JPS6311130A - Apparatus and method for visually displaying cross-sectionalstate of cornea - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Background of the Invention The present invention provides a non-erosive ophthalmological means and technique for determining the physical dimensions of the eye and the use of the dimensional data thus obtained in corrective corneal surgery. It concerns its effective use in the implementation of

The human eye is an extremely powerful imaging device that produces images on the retinal surface. The imaging elements of the eye are the cornea and the lens. The cornea accounts for about 80 inches of imaging power (48 diopters), and the lens accounts for about 20% of the imaging power (12 diopters). In myopia, the eyeball is very elongated and oval in shape, and in this case the light rays are focused on a point in front of the retina and are therefore out of focus.

In the case of hyperopia, the imaging system is inadequate, and the focus and image are located behind the retina, which is therefore also out of focus. In the case of astigmatism, a focused or sharp image is not produced and the eye is essentially positioned behind or in front of the retinal surface (25).
The image is formed in the area of Myopia.

To correct hyperopia or astigmatism, glasses or contact lenses are used to focus images directly onto the cylinders and cones of the retina. Refractive keratoplasty, which surgically alters the shape of the cornea as described above, has previously been shown to achieve the same results instead of artificial correction (ie, glasses or contact lenses).

As an alternative to refractive keratoplasty techniques, keratinotomy and corneal sculpting are two types of corneal surgery that have received much consideration. In radial keratinotomy, 8 to 32 radial cuts are made in the cornea with a knife, which flattens the corneal curvature to such an extent that the focal point is placed at the back of the eye, preferably near the corneal surface. It has been shown. It has been demonstrated that such surgery can improve visual acuity by reducing objective myopia with an actual improvement of at most 12 days. This surgery reduces the depth of the incision to a fraction of a millimeter.
This is done by using a diamond or ruby knife with an adjustable belt or sleeve that can be controlled up to

The degree of myopia correction is determined by the depth of the cuts, the number of radial cuts, and the proximity of the cuts to the corneal center. Radial cuts and various other cuts have been combined to achieve other corrective effects.

By combining radial and circumferential cuts in different parts of the cornea, a characteristic flattening of the cornea is then possible, whereby a simultaneous reduction of myopia and astigmatism can be achieved.

Corneal sculpting consists of more advanced techniques that go beyond corneal incisions. This technique involves removing the outer layers of the cornea to affect the radius of curvature to increase or decrease the refractive power of the anterior surface of the cornea. By removing 0.15 to 0.25 mm of various layers from a 0.6 ran thick cornea, it is possible to correct myopia or hyperopia by up to 12 diopters, as well as extremely severe astigmatism (or corneal inhomogeneity). correction is possible. In fact, such corneal sculpting allows the outer surface of the cornea to have the radius of curvature of a corrective contact lens, as if the contact lens were inserted onto an imperfect cornea. It is the outer surface of the cornea, including the air/corneal interface, that increases or decreases the focal length (power) of the cornea and thereby changes the refractive state of the eye.

One clue to corneal sculpture is keratomylolysis (k
This is a technique called eratomileusis.

According to this, the outer part of the cornea is removed into a plano-convex button shape, frozen, and then placed on a micro lathe.

The corneal surface is shaped using a lathe under the control of a conveter until a predetermined corneal curve is obtained. The corneal button is then frozen and sutured to the patient's eye. In this way the external corneal curvature is altered by mechanical intervention.

Another clue to corneal carving is U.S. Pat. No. 552,98, filed November 17, 1983,
This is by laser incision as described in the specification of No. 3.

However, the fact is that whatever methods have been applied to the cornea to provide refractive correction, those that have been implemented or are proposed to be implemented are largely experimental. exists. There is no experimental basis that can be relied upon to predict with acceptable accuracy the ultimate refractive correction of the eye when applying a given technique to a given range of corneal dimensions. . And, particularly in the case of radial keratin incisions, there is still a risk that the incision will be made deep into the scar, thereby compromising the non-erosive nature of the surgery.

(2) SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved method and apparatus for use in assisting in non-erosive corneal surgery to provide refractive correction of the eye.

A particular object of the invention is to ophthalmological surgeons.

The objective is to provide corneal thickness and topography data, particularly for abnormal eyes.

The purpose of the present invention is to perform desired refractive index correction.
The object is to provide the above data in an easily interpretable format for determining the depth of the surgical incision and its surface distribution within the anterior surface of the abnormal cornea.

Another particular object is to achieve the above objects by means of a CAD/CAM visual display device that can selectively display the shape and thickness of the cornea for various postures.

Yet another particular object of the present invention is to display, for a selected position, the degree of corneal ablation required to achieve a particular refractive surgery, i.e., emmetropia (perfect visual acuity at a distance). The object of the present invention is to achieve the above object by means of a visual display device.

The present invention also provides computer-aided means for prescribing to a given eye the nature and extent of refractive corneal surgery required to render the eye completely or substantially emmetropic. The specific objective is to achieve the above objectives.

Yet another particular object is to answer the above points by means of computer aided means by which digital data can be obtained which are used to control an automated machine (29) for the performance of refractive surgery.

The above and further features include (1) determining the topographic map of the cornea of the eye in the form of digital data that is input and stored in a computer; (2) in the form of digital data that is also input and stored in a computer; (3) to determine the local thickness of the cornea along multiple axes; and (3) considered relevant to the anticipated surgery.

This is achieved by providing a CAD/CAM display of nine ranges of data suitable for the surgeon's display of selective corneal regions, directions or sections.

(3) Description of the Embodiments FIG. 1 shows all the elements for performing corneal evaluation and analysis and the elements involved in incision or sculptural keratoplasty based on this analysis.

The evaluation part is composed of three modules A, B and C. First, module A.

Determine the shape of the corneal surface of the eye. This module is an optical vision scanner or an optical keratometer that generates digital shape data at output 1o. Module A has the ability to rapidly scan from limbus to determine the entire shape of the outer surface of the cornea. This module accurately and clearly determines minute differences in the curvature of the external or internal optical region of the cornea. The module then has the ability to digitize data from multiple individual points on a particular cornea. Equipment suitable for use with Moji Neal A is located in Palo, California.
PKS-1000, commercially available from Sun Contact Lens Co., Ltd., a Japanese company with US offices in Aldo.
It is a photoceratoscope. The Sun photokeratoscope includes a photoanalyzer with a digital output that provides a visible display that can be generated to show the cross-sectional shape of the anterior surface curve for any cross-section that includes the central axis of the eye. It will be appreciated that connection 10 is for transmitting such digital output.

The second module B is a thickness measuring means (Pa
chy metric). Data is provided at output 11 as data generated by the ultrasonic distance measuring device and representative of the measuring instrument associated with the two position coordinate data. Thickness measurements may be made manually, point by point, using a commercially available portable transducer flexibly connected to a power source and display means. Such transducers are, for example, the Myocure Inc. Ultrasonic Thickness Gauge, manufactured by Myocure Inc., Los Angeles, Calif., or the CILCOI Inc., available from its Huntington, West Virginia, office.
nc, ) made by [Vlaseno J (” Vi 1lase
nor').

When using such a device, the fixed target ensures that the patient's untested eye remains centrally stable relative to the tested eye, no matter where the glove is placed on the corneal surface from the central optical axis to the periphery. can maintain sex.

Preferably, the display shown in FIG. 3 (ie, front view) is selected. This display includes a manually operable cursor for selecting and specifying the assumed coordinate position of each corneal thickness measurement (29) application point.

The thickness measurements for each different point identified by the cursor are entered into a calculator in module C and stored. Typically, thickness measurements are taken at five points along each of several selected meridians passing through the central axis of the eye. It is also desirable that the direction of the observed corneal astigmatism (as seen from the display of the shape data generated by the module A in FIG. 3) is in the direction of the central meridian of the thickness measurement. And second. Preferably, a third successive series of thickness measurements are taken along meridians each offset at 20 degrees in opposite directions relative to the central thickness meridian. Furthermore, the five thickness measurements on the central meridian are (a)
This is done at both outer ends that are about one point shorter than the intersection with the periphery, (b) at the center (on the optical axis of the eye), and (c) at the midpoint between the center and both outer ends.

For the 25) meridians, each offset by ±20 degrees from the central meridian, only four measurements (i.e. at the outer edges and midpoint) are required. This is because the thickness measurement at the center or optical axis portion only needs to be performed once.

Therefore, even if the meridian scans above 25) are performed, they will overlap.

The third module C is constituted by a computer to which digital data of the shape (connection 10 from module A) and digital data of thickness (connection 11 from module B) are supplied. This calculator may be, for example, an IBM PC computer, as shown selectively and schematically in FIGS. 2, 3 and 4.

It has the ability to display the cornea evaluated in Module C in a CAD/CAM format. The schematic diagram in Figure 2 is a cross-sectional view of the entire cornea along one meridian (at least from the periphery to the periphery), and the calculator provides a "close-up" view of the details of a selected portion of the overall cross-sectional view.
This makes it possible to accurately examine the local shape and thickness of the cornea. It will be appreciated that it has the ability to increase the scale of the cross-sectional representation.

Digital data provided to module C via connections 10-11 is used for selective CAD/CAM display techniques as suggested in FIGS. 3 and 4. In FIG. 3, the cornea is shown from the front to the back (i.e., the front view).

and is shown graphically with a plurality of alternating rings representing progressively increasing thicknesses.

Further, in FIG. 4, the cornea is shown in a perspective view, representing the contour shape of FIG. 3 using an accurate perspective drawing. The perspective view of Figure 4 shows that, in combination with the ability to selectively rotate the screen by appropriate software within the calculator, the surgeon can
It will be appreciated that a direct anterior view of the cornea can be obtained by viewing the adult cornea for evaluation on the RT screen. Additionally, by using appropriate software, the various views 2, 3 and 4 can be adjusted to determine the direction or angle of the view, the local corneal thickness curvature (anterior or posterior surface) for a point or series of points on the corneal surface. ) or may include numerical data providing a numerical description such as diopter capacity. It will also be appreciated that such numerical data may be available in hard copy printouts at any stage of corneal evaluation, as well as in various displays.

Module D in FIG. 1 combines the shape and thickness measurement data supplied by module C with additional digital data on the idealized shape from module E or digital data from the surgical evaluation data puncture of Mononeal F. Provide additional CAD/CAM displays (eg, as in FIG. 5 or FIG. 6) that utilize additional digital information from other sources. A computer memory in module E, which may be incorporated into a disk device that can be used as a data source for some of the displays in module D, includes information on the refractive index of the eye being evaluated for surgical keratoplasty. On the other hand, digital data on the corneal shape of an idealized eye that can generate an emmetropic eye is stored. This digital data includes the axial length of the eye as determined by A-scan ultrasound sonography, the age and sex of the patient, the internal pressure of the eye, and any other similar or It is stored taking into account factors that allow a detailed comparison of the projection image of an idealized emmetropic eye model with the same measurement parameters and the eye to be evaluated. patient's age and sex, axial (anteroposterior) length of the eye (number of tenths fl), internal pressure of the eye, desired synthetic refractive index conditions (e.g. -1,50 diopters, -1
. ) is input to module E, module D
, from the digital data accumulated for the idealized eye, additionally the selected corneal shape of the idealized eye along the selected meridian for the shape display of the measured data in module D. It becomes possible to generate a display. This feature allows the idealized eye meridian shape to be evaluated relative to the representation of the meridian shape of the meridian data (from connections 10-11).

In more detail, FIG. 5 shows a module D display in which the eye being measured is myopic. Here, the corneal shape 12 of the displayed meridian section of the eye to be examined is more curved and has a smaller flatness than the corneal shape 13 of the meridian section displayed at the ideal northern limit. In the situation, shape 1 of shape 13
It is desirable that the arrangement directions on the two surfaces intersect near the peripheral edge. Therefore, in FIG. 5, the shape 12-1
The intersection points 14-15 of 3 are symmetrically offset to the opposite side of the optical axis 16, and the crescent-shaped cross section between shapes 12-13 shows whether the cornea is shaped like 12 if the corneoplasty is performed.

Figure 13 shows the part to be cut out, which is performed by a laser or other engraving reduction means. And if keratoplasty is performed with a radial corneal incision with a laser or knife incision, shape 13 indicates the target curvature necessary to produce corneal curvature correction to achieve or approximate post-operative emmetropia. It is something.

On the other hand, FIG. 6 shows a module D in which the eye to be examined is farsighted. That is, here, the corneal shape 12' of the eye to be examined in the meridian cross section is flatter and less curved than the corneal shape 13' of the ideal eye in the meridian direction.

In this situation, it is desirable to arrange the shape 13' on the shape 12' so that their intersection occurs only at the intersection with the optical axis 16. Also shape 12'-1
The annulus thus represented by the cross-sectional area between 3' indicates the portion that would be removed if the cornea were carved from the cross-sectional shape 12' to the cross-sectional shape 13'.

FIG. 1 further shows that in place of the idealized shape data supplied by module E, or data suitably combined and averaged with these, a further module F provides a record of the surgeon's own experience. A datapunk representing the totality of such records from a central datapunk for servicing a given regional or national hospital or ophthalmology institution is available.

Therefore, (1) he believed that his surgical skills would allow him to make eight radial cuts of length 3 mm extending from the medial end 2 + raR to the lateral end 5 with a uniform depth of 0.52 mm. After performing a surgery such as an incision.

(2) used the analyzer of FIG. 1 to reexamine the eye after corneal surgery, and (3) selected the analysing shape 12 to approximately match the idealized eye shape 13. When he knows that he has placed on the meridian, he can store the relevant i9 parameters of the eye before and after surgery in the memory in module F along with the relevant ie parameters for his surgical procedure. Other observations regarding the long-term effects that can be attributed to the surgery can also be accumulated in Module F when the same eye is examined later. Recorded data as described above can also be entered into the memory of module F, along with the surgeon's use of other techniques to ensure the same or substantially equivalent results for different patients.

Over time, datapunk forms a pool of experience in which two alternative techniques and their after-effects can become part of the available background for optimal decision-making before surgery. The recall of data from module E and/or module F for display in module D is accompanied by a two-dimensional graphical representation of the selected meridional cross-section.
(a) Related aspects of the involved eye (before and after surgery)
It goes without saying that it may also include (b) parameters and precautions regarding the surgical procedure used and (c) textual representation of observed long-term side effects.

Another application No. 552, 98 filed by the same applicant
If you decide to use an automatic laser scanning device such as that described in Section 3 to perform corneal surgery, you will be required to use a The accumulated decision data for the meter is available for application in its entirety (or with careful modifications) via module D. Therefore, the output line 18 from module D to module G is
It will be understood that the use of parameters such as control parameters and parameters via module G for automatic surgery of laser incision/engraving deflection is shown. It will be appreciated that the stored and available parameter data provided via connection 18 includes such laser surgical data as power level, exposure rate (i.e., laser husks repulsion rate), spot size, etc. Good morning. And post-operatively, the surgical/F parameter data and the before/after ocular data are stored in module F data punctures if the surgeon determines that the success of the surgery (or other outcome) warrants data retention. It is possible to store.

It will be appreciated that the apparatus and method described above meet all of the objectives set forth above and herald a major change in the approach to the correction of corneal refractive problems. The purpose of ocular measurements is to describe the corneal shape.

It will be appreciated that the creation of a digital database that is descriptively available for displaying any number of meridional sections. These data are available in both graphical and textual representations.

Experience can improve the quality of a well-informed basis for decision-making prior to surgery. The digitized decision data can be used directly for modeling incisions (whether radial or fully sculpted) or for automatic setting of incision or resection directions. This data is displayed on a hard copy printout or CRT screen to guide the surgeon's incisions or direct the incision or engraving laser system.

Automated use of module G allows a single surgical procedure to be performed to produce a global refractive correction as indicated by a display such as that of FIG. 5 or FIG. Alternatively, and until the surgeon finds sufficient confidence in the use of automated surgery, he may modify the surgery in a conservative direction by removing only a small fraction, e.g. half, of the corneal tissue that appears to be removed. It might become. In this latter case, he can perform a measurement evaluation of the other eye before deciding to perform the remaining half of the total surgery.

In other words, by automating tissue removal and following each turn up to half of the programmed variable removal depth, he will know what refractive correction has to be achieved and will therefore save half the remainder of the surgery. (i.e. the surgery in Figure 2) of the same part (a) of the programmed variable depth (
b) Be able to judge whether it should be done on a larger part or (c) a smaller part.

An important feature of the invention is that the corneal evaluation/analysis modules A and B
and a data puncture function that replenishes the measurement data from C. Module D allows a comparative display of the evaluation/analysis data in relation to the data puncture output obtained from module F. Importantly, these data allow the converter in module D to determine the length and depth of the radial keratin incision (MT” incision or rel.
axing limbal surgery) or any combination of incisional refractive surgery currently available from around the world. In this way, the computer allows the surgeon to make the eye emmetropic, slightly myopic, or slightly hyperopic, reducing refractive errors - whether they are myopic, hyperopic, or astigmatic. Can suggest a course of surgical action. In this way, the surgeon can choose whether or not to accept computerized recommendations derived from two national views or from an extensive database regarding his surgical intervention for that particular cornea. As the surgeon increases his skill and number of surgeries, his specialized manual surgical techniques are factored into a completely separate and unique feature for him. As his personal database grows, the computer can recognize his penchant for slightly deeper incisions, wider incisions, or other idiosyncrasies of this individual technique. Thus, by inserting a glass "credit" card, the calculator can recognize the individual surgeon and call up his special database or even wider hospital, city-wide or larger databases. Become. All computer correction suggestions to produce the final result on a specific ray refraction after surgery are displayed in CAD/CAM format and can be printed out as hard copy. Computerized heel suggestions adopted and validated by the surgeon can also be immediately printed for use by the surgical attendant.

The currently available thickness measuring instruments described above are intended to measure the corneal thickness at multiple locations on the corneal surface, including multiple locations (for example, 5 locations) along a given meridian cross section. Even with this relatively small number of points on two curved surfaces, a valid representation of the curved surface can be established. It will be appreciated that this is possible by reference to much more precisely developed shape data especially for the anterior surface of the cornea.

Accurate external surface data captured by this relatively small number of points allows surgeons to
/In the CAM display, the concave shape of the cornea matches the model - whether it is a meridional section (Figure 2), a front view (Figure 3) or a rotated three-dimensional model (Figure 4). When viewed, one can obtain reasonably accurate digital data regarding the concave shape of the cornea. In the case of the model shown in Figure 4.

Contains "wire-linked" models of both concave and convex shapes offset from each other by the measured thickness value, or displayed with the measured values emphasized (but with a scale), e.g. by a factor of 2 or 10. good.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically illustrating the apparatus and manual operating steps involved in the present invention.
Figure 1 is a simplified diagram showing an alternative representation in module C of Figure 1; Figures 5 and 6 are CAD/C in module D in Figure 1.
2 is a simplified diagram showing an alternative to AM display; Module A: Corneal surface shape (digital output data) Module B: Corneal thickness measurement (digital output data) Module C: Computer memory display module D: CAD/CAM and display module E: Idealized shape (digital output data) Module E': Measuring eye parameter data module F
: Functional evaluation data Puncture module G: Laser engraving means (power level, spot size, exposure or repeated periodic deflection)

Claims (1)

[Scope of Claims] (1) A shape-measuring element including means for providing digital output data representing measurements of the corneal surface shape, and measurements of local corneal thickness at different predetermined positions on the corneal surface. a thickness measuring element including means for supplying digital output data representative of the thickness of the thickness measuring element; storage means connected to the output of each of said elements for storing respective digital output data; and a calculator connected to said storage means, said thickness measurement element a non-erosive ophthalmological device for visually displaying a cross-sectional shape of the cornea, comprising: display means for producing a computer-assisted display of the computed shape and thickness data; (2) The apparatus according to claim 1, wherein the display means includes means for generating a two-dimensional shape representation of the measured meridian section of the cornea. (3) The apparatus of claim (2), wherein said display means includes selectively operable means for changing the meridian to which the display applies. (4) The display includes thickness data and/or curved surface data and/or numerical values representing refractive power at predetermined intervals or positions on the displayed shape (
The device described in 1) or (2) or (3). (5) The computer further comprises storage means having an averaging capability for accumulating experience of shape and thickness data as a function of achieving emmetropia.
, (2), (3), or (4). (6) The display means displays a contour representing an equal curved surface in a plurality of meridian planes at a predetermined stepwise increasing point of the curved surface and/or an equal corneal thickness at a predetermined stepwise increasing point of the curved surface. Claims (1) to (5) comprising means for generating a two-dimensional polar projection representation of the contour.
The device described in any of the above. (7) The device according to claim (6), wherein the display includes a numerical display of thickness data at predetermined interval positions within the display and/or a numerical display of curved surface data at predetermined interval positions within the display. . (8) A corneal engraving photoablation laser and a laser control means operatively connected to said two storage means for determining the operation of the laser in response to the stored data. ) to (7). (9) The shape measuring element is a photokeratometer (photok).
eratometer) and/or an optical ocular scanner, and/or said thickness measuring element comprises an ultrasonic pachymeter.
) The device according to any one of claims (1) to (8). (10) (a) Step of determining and digitizing the shape of the cornea with the optical axis of the eye as a central reference, and storing the digitized shape data in the computer memory; (b) From the stored digital shape data. (c) generating on said display a linear marker line consisting of a cursor movable along a meridian passing through the center of the display in a predetermined direction; (d) selecting a pachymeter having a transducer adapted to contact said cornea locally to produce a digital measurement of corneal thickness; and (e) said marker. placing a transducer at a position on the cornea corresponding to a point on the line; (f) placing a cursor at said point; and (g) converting digital thickness data from said thickness measuring device into a calculator. (h) repeating steps (e) (f) and (g) for one or more separately selected points on said marker line; (i) storing; visualizing the cross-sectional condition of the cornea of the eye using a digital calculator, comprising: generating from the digital shape and thickness data obtained a coordinated representation of the corneal shape and thickness measured along said meridian; How to display. (11) (J) A step of accumulating digital data on the corneal shape of the ideal eye, which is the goal that the emmetropic eye should achieve, in a computer memory based on the parameter data measured for the given eye; (K) the above-mentioned generating an additional representation of the corneal shape of the idealized eye along the meridian from stored digital data of the idealized eye, said additional representation being aligned with or superimposed on the aligned representation of step (i); 11. The method of claim 10, further comprising the step of: performing a visual comparison between the measured corneal shape and the idealized corneal shape along the meridian. (12) said meridian is one of a plurality of meridians for each of which a linear cursor movement is generated through the center of the display of step (c), and at a plurality of points along each of these meridians; Correspondingly, a corneal thickness measurement is taken and stored in a computer memory so that said or each aligned representation is aligned with the selected one or more meridians along which the corneal thickness measurement is taken. The method according to claim (10) or (11), which is performed on. (13) The axial direction of the astigmatism is confirmed, and the selected plurality of meridian directions are at least three, and the three directions are selected at approximately equal angular intervals, and the astigmatism is concentrated in the astigmatism axis direction. The method of claim (12) as applied. (14) If a given eye is hyperopic and therefore the process (
If a more curved and less flat idealized meridian shape is required than that represented in the representation of i), step (K)
Claim (11) or (12), wherein the superimposed display of is arranged such that the idealized eye meridian-shaped ocular axis intersection coincides with the meridian-shaped ocular axis intersection of step (i).
the method of. (15) Since the given eye is myopic and has difficulty, the process (
If an idealized eye meridian shape that is flatter and less curved than that represented by the representation in step (i) is required, the idealized eye meridian shape is symmetrical on the opposite side of the eyeball axis from the meridian shape in step (i). Claim (11) or (12), wherein the superimposed display of step (K) is arranged so as to intersect at a plurality of points close to but not reaching the periphery of the cornea.
the method of. (16) Keratoplastic surgery, including radial keratin incision or laser engraving photoablation of the anterior corneal surface, is performed on the eye with the purpose of correctively altering the corneal shape, particularly along said meridian, and Thereafter, each step is performed again, so that the corneal shape and thickness measurements before and after the surgery can be visually compared.
15) Any method. (17) A step of accumulating digital corneal shape data of multiple eyes that have achieved emmetropia following keratoplasty surgery in the memory of a computer, and supplying the accumulated data of the multiple eyes as digital shape data for the ideal eye. generating an additional representation of the corneal shape of the ideal eye along said meridian from the digital data accumulated for the idealized eye, said additional representation being consistent with step (i); the corneal shape measured along the meridian and the idealized corneal shape, thereby making a comparison between the corneal shape measured along the meridian and the idealized corneal shape. ) either way. (18) a digital computer; means for determining and digitizing a corneal shape having a center reference with respect to the optical axis of the eye; and storing the digitized shape data in the computer memory; means for producing a front view centered representation; and on said representation;
A thickness meter having means for generating a linear marker line movable with a cursor in a selected direction along a meridian passing through the center of the display, and a transducer for digitally measuring corneal thickness, the transducer comprising: placed in a position corresponding to one or more points on said marker line on said marker line and applied in local contact with the cornea with said cursor positioned at said point; means for inputting digital thickness data from a pachymetry device corresponding to one or more points on the cornea along said meridian from the stored digital shape data and thickness data; and means for providing a coordinated representation of the shape and measured thickness. (19) a digital computer; means for determining and digitizing the anterior surface shape of the cornea as a three-dimensional curved surface; and storing the digital shape data in the memory of said computer; Digital data of the anterior surface shape of the idealized cornea, which is the objective to be achieved, is stored in the memory of the computer as another three-dimensional curved surface. means for applying an ultraviolet laser beam to the anterior surface of the cornea for selectively photolytically ablating the anterior surface of the cornea; and means responsive to computer-stored data for controlling a laser beam to form said other curved surface by volumetrically removing and penetrating into the stroma, the method comprising: modifying the curved surface of the anterior surface of the cornea; A device that correctively improves the optical characteristics of the eye. (20) (a) determining and digitizing the shape of the anterior surface of the cornea as a three-dimensional curved surface and inputting the digital shape data into computer memory; and (b) determining the optical improvement of the measured parameter data of the eye. Digital data of the anterior surface shape of the idealized cornea, which is the objective to be achieved based on (c) irradiating the anterior surface of the cornea with an ultraviolet laser beam to selectively photolytically ablate the anterior surface of the cornea; and (d) using the computer-stored data to control a laser beam to volumetrically remove tissue from the anterior surface and form the other curved surface by penetrating into the stroma. A method of orthodontically improving the optical properties of the eye by changing the curvature of the anterior surface of the cornea. (21) The method according to claim (20), wherein emmetropia is the objective of step (b). (22) The goal of step (b) is a three-dimensional curved surface that represents a predetermined partial change in the direction of achieving the ultimate optical characteristics of an emmetropic eye for the target eye; Claims 1 and 2 provide an opportunity to evaluate the optical and/or geometrical characteristics of the eye in order to determine the degree to which the partial modification achieved after completion of step (d) corresponds to its prior determination. 20) method. (23) The method of claims (20), (21) and (22), wherein separate visual representations are generated for corresponding views of the accumulated digital data of steps (a) and (b). . (24)(e) An optical determination is made as to whether step (d) produced a substantially emmetropic eye, and if substantial emmetropia was achieved, the cornea thus improved. A digital determination is made about the shape of the front surface of the front surface of the ) through (d) are one of a plurality of inputs, each applicable to a different eye to produce a substantially emmetropic eye, and (f) a plurality of eyes accumulated to provide shape data for the ideal eye. and (g) using the ideal eye data of step (f) in step (b) for subsequent execution of the method in application to other eyes. range (2
Methods 0) to (23). (25) Using a digital computer, the optical characteristics of the eye are corrected and improved by changing the curved surface of the anterior surface of the cornea so that it approximates the digital definition of the idealized three-dimensional anterior surface curved surface stored in the computer. A method comprising: (a) determining and digitizing the surface shape of the cornea as a three-dimensional screen and storing the digital shape data in the memory of the computer; and (b) storing the shape data and the digital definition. and generates a numerical description representation describing the spherical and cylindrical components of the difference between the determined surface and the idealized surface, such that this represented numerical description is also idealized from the determined surface. (c) applying ultraviolet light to the anterior corneal surface to selectively photolytically ablate the anterior surface of the cornea; (d) directing a laser beam to volumetrically remove tissue from the anterior surface and penetrate into the stroma to achieve a modification of the surface curvature to approximate the idealized surface curvature; using data stored in a computer for control purposes. (26) The method according to claim (25), wherein the numerical description is in diopters. (27) the modification of the numerical description is stored in the memory of the computer and used as the basis for the control of step (d); The method of claims (25) and (26) in the form of a digital definition of the front surface. (28) The computer-stored digital definition of the idealized surface is the product of a memory bank that reflects input specific to previous corneal sculpting surgeries considered successful. ) and method (27). (29) A method using a digital computer to correct and improve the optical properties of the eye by performing radial keratin incisions on the anterior surface of the cornea, the method comprising: (a) measuring the shape of the anterior corneal surface as a three-dimensional curved surface; (b) inputting into the computer memory a program of radial incisions through the anterior surface of the cornea to the stroma; (c) exposing the cornea to light at respective portions of a plurality of angularly spaced locations on the anterior surface, further predetermined to improve the measured optical properties of the eye; (d) irradiating the anterior surface of the cornea with an ultraviolet laser beam for selective removal by decomposition; using the program to control a laser beam. (30) Following step (d) the eye is measured again for its optical properties and the digital data for the measurements before and after step (d) and for the program are entered into a memory bank and the digital data for the different eyes are 29. The method of claim 29, wherein the method is made accessible for subsequent use in performing step (b) in a subsequent radial keratotomy procedure. (31) A method using a digital computer to correctively improve the optical characteristics of the eye by changing the curved surface of the anterior surface of the cornea, the method comprising: (a) measuring the shape of the anterior surface of the cornea as a three-dimensional curved surface; (b) generating from the accumulated digital shape data a front view of the cornea with the identified center; (d) inputting into computer memory digital data for an idealized corneal shape whose goal is to achieve emmetropia; (e) generating a matched representation of both curved surfaces along said meridian from the digital data stored for the measuring eye and the ideal eye, the computer memory containing digital data for definition; (f) selectively photolytically removing the anterior surface of the cornea; (g) controlling the laser radiation to volumetrically remove tissue from the anterior surface and approximate an ideal curved surface by penetrating the stroma; and a step of using the computer accumulated data. (32) The meridian marker line of step (c) is selectively rotatable around the display center, so that step (e)
A method according to claim 31, wherein astigmatism is clearly visible during the aligned display of the image. (33) If a given eye is hyperopic and therefore requires an ideal eye meridian shape that is more curved and less flat than the ideal eye meridian shape, then the ocular axial chiasm of the ideal eye meridian shape is 33. The method of claim 31 or 32, wherein the display of step (d) is aligned to coincide with the meridian-shaped ocular chiasm. (34) If a given eye is myopic and therefore requires an ideal eye meridian shape that is less curved and flatter than the ideal eye meridian shape, then the ideal eye meridian shape is the same as the measured eye meridian shape. or (31), wherein the alignment of the representations of step (d) is positioned so as to intersect at a plurality of points symmetrically spaced on opposite sides of the optical axis and intersecting near and shorter than the periphery of the cornea. 32) method. (35) Using a digital computer, the optical characteristics of the eye are corrected and improved by changing the curved surface of the anterior surface of the cornea so that it approximates the digital definition of the idealized three-dimensional anterior surface curved surface stored in the computer. an apparatus for determining the surface shape of the cornea as a three-dimensional screen, digitizing the surface shape, and storing the digital shape data in the memory of the computer; and a curved surface determined from the shape data and the digital definition. and generate a numerical description representation describing the spherical and cylindrical components of the difference between the idealized surfaces, whereby this represented numerical description also approximates the idealized surface from the determined surface. means for directing an ultraviolet laser beam to the anterior surface of the cornea for selectively photolytically ablating the anterior surface of the cornea; Using computer-stored data to control laser irradiation to achieve a modification of the surface curvature to approximate the idealized surface curvature by volumetrically removing tissue from the anterior surface and penetrating into the stroma. A device comprising means, and. (37) A device for correctively improving the optical characteristics of the eye by changing the curved surface of the anterior surface of the cornea, which measures and digitizes the shape of the corneal surface as a three-dimensional curved surface, and which measures and digitizes the shape of the corneal surface as a three-dimensional curved surface. means for storing data in a memory of the computer; means for generating, from the stored digital shape data, a frontal representation of the cornea with the center identified; and a linear marker line on the representation along a meridian passing through the center of the representation; means for displaying the image in a predetermined direction; means for inputting into computer memory digital data for an idealized corneal shape that the emmetropic eye is a goal to achieve; producing a matched representation of both surfaces along said meridian, whereby the computer memory contains digital data for definition and said matched representation is adapted to approximate the measured surface to the ideal surface; means for visually indicating the characterized volumetric removal of corneal tissue required; means for directing an ultraviolet laser beam to the anterior surface of the cornea for selectively photolytically removing the anterior surface of the cornea; and means for using said computer storage data to control laser radiation to approximate an ideal curved surface by volumetrically removing and penetrating the substrate.