visual field. The results obtained from the tracking are shown in table 3:
TABLE 3
| Visual field | Lc/mm | La/mm | Ll/mm | Lv/mm | Lv’/mm | Alpha/(radian) | Beta/(radian) |
| 0° | 0.560 | 2.996 | 3.510 | 17.958 | 17.964 | 0.015 | 0.016 |
| 5 degree on the nasal side | 0.562 | 3.002 | 3.515 | 17.889 | 17.911 | 0.086 | 0.089 |
| Nasal side 10 ° | 0.566 | 3.016 | 3.528 | 17.724 | 17.570 | 0.157 | 0.161 |
| 15 degree on nose side | 0.572 | 3.039 | 3.548 | 17.467 | 17.011 | 0.228 | 0.234 |
| 20 degree on nose side | 0.580 | 3.070 | 3.576 | 17.121 | 17.084 | 0.297 | 0.305 |
| |
0.590 | 3.110 | 3.610 | 16.691 | 16.699 | 0.367 | 0.376 |
| |
0.603 | 3.159 | 3.653 | 16.183 | 16.275 | 0.435 | 0.447 |
| Temporalis 5 degree | 0.561 | 2.998 | 3.512 | 17.932 | 17.879 | -0.054 | -0.056 |
| Temporolateral 10 degree | 0.563 | 3.009 | 3.521 | 17.812 | 17.716 | -0.124 | -0.128 |
| Temporolateral 15 ° | 0.568 | 3.028 | 3.538 | 17.600 | 17.356 | -0.194 | -0.199 |
| Temporolateral 20 ° | 0.575 | 3.055 | 3.561 | 17.297 | 16.968 | -0.264 | -0.271 |
| |
0.584 | 3.092 | 3.593 | 16.904 | 16.611 | -0.334 | -0.343 |
| |
0.596 | 3.137 | 3.632 | 16.425 | 16.154 | -0.404 | -0.415 |
And combining the light ray tracing result and the eye axis measuring result to obtain retina coordinates under each visual field, and obtaining a retina surface type through corresponding fitting.
Subtracting Lc, la and L1 in the table 3 according to the measured eye axis length in the table 1 to obtain new Lv' shown in the table 3;
calculating the corresponding retina coordinates under each visual field according to the following formula:
x＝La·sin(α)+Lv′·sin(β)
z＝La·cos(α)+Lv′·cos(β) (2)
wherein the coordinates calculated for the on-axis ray through the subject's eye and ultimately to the retina are: (x) 0 ，z 0 ) = (0.333, 21.471); the on-axis coordinates are corrected to (0, 0), and the coordinates of other fields are corrected correspondingly according to the following formula:
x′＝x-x 0
z′＝z-z 0 (3)
the resulting retinal coordinates are shown in table 4:
TABLE 4
| Field of view | (x′，z′) |
| 0° | (0，0) |
| 5 degree on the nasal side | (1.556，-0.128) |
| Nasal side 10 ° | (3.043，-0.645) |
| 15 degree on nose side | (4.407，-1.466) |
| 20 degree on nose side | (5.852，-1.759) |
| |
(7.101，-2.571) |
| 30 degree on nose side | (8.242，-3.4824) |
| Temporalis 5 degree | (-1.522，-0.114) |
| Temporolateral 10 degree | (-3.022，-0.405) |
| Temporolateral 15 ° | (-4.451，-0.987) |
| Temporolateral 20 degree | (-5.807，-1.685) |
| |
(-7.097，-2.433) |
| Temporalis 30 degree | (-8.269，-3.346) |
The coordinates of table 4 were fitted to the retinal surface type according to the following formula:
obtaining the curvature radius R of the retina in the horizontal direction by fitting x Is-11.34 mm, cone coefficient k x Is-0.1565.
The above description is only for the preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (7)
1. A method for obtaining retinal topography, comprising the steps of:
constructing a measuring light path of the lens axis around the LENSTAR;
constructing a semi-personalized human eye model according to the actually measured corneal topography and the axial length;
obtaining the propagation path and the propagation angle of the light in the semi-linearized eye model under different fields of view by utilizing light ray tracing;
and combining the light ray tracing result and the eye axis measuring result to obtain the retina coordinates under each visual field, and obtaining the retina morphology through corresponding fitting.
2. The method for obtaining a retinal topography according to claim 1 wherein constructing a lens peripheral ocular axis measurement optical path comprises: firstly, performing center calibration, and arranging an external center sighting target at a position superposed with a mirror image of an internal center sighting target of the LENSTAR; subject was positioned in front of LENSTAR and kept head still and only eyes were turned; the length of the eye axis in each direction of the horizontal of the subject is measured by arranging the spectroscope so that the sighting mark is imaged on the horizontal position of the subject, and the central sighting mark is superposed with the built-in sighting mark of the LENSTA R.
3. The method of obtaining a retinal topography of claim 1, wherein constructing a semi-personalized human eye model based on the measured corneal topography and axial length comprises:
measuring by using LENSTAR to obtain the axial corner membrane thickness, the anterior chamber depth, the lens thickness and the vitreous body length, and replacing corresponding parameters in the incident human eye model with the measurement result;
collecting corneal topographic map data, and performing corresponding fitting according to the topographic map data to obtain corneal surface type parameters;
and inputting the morphology parameters of the front and back surfaces of the cornea obtained after fitting into the eye model to obtain the incident semi-personalized eye model.
4. A method of obtaining a retinal topography according to claim 3 wherein the corneal topography fit is calculated as follows:
wherein x and y represent the coordinates of the cornea, Z represents the height of the cornea, r is the curvature radius of the curved surface, k is the conic coefficient of the curved surface, and Z i (x, y) is a Zernike polynomial of the i-th term, A i Is the Z-th i The coefficient of the (x, y) term, i =1,2,3.. 30.
5. The method for obtaining retinal topography according to claim 4, wherein deriving the propagation paths and propagation angles of light rays in the semi-linearized eye model for different fields of view using ray tracing comprises: the method comprises the steps that a main ray is incident into a semi-personalized eye model in a tracking mode, and the path of the main ray in each structure in the model under each view field and the included angle between the main ray and an optical axis are obtained; wherein the propagation path includes: a path Lc propagating in the cornea, a path La propagating in the aqueous humor, a path Ll propagating in the lens and a path Lv propagating in the vitreous body; wherein the optical axis contained angle includes: an angle α propagating in the lens and an angle β propagating in the vitreous.
6. The method of claim 5, wherein combining the ray tracing results and the eye axis measurements to obtain the retinal coordinates for each field of view comprises: removing a path Lc propagating in the cornea, a path La propagating in the aqueous humor and a path Ll propagating in the crystalline lens according to the measured axial length to obtain a new path Lv' propagating through the vitreous body; the corresponding retinal coordinates under each field of view are obtained by calculation as follows:
x＝La·sin(α)+Lv′·sin(β)
z＝La·cos(α)+Lv′·cos(β)
where (x, z) represents the calculated retinal coordinates.
7. The method of obtaining retinal topography according to claim 6 wherein the retinal topography fitting is calculated as:
wherein x ', z' represent the corrected retinal coordinates, R x Represents the horizontal radius of curvature, k, of the retina x Is the retinal horizontal cone coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211139084.8A CN115336967A (en) | 2022-09-19 | 2022-09-19 | Method for obtaining retinal morphology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211139084.8A CN115336967A (en) | 2022-09-19 | 2022-09-19 | Method for obtaining retinal morphology |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115336967A true CN115336967A (en) | 2022-11-15 |
Family
ID=83956170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211139084.8A Pending CN115336967A (en) | 2022-09-19 | 2022-09-19 | Method for obtaining retinal morphology |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115336967A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116616695A (en) * | 2023-04-07 | 2023-08-22 | 瑞尔明康(浙江)医疗科技有限公司 | Human eye optical characteristic acquisition method, large-view-field optometry device and optometry system |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2172471A1 (en) * | 1995-03-29 | 1996-09-30 | Hua Qi | Apparatus for and Method of Simulating Ocular Optical System |
| CN101069636A (en) * | 2006-05-09 | 2007-11-14 | 南开大学 | Cornea cutting depth calculation based on personalized human eye model |
| WO2009153929A1 (en) * | 2008-06-19 | 2009-12-23 | 株式会社トプコン | Optical image measuring device |
| CA2736784A1 (en) * | 2008-09-11 | 2010-03-18 | Iol Innovations Aps | System and method for determining and predicting iol power in situ |
| CN106324833A (en) * | 2016-09-07 | 2017-01-11 | 吉林大学 | Method of designing projection-type helmet objective lens with ideal retina imaging as target |
| CN107495923A (en) * | 2017-08-03 | 2017-12-22 | 苏州大学 | A kind of method for measuring eyeball retina form |
| US20220215584A1 (en) * | 2021-01-05 | 2022-07-07 | Translational Imaging Innovations, Inc. | Apparatus for Calibrating Retinal Imaging Systems and Related Methods |
| CN114911069A (en) * | 2021-02-10 | 2022-08-16 | 爱博诺德(北京)医疗科技股份有限公司 | Modeling method of retina periphery defocusing model |
-
2022
- 2022-09-19 CN CN202211139084.8A patent/CN115336967A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2172471A1 (en) * | 1995-03-29 | 1996-09-30 | Hua Qi | Apparatus for and Method of Simulating Ocular Optical System |
| CN101069636A (en) * | 2006-05-09 | 2007-11-14 | 南开大学 | Cornea cutting depth calculation based on personalized human eye model |
| WO2009153929A1 (en) * | 2008-06-19 | 2009-12-23 | 株式会社トプコン | Optical image measuring device |
| CA2736784A1 (en) * | 2008-09-11 | 2010-03-18 | Iol Innovations Aps | System and method for determining and predicting iol power in situ |
| CN106324833A (en) * | 2016-09-07 | 2017-01-11 | 吉林大学 | Method of designing projection-type helmet objective lens with ideal retina imaging as target |
| CN107495923A (en) * | 2017-08-03 | 2017-12-22 | 苏州大学 | A kind of method for measuring eyeball retina form |
| US20220215584A1 (en) * | 2021-01-05 | 2022-07-07 | Translational Imaging Innovations, Inc. | Apparatus for Calibrating Retinal Imaging Systems and Related Methods |
| CN114911069A (en) * | 2021-02-10 | 2022-08-16 | 爱博诺德(北京)医疗科技股份有限公司 | Modeling method of retina periphery defocusing model |
Non-Patent Citations (1)
| Title |
|---|
| 朱海丰;方志良;刘永基;: "人工晶体倾斜与偏心对人眼视功能的影响", 光子学报, no. 01, 15 January 2008 (2008-01-15) * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116616695A (en) * | 2023-04-07 | 2023-08-22 | 瑞尔明康(浙江)医疗科技有限公司 | Human eye optical characteristic acquisition method, large-view-field optometry device and optometry system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Guillon et al. | Corneal topography: a clinical model | |
| Carney et al. | Corneal topography and myopia. A cross-sectional study. | |
| Dubbelman et al. | The shape of the aging human lens: curvature, equivalent refractive index and the lens paradox | |
| Sorbara et al. | Metrics of the normal cornea: anterior segment imaging with the Visante OCT | |
| Mohamed et al. | Repeatability and reproducibility of pachymetric mapping with Visante anterior segment–optical coherence tomography | |
| US7744221B2 (en) | Method of eye examination by optical coherence tomography | |
| US7275827B2 (en) | Selective corneal aberrometry | |
| US10182719B2 (en) | Method for determining corneal astigmatism using optical coherence tomography | |
| Consejo et al. | Corneo-scleral limbus demarcation from 3D height data | |
| CN103142210B (en) | Peripheral refraction measuring method based on OCT technology | |
| Garcia-Feijoo et al. | New technologies for measuring intraocular pressure | |
| Mallen et al. | Measurement of retinal contour and supine axial length using the Zeiss IOLMaster | |
| CN115336967A (en) | Method for obtaining retinal morphology | |
| Tang et al. | A multicenter study of the distribution pattern of posterior-to-anterior corneal curvature radii ratio in Chinese myopic patients | |
| Sanchez‐Cano et al. | Magnification characteristics of the optical coherence tomograph STRATUS OCT 3000 | |
| Ogbuehi et al. | Repeatability and interobserver reproducibility of Artemis-2 high-frequency ultrasound in determination of human corneal thickness | |
| Clark | Variations in corneal topography | |
| Barkana et al. | Inter-device variability of the Stratus optical coherence tomography | |
| US20220215584A1 (en) | Apparatus for Calibrating Retinal Imaging Systems and Related Methods | |
| CN101069637A (en) | Retina pleochroism space-image modulation degree detection based on personalized eye model | |
| Jin et al. | Agreement of total keratometry and posterior keratometry among IOLMaster 700, CASIA2, and Pentacam | |
| Dunne et al. | Non‐invasive phakometric measurement of corneal and crystalline lens alignment in human eyes | |
| Douthwaite et al. | Surface tilt measured with the EyeSys videokeratoscope: influence on corneal asymmetry. | |
| Sahu | Corneal topography: sirius | |
| Ramamirtham et al. | Modelling eye lengths and refractions in the periphery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |