JPH02172461A - Changing method for optical characteristic of eye, product used therefor, making thereof, and stocking-collection or kit with its product - Google Patents

Abstract

PURPOSE: To obviate the necessity of microprocessor control to change spot dimensions, by providing a specific form beam-impermeable film of disposable element, which is placed selectively in the middle of laser-beam radiation to cornea in a keratotomy. CONSTITUTION: A film 16 of thickness distribution precharacterized properly can be placed selectively in the path of laser-beam radiation of an axis 15. The removable maximum thickness of the film 16 depends on the maximum limit of intrusion of laser-beam into the corneal matrix accompanying a specific correction process. Appropriate materials for the film 16 include a polyimide, and poly(ethylene terephthalate). By means of the film 16, laser carving of the corneal surface can be conducted by adjustable spot dimensions without necessitating microprocessor control for changing the spot dimensions. Further, subject to the optical change to be achieved, a precharacterized disposable film can be selected from the stock to perform an ophthalmic operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to ophthalmic surgery involving surgery on the outer surface of the cornea.

[Conventional technology]

Surgeries of the required nature include corneal transplants and corneal incisions, which traditionally require skilled manipulation of cutting instruments. However, with the sharpness of the cutting blade, the mere entrance of the blade to the surface of the cornea results in a wedge-shaped lateral pressure on the body cells displaced by the entrance, both on the artificial surface. Such lateral pressure
There is a limit to the number of layers of cells on both inlet steels that damage and reduce the formation of scars that have to be healed, resulting in a structure of scar tissue. November 17, 1983
The inventor's original patent application number 552, filed in
No. 883 includes a background discussion of the effects of various effective wavelengths of laser radiation on ophthalmic surgery, particularly surgery performed on the anterior surface of the cornea.

It has been explained that radiation at ultraviolet wavelengths is desirable due to its high photon energy. This energy has a large impact on tissue, causing tissue molecules to be broken up by photon bombardment, resulting in photolytic tissue removal. The molecules at the irradiated surface are broken into small volatile fragments without damaging the remaining substrate, and the mechanism of removal is photochemistry, ie, direct decomposition of intramolecular bands. Photothermal and/or photocoagulation effects are not unique to ablation at ultraviolet wavelengths and are not observed, and cell damage upon ablation is negligible.

The above-mentioned related application deals with various concepts whereby laser radiation at ultraviolet wavelengths below 200 nm is controlled to deliver the laser radiation to the visually used area of the anterior surface of the cornea and to the stroma. It penetrates and achieves a predetermined volumetric removal of corneal tissue, thereby correctively altering the contour of the anterior surface and reducing myopic, hyperopic, and astigmatic abnormalities that existed prior to such laser surgery.

The above-mentioned related application also deals with engraving intrusion of substrates, 19
Application No. 4 filed by the inventor on March 13, 1987
No. 9,333 and my Application No. 59,617, filed on June 8, 1987, describe the use of corneal manipulative and other procedures in conjunction with sculptural procedures such as the above-mentioned related applications. handle.

The present application deals essentially with engravings and is concerned with the above-mentioned Application No. 49.
It will be appreciated that the manual, preliminary, and other operations of No. 333 and No. 59.617 were immediately filed in connection with the engraving methods and means described herein.

The engraving technique of patent application Ser. It provides corneal irradiation.

[Problem to be solved by the invention]

Although various means have been mentioned to achieve this result, the most convenient and previously mentioned means are those in which an area of spot size is predetermined to achieve a given contour change. requires microprocessor means to ensure a given irradiation program within a course that varies accordingly.

It is an object of the present invention to provide methods and means for adjustable spot size laser engraving of the anterior surface of the cornea in order to achieve the required optical improvement of the eye.

A particular aim is to achieve this with a simple technique that does not require microprocessor control for changing the spot size.

Another special purpose is to achieve the above objective by providing ophthalmic surgery with a stock of differently pre-characterized disposable elements selected from the stock according to the optical changes to be achieved. For example, the surgeon may choose, for example, among the diopter-related changes:
Select for plus or minus spherical changes and/or plus or minus cylindrical changes, which changes the surgeon believes are needed to improve the optical performance of a given eye. It is.

[Means to solve the problem]

The present invention achieves the above objectives by providing an inventory of disposable elements adapted for selective placement into a bath of laser beam irradiation of the cornea. Each of the disposable elements has a membrane that is impermeable to the laser beam and is selectively subjected to removal when irradiated with the laser beam, the thickness of the membrane being such that a given course of irradiation with the laser beam is a pre-characterized function of the local area such that it would require a larger or smaller time to locally remove the laser beam through the membrane and the corresponding local area at the cornea. Allows for targeted elimination collisions. In other words, the changing spot size on the cornea is achieved by the time release function of the membrane, with predetermined area control designed to achieve a diopter change specifically matched to each specifically selectable element. .

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the present invention is disclosed in Patent Section 4.665°913
The eye-holding device 10 described in the patent application is shown in FIG. The device 10 is therefore a hollow ring around a focal axis of contoured air-permeable material to fixate and hold the eye via the palmar-corneal region. end wall 1
Has 1. A side-to-bottom connection 12 to the vacuum pump enables the retention of the wall 11 in engagement with the cornea 14 to be operated on, and optically the device 10 is connected to a fixed connection (by means not shown) to the laser device. It is attached to.

Preferably and suitably, the laser device is an excimer laser, with pulsed ultraviolet radiation below 200 nanometers, such as, for example, provided at 193 nm by an argon-fluoride laser. Preferably, also
The output beam of the laser is a directional projection of a homogeneous coherent beam of circular cross section (e.g. 5 or 6 mm diameter) centered on the optical axis of the eye for shaping and homogeneity of flow distribution. processed for. A means for processing the output of an excimer laser to produce such a homogeneous beam of circular cross section is disclosed in Telf'air et al. Application No. 9, filed February 2, 1987. No. 724 describes this in detail.

Accordingly, there is no need for further detailed explanation here and is identified by appropriate legend in FIG.

According to the invention, a removable membrane 16 with a suitably pre-characterized thickness distribution can be selectively placed in the path of the laser beam projection of the shaft 15.

Conveniently, the membrane 16 is cornered onto the top surface of a planar-parallel holding substrate 17 of material through which the laser beam passes. A suitable material for this substrate is synthetic fused silica (
For example, fluorinated compounds such as 5uprasll, a product of Hcracus-Asarsll, calcium fluoride, magnesium fluoride, barium fluoride. In the form shown, the base plate 17 is housed in the inner annular flange 18 of the ring member 19, adapted via a dependent flange 20 to concentrically engage the circular upper edge of the eye-holding device 10. There is.

Membrane 16 is preferably (but not necessarily) removable under the action of a laser beam at a rate corresponding to the rate of laser beam ablation penetration into the stroma of the cornea. In other words, within the central circular region of laser surgery on the cornea, the maximum thickness of membrane 16 that can be removed is the total maximum thickness of the exposed membrane due to the maximum extent of stromal penetration associated with a particular correction procedure. When the tumor is observed to be ablatively removed, the surgical irradiation can be completed. Suitable materials for removable membrane 16 include polyimide, mylar, and poly(ethene teresitate).

FIG. 2 provides a longitudinal cross-sectional thickness diagram for each of the two selectively removable elements, each of which is shaped for myopia reduction effect. For example, a small maximum thickness T
The contour 21 of 1 appears to decrease from its maximum to zero in the case of a laser beam cross-sectional diameter of s 5 mm, like a function of decreasing radius around the central axis. The contour 22 of large maximum thickness T2 then also appears to decrease from its maximum to zero, like a function of decreasing radius around the central axis. The basic difference in effect between the two contours is that when the membrane 16 is characterized by contour 22 it is much more pronounced due to the 5 mm circular hole than when membrane 16 is characterized by contour 21. This means that it takes a lot of time to reduce the 16 deeply related central circular regions. This fact indicates that the thickness contour T
1 than for a membrane 16 of thickness profile T2.
In other words, achieving a large diopter reduction in corneal curvature. In both cases, the membrane 16 to be removed
The laser beam irradiation has to be terminated when it is observed that the cylindrical hole has achieved an optically used curvature correction of 5 mm diameter, which in this example is 2.5 mm.

In FIG. 3, the newly achieved curvature correction is shown on the cornea 14.
is indicated by the dotted line 23 in relation to the myopic original contour 24 of .

The thickness contours 25-26 shown for membrane 16 in FIG. 4 demonstrate that (a) a small maximum thickness T1 is used to achieve a low degree of hyperopic reduction, and (b) a large maximum thickness T2 is used. It is possible to achieve a high degree of hyperopic reduction using a maximum membrane (16
) indicates the required thickness. In the case of a small thickness profile 25, the thickness is maximum (T1) in the middle and at the outer limits of the optical correction (e.g. 2
．． 5 mm radius), is a function of the radius decreasing to the point of zero thickness; in the case of a large thickness profile 25, the thickness is also a maximum in the center (T1), and the optical correction At the outer limit of , it is a function of radius that decreases to the point of zero thickness. If both contours 25-26 end at the outer limits of the optical correction, then the resulting sculpting of the cornea 14 is characterized by an abruptly defined outer cylindrical wall, but the next 0 of the radius , 5 to 0.75 mm, e.g. by tapering the film thickness to a maximum radius outward of the outer limit of the optical correction, the sharp edges of such walls can be substantially eliminated. can be reduced. Therefore, the supracorneal ablation produces a hyperopic reduction contour 27 (FIG. 5) from the illustrated outer limit of the optical correction, with a gradual chamfer of relatively smooth transition to the remaining outer unexposed area of the cornea. This results in a ring 27'. It has been found that this results in a "tweaked" hyperopia reduction result as described in connection with FIGS. 4 and 5, with a slightly larger radius ( For example, 6.5 to 7mm)
Although it is necessary to adjust the circular cross-section of the laser beam, such cross-sectional area selection is within the capabilities of the apparatus described in the above-mentioned Chilfer et al. Application No. 9,724.

In Figures 2-3 and 4-5, the removable membrane techniques described for the spherical correcting condition are, respectively,
Achieving the cylindrical correction required for astigmatism reduction may also be applicable. For example, if the cylindrical axis of astigmatism correction is perpendicular to and through axis 15 of FIG. 2, then FIG. If taken to represent a longitudinal cross-sectional profile, such as a generally V-shaped flute profile extending along a straight line of diameter about 19, the described course of irradiation will achieve a cylindrical reduction in corneal curvature.

If the annulus 19 is preset in rotation about an axis in which the cylindrical radiation is oriented to coincide with the diagnosed direction of the patient's astigmatism, then the astigmatism is characterized in thickness. By simply correct selection of the maximum thickness of the removable membrane 16, it can be reduced to a defined diopter reduction range. In FIG. 1, arrow 28 on ring 19 is directed by ring rotation relative to azimuth scale 29 on device 10, allowing accurate setting of orientation for astigmatism reduction procedures.

In the embodiment already described, the thickness characterized Wk16 is designed to achieve a varying spot size of the substrate ablation radiation, so that it directs the required radiation through the substrate. Let it pass. And in this state, it is particularly convenient for embodying the substrate and its removable membrane in a circular annulus centered at zero with respect to the optical dimensions of the eye. However, the required transparent substrate material proves to be relatively expensive.

The fragmentary view of FIG. 1A shows that the cost of the substrate may not be an issue as an alternative to using a T-plane mirror 30 as the substrate to carry the removable membrane 16' of characterized thickness. It shows that there is no. In FIG. 1, vt30 is a portion of annular element 31 that is insertably placed within a circular aperture in a support frame structure 32, which is an appendage fixed to the laser housing. The speculum 30 bends it for downward surgical firing perpendicular to the cornea 14;
It is shown tilted at 45° to the incident laser beam to result in a progressively varying spot size range determined by the removal of membrane 16' within a given surgical course. Before incidence on the membrane-coated surface of element 31, the laser beam also
It is to be understood that the flow density is homogeneously distributed along its circular cross-section, with a diameter of 6 mm. However, on the film-coated surface of element 31, the area of incidence is an ellipse with a horizontal minor axis, and the thickness profile in the minor axis is as shown in Fig. 2 for a minor axis width of 5 mm. It should be understood that the width shown in FIG. 2 is as shown in FIG. On the other hand, the width of the long axis is large, as shown in FIG. 6 as 7.08 mm, and the varying thickness curves 21"-22" are shown in the longitudinal cross-sectional plane of FIG. TI, T2 are shown following contours 21-22 in FIG. 2 on a correspondingly expanded scale. In any case, the elliptical pattern whose film thickness is characterized as a myopic emission in the reflected state in Figure 1A passes from zero thickness at the center of the ellipse to a maximum thickness TI (or T2) at the border of the ellipse. I understand. . Therefore, for a given myopia reduction surgical procedure, the initially reflected beam becomes a central spot of circular cross section, which spot is such that a sufficient circular cross section of the incident laser beam is reflected to the surgical incidence on the cornea. The characterized membrane is progressively expanded so that it is removed progressively until, at this point, the surgical procedure has completed the myopia reduction defined on the anterior surface of the cornea.

In the operation of a reflective system (as shown in FIG. 1A), it is important that the elliptical thickness pattern of the removable membrane 16' is orthogonally oriented so that the minor axis is horizontal, and that the adjustment slots and The interlocking is shown schematically at 35 between a point on ring 31 and a reference point on structure 32.

What has been said about myopia reduction by the removal of the membrane 16' previously characterized in the short and long axis cross-sectional planes according to FIGS. 2 and 6, respectively, also shows that the membrane 16' is shown in FIG. The same is true for hyperopic reduction when previously characterized in the short axis and long sleeve cross-sectional planes according to FIG. However, the following is clear from the above discussion. A laser beam with a slightly larger circular cross section is desired for hyperopia reduction surgery, as is clear from FIG.
It is of course possible that the last engraving of ' is possible for the reflex surgery of variable pot size irradiation (FIG. 1A) as well as for the transmission surgery of FIG. 1.

It is found that the described invention achieves all stated objectives and provides an easier and more economical method and means of performing laser ablative recurvature of the cornea. The surgeon's inventory of the membrane-coated ring 19 (or 31) is suitable for the deaf pillar, in terms of thickness and terms well understood by all ophthalmological surgeons, i.e., diopter or its fragments, plus or minus spherical shape. Pre-characterized by labeled thickness contours with and without corrective features. Ring 19
is prepared by applying a standardized coating 16 of the substrate 17 to a graded thickness for successive increments of predetermined final substrate to achieve a given diopter change; A layer of varying thickness is "cut" into its pre-characterized thickness profile by laser ablation according to one or more of the techniques described above, e.g. under microprocessor control. ,
No. 891,285, supra, using the apparatus of FIGS. 8/9 or 15/16, respectively, one can have five orthodontic thickness contours 16 of spherical or cylindrical shape in FIG. A plurality of rings 19 are prepared for inventory, and the above-mentioned No. 891.28
By using the device shown in Figure 30 of No. 5, a person can:
A plurality of such rings 19 with membranes 16 having the thickness profile of FIG. 4 are further provided for inventory.

Thickness characterized reflective ring 31 used in FIG. 1A
It should be noted that the manufacture is simple, as is the case in the transmission ring 19 used in FIG. In particular, using the same apparatus of No. 891,285, supra, as described for characterizing the membrane 16 for myopia reduction or hyperopia reduction, Ill. The difference is that when a uniform thick (TI or T2) film 16' is pre-characterized for the same
The incoming homogeneous circular beam must be tilted at 40°. Such an inclination allows automatic generation of the described contours with precise elliptical balance and orientation using the adjustment reference 35.

However, the ring 31 characterized for astigmatism correction
In using the reflection system of FIG. 1A to produce
It is necessary to provide a series of pre-characterized rings for astigmatism correction.

For the purpose of such manufacture, the above-mentioned No. 891°285
The astigmatism reduction device of FIGS. 15/16 of the above issue is selectively adjustable for alignment and includes a series of such rings 31.
It is well suited for preparing.

The expression "zero thickness" used here to describe one of the limits of the pre-characterized thickness profile of the membrane 16 (or 16') (along with the expression "maximum thickness") ) should be understood as a convenient starting point, the range of thickness variation entails a prior characterization to achieve a given curvature contour of the cornea. Therefore, for some purposes, the true zero thickness can be It is more convenient and desirable to avoid, e.g. to allow the surgeon to perform a test of a given membrane 16 (or 16') before use, e.g. as a corneal sculpture. This is the case when providing for adding a uniformly distributed thickness of the membrane 16 (or 16'') below the defined contour. Test irradiation of a homogeneous beam onto a membrane so characterized allows the surgeon, with his stopwatch, to measure the time required to spread the removal dissolution in uniform increments. It is illustratively possible to make the decision,
Such time is observed visually by determining the appearance of the initial laser beam in the range of the minimum thickness of the film. When the surgeon determines this time, he actually measures his inserted membrane against that rate of infiltration and removal of membrane material, and therefore the surgeon determines the value of the corrective diopter change that he has prescribed. The membrane with element 19 (
or 31), or the surgeon establishes whether to select annulus 19 (or 31) with membranes designed in their progressively larger or smaller diopter variation properties.
Establish whether the prescription should be achieved by selecting 1). Alternatively, the element 19 (or 31) with M16 (or 16-) characterized by a known uniform thickness is the measuring device forming part of the surgeon's inventory;
The timing of the laser's ability to ablate through a single membrane thickness of such elements allows the surgeon to directly determine the current ablation efficiency of the laser beam, thus allowing for example small maximum thicknesses. Characterized membrane 16 with a thickness designed for laser diopter variation characteristics of
By selecting the element 19 (31) with (16-) ill for a given engraving procedure, it is possible to make an appropriate discount for the reduction in removal efficiency.

〔Effect of the invention〕

As can be seen from the above description, the present invention allows laser engraving of the anterior surface of the cornea with an adjustable spot size without the need for microprocessor control to vary the spot size. There is also the advantage that ophthalmic surgery can be carried out by selecting pre-characterized disposable elements from stock according to the optical changes to be achieved.

[Brief explanation of the drawing]

Figure 1 shows a diagram for use in laser surgery on a given cornea.
1A is a fragmentary sectional view showing a variant; FIG. 2 is a differently enlarged Figure 3 is a graphical diagram showing the contours of the film thickness that can be removed to achieve the myopia reduction result in the situation of Figure 1, on an expanded abscissa and ordinate scale; Simplified cross-sectional views illustrating myopia-reducing sculptural surface correction achieved with a removable membrane characterized as follows, FIGS. 4 and 5.
The figures correspond to FIGS. 2 and 3 and illustrate the correction of a hyperopia-reducing sculptural surface achieved with a removable membrane characterized as in FIG. 2; FIGS. FIG. 3 is a diagram corresponding to FIGS. 2 and 3 and showing the relationship of a modification of FIG. 1A; 10...Eye-holding device, 11...End wall of intensive axial concavity, 12...Lateral-boat connection, 14...Cornea, 15...Optical axis, 16.16 '... Removable film, 17... Plane-parallel holding substrate, 18... Inner annular flange, 19... Ring member, 20... Dependent flange, 21° 21-. 22.21-... Contour, 23...
Dotted line, 24...myopic original contour, 25.26...
・Thickness contour, 27... Contour of hyperopia reduction, 27'...
Gently chamfered ring (slope), 28...arrow, 2
9... Azimuth scale, 30... Plane mirror, 31... Ring element, 32... Support frame structure, 35... Adjustment slot and screw engagement. Methods of changing the optical properties of the eye, articles of manufacture used therein, methods of producing the articles of manufacture, and names of the articles of manufacture Francis A. Junior L'Esperance. 4゜Agent 〒105 Address 1-4-10 Nishi-Shinbashi, Minato-ku, Tokyo 5゜Date of amendment order March 13, 1999 (Despatch IJ, 28) 6゜Power of attorney subject to amendment and translated drawings ( Purpose) 7゜Contents of amendment Engraving of the drawings as per the power of attorney and translation attachment (no change in contents)

Claims (36)

[Claims] 1. A method of changing the optical properties of the eye by operating only on the anterior surface of the cornea of the eye, which is impermeable to ultraviolet radiation and has a thickness limit of zero in one local area and maximum in the other local area. selecting a removable membrane with a pre-characterized thickness varying between the limits of and selectively applying ultraviolet radiation to the anterior surface of the cornea by radiation through the membrane;
The maximum thickness of the membrane above ensures volumetric removal of corneal tissue, such that maximum ultraviolet radiation for its sufficient resolution, at the depth of penetration into the stroma, on the contour of a predetermined curvature. A method of changing the optical properties of the eye that is sufficient to require irradiation. 2. 2. The method of claim 1, wherein the ultraviolet radiation is a coherent beam of generally circular cross section corresponding to at least the area of the cornea such that the optical change is obtained. 3. 3. The method of claim 2, wherein the cross-section of the beam is characterized by a substantially uniform flow density distribution. 4. 2. The method of claim 1, wherein the irradiation follows the point of substantially complete removable photolysis of the region of maximum thickness of the removable film. 5. The method of claim 1, wherein the removable membrane is a material selected from the group consisting of polyimide, mylar, and poly(terephthalate). 6. 2. The method of claim 1, wherein the ultraviolet radiation is pulsed excimer laser radiation. 7. 2. The method of claim 1, wherein the selected removable film is coated on a substrate that is transparent to ultraviolet radiation. 8. 2. The method of claim 1, wherein the selected removable film is coated on a substrate that is a reflector of ultraviolet radiation. 9. The pre-characterized thickness (Tm) of the membrane is substantially equal to the desired maximum easy-to-remove penetration depth of the substrate and is given by the formula Am/
times As, where, for a given intensity of laser beam intensity, Am is the membrane depth-penetration removal ratio;
2. The method of claim 1, wherein As is the substrate depth-to-penetration removal ratio. 10. An article of manufacture of a removable membrane for consumable use to provide a predetermined, easy-to-remove engraving of an optically used central region of the anterior surface of the cornea, the membrane comprising: An article of manufacture having a central region of varying thickness ranging from zero thickness at the center to a maximum thickness at predetermined outer limits of said central region. 11. A planar parallel plate of substrate material that transmits ultraviolet radiation and is retained by said plate for consumable use to provide a predetermined, easy-to-remove engraving of the optically used central region of the anterior surface of the cornea. an article of manufacture having a removable membrane layer impermeable to ultraviolet radiation and having a thickness varying as a function of radius between a predetermined center inner and radial outer limits of the central region; It has a central circular area of
The thickness extends from zero on one side of said limits to a maximum on the other side of said limits, said membrane being predetermined to achieve a total removal of said maximum thickness for a given intensity of ultraviolet radiation. such that the anterior surface of the cornea is exposed to ultraviolet radiation by transmission through the plate, such that the predetermined total exposure is such that the anterior surface of the cornea is exposed to ultraviolet radiation by transmission through the plate; The manufactured product is predetermined to achieve a given maximum substrate-penetration depth for a given new curvature of the engraving. 12. a substrate with a flat surface that is a reflector of ultraviolet radiation and by means of said surface for consumable use such as to provide a predetermined, easy-to-remove engraving of the optically used central region of the anterior surface of the cornea; An article of manufacture having a removable membrane layer supported thereon, said membrane being impermeable to ultraviolet radiation and having a central thickness varying as a function of radius between the central inner and radial outer limits of the elliptical area. having an elliptical area, the thickness extending from zero at one of said limits to a maximum at the other of said limits, said membrane achieving an overall removal of said maximum thickness for a given intensity of ultraviolet radiation. such that it requires a predetermined total irradiation to be of such maximum thickness within said elliptical area, and said predetermined total irradiation is subjected to ultraviolet radiation by reflection from said surface. A product of manufacture that is predetermined to achieve a given maximum stromal-penetration depth for a given new curvature of engraving of the anterior surface of the cornea. 13. 13. Article of manufacture according to claim 11 or 12, wherein the thickness change is an increasing function of radius between said limits, thereby achieving a new curvature of the myopic reduction cornea. 14. 13. Article of manufacture according to claim 11 or 12, wherein the thickness change is a decreasing function of radius between said limits, thereby achieving a new curvature of the hyperopic reduced cornea. 15. 12. The article of manufacture of claim 11, wherein the substrate and membrane are assembled to a peripheral annular support frame, and the circular region is coaxial to the frame. 16. 13. The article of manufacture of claim 12, wherein the substrate and membrane are assembled into an annular support frame and occupy an angular locking structure in at least one area of the periphery of the frame. 17. The thickness change is a decreasing function of the radius between the above limits, thereby achieving a new curvature of the hyperopic reduced cornea,
13. An article of manufacture as claimed in claim 11 or 12, in which an annular ring of radially varying thickness continues around the circumference of the region. 18. 12. A method of manufacturing an article of manufacture according to claim 11, comprising providing the plate with a uniform thickness film layer on one planar surface thereof and exposing a central region thereof to selective ultraviolet radiation;
The removal of a volume of membrane material is accompanied by a removable photodegradation at one location within said central region with a full depth penetration and at the other location within said central region with substantially zero depth penetration, so that A manufacturing method in which a defined thickness profile is provided between said locations. 19. Plano-parallel plates of substrate material that allow ultraviolet radiation to pass through and said plates for consumable use to provide a predetermined, easy-to-remove astigmatism-reducing engraving of the optically used central region of the anterior surface of the cornea. an article of manufacture with a removable membrane layer retained by the membrane, said membrane being impermeable to ultraviolet radiation and having an increasing function transversely offset from a geometric axis extending diametrically through the center of the central region; having a central circular region of varying thickness, the thickness extending equally maximally from zero along an axis extending in the direction of said diameter, and limiting laterally oppositely from the axis extending in the direction of said diameter; , the membrane is such that, for a given intensity of UV radiation, a predetermined total irradiation is required in order to achieve a total removal of the maximum thickness. The maximum thickness and said predetermined total irradiance is the maximum substrate given for a given sculptural astigmatic reduction new curvature of the anterior surface of the cornea exposed to ultraviolet radiation due to transmission through said plate. A manufactured product that is predetermined to achieve a penetration depth. 20. A substrate with a flat surface that is a reflector of ultraviolet radiation and a predetermined astigmatism reduction of the optically used central region of the anterior surface of the cornea, described above for consumable use such as providing an easy-to-remove engraving. An article of manufacture with a removable membrane layer supported by a surface, said membrane being impermeable to ultraviolet radiation and transverse to a geometric axis extending diametrically through the intersection of the major and minor axes of the elliptical region. with a central elliptical region of thickness varying in an increasing function from zero along an axis extending in the direction of said diameter, and with a maximum in extreme limits equal and opposite from the axis extending in the direction of said diameter. spread out, said membrane is spread within said elliptical area such that, for a given intensity of UV radiation, a predetermined total irradiation is required to achieve a total removal of said maximum thickness. such that the predetermined total irradiance is a given maximum stromal-invasion for a given new curvature of the engraving of the anterior surface of the cornea exposed to ultraviolet radiation by reflection from the surface. Manufactured products that are predetermined to achieve depth. 21. In an inventory collection or kit having a plurality of articles of manufacture according to claim 11 or 12 or 19 or 20, the plurality of articles of manufacture include at least one article of manufacture having a first and a removable membrane of a small maximum thickness. and a second article of manufacture having a removable membrane of a second and greater maximum thickness. 22. In an inventory collection or kit with a plurality of articles of manufacture according to claim 11 or 12 or 19 or 20, the plurality of articles of manufacture comprises at least one article of manufacture according to one of the preceding claims; an inventory collection or kit having at least another article of manufacture according to another. 23. 13. A method of manufacturing an article of manufacture according to claim 12, wherein the reflector is provided with a film layer of uniform thickness on the flat surface, and the central region thereof is oriented at an acute angle of incidence. Exposure to selective ultraviolet radiation causes removable photolysis of the removal of a volume of membrane material, essentially at a full depth penetration at one location within the central region and at another location within the central region. A manufacturing method with zero depth penetration, whereby a predetermined thickness profile is provided between said locations. 24. 18 or 2, wherein the ultraviolet radiation is characterized by a beam which is circularly symmetrical about a central axis of incidence on said membrane layer.
The method described in 3. 25. In an inventory collection or kit having a plurality of articles of manufacture according to claim 11 or 12 or 19 or 20, the plurality of articles of manufacture include removable membranes of similar varying thickness with different maximum thicknesses. In at least another such article of manufacture, the film layer is of a predetermined uniform thickness, whereby first exposing the uniform thickness film to a source of ultraviolet radiation to remove the predetermined Note that the totality of such irradiation is required to be resolved into a full range of uniform thickness, and the current removal efficacy of the above source can be examined, thereby allowing the desired corneal Selecting for corneal engraving one of the above-mentioned articles of manufacture that can best achieve the curvature change; an inventory collection or kit providing appropriate tolerances for such efficacy. 26. A method of changing the optical properties of the eye by operating only on the anterior surface of the cornea of the eye, which is impermeable to ultraviolet radiation and has a minimum thickness limit in one local area and a maximum thickness in the other local area. Selecting a removable film with a pre-characterized thickness varying between the limits of Radiation impingement on the membrane selectively directs UV radiation to the anterior surface of the cornea, with the result that the incident UV radiation begins to pass into the cornea through a local area of zero thickness, and the maximum of the membrane The thickness requires maximum ultraviolet radiation irradiation such that for its full dissolution, with a depth of penetration into the stroma and a contour of predetermined curvature, ensuring volumetric removal of corneal tissue. A method of changing the optical properties of the eye that is sufficient to. 27. The pre-characterized maximum thickness of the membrane (Tm), the minimum thickness of the membrane (To) is substantially equal to the desired maximum penetration depth amenable to removal of the substrate, which is twice the formula Am/As; 27. The method according to claim 26, where, for a given intensity of laser beam intensity, Am is the membrane depth-to-penetration removal ratio and As is the substrate depth-to-penetration removal ratio. Method. 28. 2. The one local region is an outer circumference of maximum radius corresponding to the maximum radius of the central circular region of optical change curvature of the cornea, and the other local region is the center of the outer circumference. or the method described in 26. 29. The other local area is an outer circumference with a maximum radius corresponding to the maximum radius of the central circular area of optical change curvature of the cornea, and the one local area is the width center of the outer circumference. 27. The method according to 1 or 26. 30. said one local area is a straight line in diameter, said straight line extending along the outer circumference corresponding to the central circular area of optical variation curvature of the cornea, said straight line being oriented according to the state of astigmatism to be corrected; 2. The other local regions are similar but mirror image regions within said outer circumference, equal at most and oppositely offset from said straight line of diameter.
6. The method described in 6. 31. The elapsed radiation exposure time is timed to reach a minimum thickness radiation of zero prior to the actual laser action on the cornea, and generally the emitted laser radiation is timed to achieve a predetermined curvature profile. 27. The method of claim 26, wherein the method is within a predetermined tolerance range. 32. In a method of changing the optical properties of the eye by operating only on the anterior surface of the cornea of the eye, it is impermeable to radiation from a special tissue ablation laser and has a zero thickness limit in one localized area. Special tissue ablation laser radiation to the anterior surface of the cornea by selecting a removable membrane with a pre-characterized thickness varying between maximum limits in other localized areas and emitting through said membrane. selectively apply the membrane to a contour of predetermined curvature, at a depth of penetration into the stroma, such that the maximum thickness of the membrane ensures volumetric removal of the corneal tissue, and for its sufficient resolution. A method of changing the optical properties of the eye that is sufficient to require maximum irradiation such as: 33. In a method of changing the optical properties of the eye by operating only on the anterior surface of the cornea of the eye, it is impermeable to radiation from special tissue ablation lasers and has minimal thickness limits in one localized area. Selecting a removable membrane with a pre-characterized thickness varying between a maximum limit in other localized regions, such as with reducing said minimum thickness to zero The radiation impingement on the membrane for radiation irradiation selectively directs the special tissue ablation laser radiation to the anterior surface of the cornea, with the result that the incident tissue ablation laser radiation penetrates the cornea through a local area of zero thickness. At the depth of penetration into the stroma, the maximum thickness of the membrane above ensures a volumetric removal of the corneal tissue, and for its sufficient dissolution into a contour of predetermined curvature. How to change the optical properties of the eye is sufficient to require such maximum laser radiation irradiation. 34. Claim 32 or 3, wherein the radiation is pulsed laser radiation.
The method described in 3. 35. 3. The selected removable membrane is coated on a substrate that is transparent to specialized tissue ablation radiation.
2 or 33. 36. 34. The method of claim 32 or 33, wherein the selected removable film is coated on a substrate that is a reflector of specialized tissue ablation radiation.