WO2001024746A1

WO2001024746A1 - Device and method for carrying out thermocoagulation

Info

Publication number: WO2001024746A1
Application number: PCT/DE2000/003510
Authority: WO
Inventors: Benedikt Jean; Thomas Bende
Original assignee: Benedikt Jean; Thomas Bende
Priority date: 1999-10-05
Filing date: 2000-10-05
Publication date: 2001-04-12
Also published as: DE19947778A1; AU1992501A; DE10082974D2

Abstract

The invention relates to a device and method for carrying out thermokeratoplasty on the eye, comprising means for detachably fixing said device to an eye that is to be treated and at least one holding device for retaining the direction-indicating part of means for bringing a focused beam of light onto the eye. At least one holding device can be automatically moved in at least two independent, non-parallel directions relative to the optical axis of the eye that is to be treated so that the beam of light can be directed to any points of the cornea of the eye that is to be treated. Precision and rapidity in treatment are thus increased for the benefit of the patient.

Description

Device and method for performing thermocoagulation

The invention relates to a method and a device for carrying out a contact thermokeratoplasty on the eye with means for releasably attaching the device directly or indirectly to an eye to be treated and at least one holder for holding the directional part of means for applying the bundled Beam of light on the eye.

Such methods and devices are known in the form of masks fixed to negative pressure and have proven particularly useful in laser thermokeratoplasty, for example using diode lasers. In the known methods, a fixation mask is fixed by applying negative pressure to the cornea or to the coma-scleral transition area of the eye, whereupon prepared disks with bores for the directional part of a laser device, which serve as templates, are inserted into the fixation mask that a laser beam can be directed into the eye through the bores at predefined locations or a handpiece of a laser can be placed on the eye, which triggers coagulation there. Alternatively, the cornea can also be attached using a ring? or star markers, as disclosed, for example, in WO-Al-95 15134, to which the laser beam is then applied directly. Laser thermokeratoplasty, in which the cornea is changed by introducing rotationally symmetrical coagulation foci of defined geometry and precisely defined depth of coagulation into the cornea, or by dividing the flatter meridian by sectorally applied points at a defined distance from the flat axis, has proven to be an effective and long-term stable procedure proven to correct farsightedness, presbyopia and high astigmatism.

In addition to the methods described in the introduction, in which the directional parts for applying a bundled light beam to the eye are usually placed on the eye by means of a handpiece, so-called non-contact methods are also known, for example from DE 197 52 949 AI, which, however, is described in generally do not allow long-term stable changes to the cornea, since the non-contact methods mainly coagulate in the upper and middle third of the cornea thickness, while scientific studies have shown that the coagulation foci reach between 80 and 100% of the cornea thickness for an effective and long-term stable correction have to.

Although the so-called contact application methods have certain advantages over non-contact methods, their implementation often still presents difficulties in practice. For example, the heat spread can be limited so that the temperature-sensitive endothelium of the cornea is not damaged. The effectiveness of thermokeratoplasty also depends critically on the depth of coagulation. The diameter of the coagulation zones with regard to the individual corneal diameter plays an important role, and the individual corneal thickness, which is typically between about 520 and 700 μm, must also be taken into account. The angle of attachment of the handpiece should be approximately 90 ° to the surface, and the horn skin extension at the place of application should be optimal. All these points have to be considered in the rotationally symmetrical application for hyperopia and press biopy correction as well as in the sectoral application for astigmatism correction. In addition, asymmetrical coagulation patterns on the cornea are required to correct irregular astigmatisms.

Proceeding from this, the object of the invention is to specify a method and a device which allow contact thermokeratoplasty to be carried out particularly precisely, but also quickly.

The object is achieved on the one hand by a device of the type mentioned at the outset, in which the at least one holder can be moved automatically in at least two directions which are not parallel to the optical axis of the eye to be treated in such a way that the light beam strikes any points on the cornea of the person to be treated Eye can be directed.

The device allows a fully or at least largely automated implementation of a contact keratoplasty and has the great advantage that it can also be retrofitted to existing keratoplasty devices. In particular, existing light sources, usually lasers, can be used in addition to the Corresponding directional parts for applying the light rays to the eye can be used further. As a rule, the light from a laser source is directed onto the eye by means of flexible optical fibers, so-called optical fibers. The end of the optical fiber (s) then determines the direction of the light beam emerging from the fiber (s) and can be clamped in the automatically positionable holder or otherwise secured in the holder.

Of course, the device itself can also have means, in particular a laser, preferably a diode laser, for generating the light beam to be directed onto an eye to be treated in thermo-keratoplasty.

Since, as a rule, coagulation has to be carried out at a number of places, often arranged on a circle or ring, the device can advantageously be developed in such a way that, without changing the position of the holder, at least two light beams hitting an eye to be treated at different points at the same time or in succession can be generated. This can be realized in different ways, for example by a beam splitter with two or more beam outputs, or by separate lasers, each with its own light guide.

There are various ways of ensuring that the light beam (s) can be directed to any location on the cornea. For example, it is possible to automatically mount the holder essentially parallel to the main viewing direction of an eye to be treated to make the first axis and a second axis parallel to the first axis movable, the distance between the two axes and the radius of the rotational movement of the holder around the second axis should in each case correspond to approximately half a typical corneal diameter, so that then by appropriate rotations around the first and second axis any point on the corneal surface can be controlled.

However, it has proven to be particularly expedient to design the holder to be rotatable automatically about a first axis which is essentially parallel to the main line of sight of an eye to be treated and to be movable along a translation direction which is essentially perpendicular to the first axis. In particular, the holder can be provided on a rail rotatably mounted about the first axis and can be moved along this rail.

It goes without saying that the ability to move around the first, essentially parallel to the main line of sight of the eye to be treated is also advantageous independently of the other features, since treatment generally requires annularly arranged types of coagulation, so that the necessary displacement of the non-given part quickly and can be guaranteed as error-free as possible.

A further automation and thus elimination of human error sources can advantageously be achieved in that means for moving the directional parts inserted into the holder towards and away from an eye to be treated and / or means for adjusting the angle at which the or the light beam (s) are irradiated on the eye will / will be provided. Means for determining the contact pressure of the part of the means for contacting an eye to be treated for applying a light beam to an eye against the eye are preferably also provided.

In order to ensure that the device can be used as widely as possible for different patient-specific requirements, means for regulating the energy of the incident light rays can be provided. The position of the focal point of the incident light rays can also preferably be adjusted. Depending on the type of light source used, the wavelength of the light rays incident on the eye can even be changeable.

A further automation is possible if means are also provided on the device for measuring the eye topography and / or the internal structure of the eye body. These then allow automatic adjustment of the light rays to be guided to the eye on the basis of data "online" determined about the eye to be treated.

A central evaluation is preferably used to control the device and in particular to automatically set certain positions of the holder relative to an eye to be treated? and control unit, which can also be a multifunctional unit, for example a PC or a workstation, by means of which data about the treatment and the patient being treated can then also be processed and stored. Such data for the documentation of information The keratoplasty performed can be, for example, the positions at which light rays were directed into the eye, the energy radiated per hearth, the exposure time per hearth, the total energy per hearth, the number of hearths per ring, the number of rings and the Diameter of the rings.

In terms of the method, the stated object is achieved by a method for carrying out thermokeratoplasty on the eye, means for applying at least one bundled light beam to an eye to be treated being attached directly or indirectly to the eye, whereupon at least that part of the part which determines the direction of the at least one light beam Means for applying the light beam is automatically moved to different locations of the eye, at which locations the light beam is then applied to the eye.

The method can be carried out in such a way that the eye topography and / or the internal structure of the eye body is at least partially automatically measured before the light beam is applied. The positioning of the part of the means for applying the light beam which determines the direction of the light beam can then advantageously take place on the basis of automatically acquired data about the eye topography and / or the internal structure of the eye body.

In particular, if a laser, for example a diode laser, is used as the light source, the method according to the invention can be carried out such that the energy of the incident light beam, the focal point of the radiated light beam and possibly also the wavelength of the radiated light beam can be changed taking patient-specific data into account in order to achieve an optimal treatment result.

Further details and advantages of the invention result from the following purely exemplary and non-restrictive description of some implementation examples of methods according to the invention and a device according to the invention in connection with the drawing. Show it:

1 shows a device according to the invention with a holder for the directional part of means for applying a light beam to an eye, which can be moved translationally along a rail rotatably mounted about a first axis,

Fig. 2 shows the device of FIG. 1 in side view, it was indicated schematically that the end piece of an optical fiber was inserted into the holder, and

3 shows a control and laser unit for controlling the device shown in FIGS. 1 and 2 and generating laser beams to be directed onto the eye.

1 and 2, a device for carrying out a contact thermokeratoplasty on the eye, designated in its entirety by 10, is shown, the main components of which are a handpiece 12 and an attachment part 14, the attachment part 14 being known per se and not shown here Can be fixed to an eye to be treated, in particular by applying a negative pressure so that the attachment part 14 is sucked onto the eye and remains fixed in a certain position during the execution of the keratoplasty.

An inner ring 16 is rotatably mounted in the attachment part 14, the axis of rotation roughly corresponding to the main line of sight of an eye to be treated and coinciding with the axis of the attachment part 14 which is circular in this exemplary embodiment. The inner ring 16 is rotated about the said axis by means of a bevel gear 18 engaging in a corresponding toothing on the outside of the inner ring 16, the bevel gear 18 being driven by an exactly controllable stepper motor provided in the handpiece 12 in this exemplary embodiment and not shown here is, so that an accurate positioning of the rotational position of the inner ring 16 about the first axis is possible.

A rail 20 provided with micro-toothing in this exemplary embodiment is stretched across the inner ring 16, along which the actual holder 24 for the directional parts 26 of means for applying a bundled light beam to an eye to be treated can be moved by means of a corresponding stepping motor 22. The direction-giving parts of the means for applying a bundled light beam, which are indicated only cut off in FIG. 2, are generally the end of an optical fiber through which a laser beam can be guided. As also indicated in FIG. 2, an intermediate element which can be automatically moved towards and away from an eye can be held in the holder 24. Piece 28 may be provided, which advantageously allows the contact pressure of the parts of the means for applying the bundled light beam coming into contact with the eye to be varied. Means provided for determining this contact pressure are also not shown. In an advantageous embodiment of this embodiment, means for changing the angular position of the light dome with respect to the first axis can also be provided.

The control and laser unit shown in FIG. 3, designated in its entirety by 30, in this exemplary embodiment comprises three assemblies, namely a diode laser 32, a power supply unit 34 for supplying the respective assemblies and the device shown in FIGS. 1 and 2 Power and a control and monitoring unit 36 which contains the actual control electronics and control software and which has various input means 38, 40, 42, 44 for inputting control and control instructions and a control monitor 46 which can be tilted in this exemplary embodiment.

To carry out a contact laser thermokeratoplasty by means of the units shown in FIGS. 1 to 3, which here form a common device and via corresponding data, current, not shown? and signal line means are directly or indirectly coupled to one another, an optical fiber 26 is attached at one end to the laser 32 and at the other end in the holder 24, so that a laser beam generated by the laser 32 through the optical fiber 26 onto an eye to be treated gelei- can be tet. The attachment ring 14 is then fixed to the eye to be treated by applying a negative pressure.

After entering appropriate control instructions either directly on the control unit 36 or e.g. Via a PC (not shown further here) which is coupled to the control unit 36 in a manner known per se, the holder 24 is brought into a position by moving the inner ring 16 and moving the holder along the rail 20, at which coagulation is triggered by the application of a laser beam shall be. There is the end of the optical fiber 26 coming into contact with the eye to be treated or a lens provided at the end of this fiber or a corresponding contact piece by means of the intermediate piece 28 or? if the contact pressure is too high - moved away from it. It should be noted at this point that by appropriately designing the device 10, in particular the holder 24, it is also easily possible to change the angle at which the laser beam is directed onto the eye and to set it in the desired manner.

When the directional parts of the means for applying the laser beam are at the desired location, a laser beam is generated by means of the laser 32 and applied to the eye, whereby coagulation is triggered. The holder 24 is then positioned in the manner described above over the next point at which coagulation is to take place. In a departure from the embodiment shown, it is of course also possible to use several brackets or one bracket for several directional parts. le of means for applying bundled light beams to an eye to be treated, so that coagulation can be triggered simultaneously or successively without moving the holder (s) at several desired locations.

When performing a contact thermokeratoplasty, in which the coagulation foci are arranged on imaginary rings, the number of foci per ring can be varied. Usual numbers are, for example, 8, 10 or 12 herds per ring. The distance between the coagulation points also changes with the number of foci per ring. This can be used both rotationally symmetrically for hyperopia / press biopia and sectorally for astigmatism corrections.

The depth of the foci with a defined geometry depends on the constant angle (typically 90 °) at the respective point on the cornea. The coagulation result can be further optimized by appropriately securely anchoring the direction-giving part of the means for applying the light beam, that is to say generally the end of an optical fiber and constant contact pressure on the cornea.

You can react to different corneal thicknesses by adapting the energy, adapting the focus length or adapting the wavelength (on the laser side). The aim is to achieve optimal, maximum deep coagulation with sufficient volume while optimally protecting the endothelium. The respective positions are recorded and documented for the individual treatment, so that a treatment protocol from energy 13

energy from stove, exposure time per stove and thus total energy per stove, number of stoves per ring, number of rings, diameter of the rings. The data can be correlated, e.g. with the topographically determined result of the operation, and can be combined into an archive of treatment data and clinical results. Numerous such protocols can then be used to determine refined treatment normograms from the sum of the data obtained from many doctors and many patients.

The invention also allows variable control of asymmetrical locations, such as those e.g. for the treatment of irregular astigmatisms of the cornea, variable control is required in order to obtain a spherical or precisely defined toric corneal surface by asymmetrical division after successful execution of the keratoplasty.

The respective control coordinates at which light rays are to be directed onto the eye in order to trigger coagulation can be combined partly from a data memory, partly from the individual patient examination (e.g. diameter of the cornea, corneal thickness etc.) and linked to a treatment program.

An important advantage of the automation of the control of the individual coagulation points according to the invention is the possibility of automatic operation data archiving. The clinical result can later be assigned to this data, so that a database can finally be set up which allows defined starting situations with earlier ones Compare treatment results and the geometries on which they are based in order to receive individual treatment suggestions.

According to the described invention, all the variable sizes still outstanding today for optimizing the laser thermokeratoplasty in the three-dimensional application can be optimized for the respective individual case. Operating points are controlled safely and reproducibly, the coagulation results are optimized geometrically and energy-efficiently and fluctuations in hands-free application are avoided. The reduction of the variable parameters leads to an increase in therapeutic accuracy and thus to a new qualitative dimension of thermokeratoplasty. The introduction of a highly precise, mask-mediated application enables the individual biological range of variation resulting from patient age and other variable sizes to be recorded more precisely and correction criteria for keratoplasty to be derived from this.

It goes without saying that the device described above or the method described can be connected to any measuring devices or measuring methods for determining the eye topography or the internal structure of the eye body. In this way it can be determined at which points and / or to what extent a light beam should be directed onto the eye. In particular, it is possible to form a data pool so that, depending on the measured or determined corneal thickness, corneal structure or the measurements of the inside of the eye, in particular the optically see properties of the inside of the eye, automatically suggested or determined where the light beam is to be used.

Claims

claims

1. Device for performing a thermokeratoplasty on the eye with means for releasably attaching the device to an eye to be treated and at least one holder for holding the directional part of means for applying a bundled light beam to the eye, characterized in that the at least one holder in at least two directions that are not parallel to the optical axis of the eye to be treated can be automatically moved in such a way that the light beam can be directed to any points on the cornea of the eye to be treated.

2. Device according to claim 1, characterized in that means, in particular a laser, preferably a diode laser, are provided for generating the light beam to be directed onto an eye to be treated in thermokeratoplasty.

3. Device according to claim 2, characterized in that the device is designed such that at least two light beams striking an eye to be treated can be generated simultaneously or in succession without changing the position of the holder.

4. Device according to one of claims 1 to 3, characterized in that the holder automatically by one to the main gaze device of an eye to be treated essentially parallel first axis can be moved.

5. The device according to claim 4, characterized in that the holder can be moved about a second axis parallel to the first axis, the distance between the two axes and the radius of the rotary movement of the holder about the second axis each corresponding to approximately half a typical corneal diameter.

6. The device according to claim 4, characterized in that the holder can be moved in a translation direction substantially perpendicular to the first axis.

7. The device according to claim 6, characterized in that the holder is provided on a rail rotatably mounted about the first axis and can be moved along this rail.

8. Device according to one of claims 1 to 7, characterized in that means are provided for moving the directional parts inserted into the holder towards and away from an eye to be treated.

9. Device according to one of claims 1 to 8, characterized in that means for determining the contact pressure of the part of the means which comes into contact with an eye to be treated

Applying a light beam to an eye against the eye are provided.

10. Device according to one of claims 1 to 9, characterized in that means are provided for automatically determining the angle at which the light beam (s) is / are irradiated onto the eye.

11. The device according to one of claims 1 to 10, characterized in that means are provided for adjusting the angle at which the light beam (s) is / are irradiated onto the eye.

12. Device according to one of claims 1 to 1 1, characterized in that means for adjusting the energy of the irradiated

Light rays are provided.

13. Device according to one of claims 1 to 12, characterized in that means are provided for adjusting the position of the focal point of the incident light rays.

14. Device according to one of claims 1 to 13, characterized in that means are provided for adjusting the wavelength of the light rays irradiated on the eye.

15. Device according to one of claims 1 to 14, characterized in that means are provided for measuring the eye topography and / or the inner structure of the eye body.

16. Device according to one of claims 1 to 15, characterized in that a central evaluation? and control unit is provided for automatically adjusting certain positions of the holder relative to an eye to be treated.

17. Device according to one of claims 1 to 16, characterized in that means for documenting information about the keratoplasty performed, in particular a data memory for storing the position (s) at which light rays were directed into the eye, and / or the pro Stove radiated energy and / or the exposure time per stove and / or the total energy per stove and / or the number of stoves per ring and / or the number of rings and / or the diameter of the rings are provided.

18. A method for carrying out thermokeratoplasty on the eye, wherein means for applying at least one bundled light beam to an eye to be treated are directly or indirectly attached to the eye, characterized in that at least the part of the means determining the direction of the at least one light beam to apply the light beam is automatically moved to different places on the eye, at which points the light beam is then applied to the eye.

19. The method according to claim 18, characterized in that before the application of the light beam, the eye topography and / or the inner Structure of the eye body is at least partially automatically measured.

20. The method according to claim 19, characterized in that the positioning of the part of the means for applying the light beam which determines the direction of the light beam on the basis of automatically detected

Data about the eye topography and / or the internal structure of the eye body is made.

21. The method according to any one of claims 18 to 20, characterized in that the angle of incidence at which the light beam is directed to the eye is automatically set to a predetermined target value.

22. The method according to any one of claims 18 to 21, characterized in that the energy of the incident light beam is changed taking into account patient-specific data.

23. The method according to any one of claims 18 to 22, characterized in that the focus point of the incident light beam is changed taking into account patient-specific data.

24. The method according to any one of claims 18 to 23, characterized in that the wavelength of the incident light beam is changed taking into account patient-specific data.

5. The method according to any one of claims 18 to 24, characterized in that information about the keratoplasty is automatically stored during or after the keratoplasty, in particular information about the position (s) at which light rays were directed into the eye and / or energy radiated per hearth and / or the exposure time per hearth and / or the total energy per hearth and / or the number of cookers per ring and / or the number of rings and / or the diameter of the rings.