DE19943735B4 - Device for irradiating the eye - Google Patents

Abstract

contraption for irradiating the eye for correcting vision defects a light source (10), the treatment radiation (11) emits with wavelength in the long-wave UV-A region above the corneal absorption and / or in the visible and / or near-infrared spectral range, which in the eye lens (77) is absorbed and locally irreversible changes of the lens substance generates, means for temporal modulation (12) and intensity regulation the treatment radiation (11), spatial modulation means (20) Treatment radiation (11), an optical system (30) with at least one optical Axis for introducing the modulated treatment radiation (11) in predetermined areas of the eye lens, means (71) for determining the orientation of the eye lens axis and means (72) for fixation of the eye and / or eye-tracking.

Description

The The invention relates to a device for irradiating the eye for the purpose of Correction of vision defects and is in ophthalmology, refractive surgery or laser medicine can be used.

In order to we need to be able to see our environment properly, the optical picture must our environment to the receptors of the retina done faultlessly. The surface curvatures and refractive index transitions in the eye have to to the spatial Fit arrangement of receptors in the retina.

is the faultless optical image disturbed, so the defect on corrected in the traditional way with glasses. A curved glass with certain refractive index, thickness and curvature ratios is defined in Distance in front of the eye.

It It is also known that comparatively thin lenses, called "contact lenses", are immediately on the cornea of the eye are put on.

Except these Corrections by superior optics, there is the possibility operational changes on the eye itself.

In The corneal surgery is going through either the thickness of the cornea Ablation or curvature the cornea changed by incision (keratotomy). As well is the plastic deformation of the cornea by thermal action (Thermokeratoplasty) possible.

by virtue of their situation "on furthest ahead "is the Cornea is very accessible to surgical treatment and therefore seems so too to be most intensively researched.

The Laser corneal surgery is described in a variety of documents usually as a laser ablation, mainly with excimer lasers, in different cases as a thermal shrinkage of the cornea, with a change the curvature of the optical interface.

An apparatus of ophthalmic surgery is in US 4,718,418 in which a scanned UV laser is used for the controlled ablative photodekomposition of selected corneal areas. The radiation density and exposure time are controlled to achieve a desired ablation depth, the scan motions are coordinated to achieve a desired surface change, as a result of which the cornea becomes a corrective lens.

The possibilities of erosion of surfaces with a laser apparatus comprising means for selecting and controlling the profile and dimensions of the irradiated area by each pulse of the laser energy without varying the energy density of the beam, by varying the dimensions of the irradiated area between the pulses, be in US 4,941,093 explained.

In US 5,334,190 U.S. Patent No. 5,876,830 describes methods and apparatus for correcting optical defects in vision that use an infrared radiation source and a focusing element to alter the curvature of the eye by introducing focused infrared radiation in a controlled manner into the corneal stratum tissue. Heat-induced shrinkage of the corneal stratum tissue changes the corneal curvature US 5,423,801 discloses a method and arrangement including a laser and a beam-forming mask that reshapes the Bowman's membrane without substantially penetrating the stroma of the eye.

Various possibilities of intensity variation of the corneal eroding radiation by means of erodible masks predefined erosion resistance or graded intensity filter, by means of selectively varying openings or other mechanisms of selectively exposed areas US 5,505,723 explained.

In US 5,520,679 A refractive laser surgery method is described which utilizes a compact, low cost laser system having a computerized scanner with a non-contact unit for both photo-ablation and photocoagulation. The basic system can be flash lamps, diode-pumped UV solid-state lasers (193-215 nm), compact excimer lasers (193 nm), free-running Er: glass (1.54 μm), Ho: YAG (2.1 μm), Q-switched Er: YAG ( 2.94 μm), tunable IR lasers (750-1100 nm) and (2.5-3.2 μm). Advantages of the contactless scanner include compactness, higher precision, lower cost, and greater flexibility. Starting from beam overlap, ablation rate and coagulation patterns, lasers are selected that realize energies of 10 μm to 10 mJ, with repetition rates of 1 to 10,000, with pulse lengths of 0.01 nanoseconds to a few hundred microseconds and spot sizes of 0.05 to 2 mm for use in refractive laser surgery.

Corneal profiling by means of a ring beam of ablative radiation to correct refractive vision defects is described in US Pat US 5,613,965 Shown methods of laser ablation and the associated devices are shown in FIG US 5,624,436 and US 5,637,109 or in DE 19752949 described, containing a laser beam, which is required to process the object in a certain form, the optical system, which is necessary to bring the laser beam to the object to be processed, a diaphragm, which changes the ablation region, a control device for the diaphragm movement and a guide device, which leads the control device for forming a curved surface with a specific optical characteristic. Thus, intensity profiles of excimer laser radiation for corneal ablation can be improved.

The possibility of modifying the intensity distribution of light beams, as well as laser beams for the purpose of erosion of surfaces with predetermined profiles by means of a rotating mask, consisting of one or more openings, in US 5,651,784 shown.

Laser surgery apparatus and methods using pulsed UV excimer lasers at 193 nm with energy densities greater than 20 mJ per cm ² and repetition rates of up to 25 pulses per second to transmit their radiation through a mask to the corneal tissue to perform ablation of given shape and depth by a process of ablative photodecomposition therein US 5,711,762 and US 5,735,843 described.

One way of combining contiguous spherical and cylindrical corrections on the corneal surface by means of a variable iris diaphragm and a movable gap to reduce myopia and astigmatism is described in US Pat US 5,713,892 shown.

In order to determine the position of the center of the pupil of the eye after pupil dilation, a method and a device in US 5,740,803 specified.

The exact regulation and determination of the location of the interaction of a surgical laser and the control of the corneal profile during ophthalmological surgery by means of an applanator are described in US Pat US 5,549,632 contain.

The favorable design of the beam profile by means of a specially manufactured, at different locations differently thick, laser-opaque membrane, which is positioned during the surgical treatment between the ablation laser and the cornea is in US 5,807,379 shown.

In WO 98/19741 discloses an apparatus and a method for laser thermal Keratoplasty presented the scanning of treatment areas allow the cornea with such forms that diminish the regression. The changes in of corneal refractive power are selected by selected local, oblong, pointed, photothermal shrinkage patterns in corneal Collagen tissue generated by laser scanning. The goal is stress optimization in the cornea. As the treatment laser, e.g. Used laser diodes, in the wavelength range from 1.3 to 3.3 microns in absorption lengths of 200 to 800 microns in the corneal tissue.

Alles The methods mentioned have in common that they are the imaging behavior of the eye through the change the curvature of optical interfaces (the cornea) influence.

In DE 41 31 361 C2 a device is described which contains an ultraviolet radiation emitting excimer laser, a radiation pattern generating device, an imaging optic and fixative for the eye, the UV radiation with its wavelength lies in the absorbing area of the cornea and its intensity is chosen so that with the absorbed UV radiation within the cornea, chemical structures are irreversibly changeable and thus the refractive index of visible radiation is variable, but no corneal erosion can take place and that the radiation pattern generating device causes a location-dependent exposure of the cornea with the UV radiation, whereby the refractive index is spatially dependent changeable , In DE 41 31 361 C2 it is also reported that chemical bonds can be broken by the short wavelength of excimer lasers.

From High-energy ultraviolet radiation is known to be special in the spectral range from 240 nm to 280 nm a very high mutagenic Carries risk, by resonance absorptions in RNA and DNA.

Of the Invention has for its object to provide a device with which by simple means safe and reproducible vision defects can be corrected without high-energy UV radiation with the to use their own mutagenic risk.

These Task is according to the invention solved by a device having the features of claim 1. Advantageous embodiments The invention are contained in the subclaims.

The device for irradiating the eye for the correction of visual defects may consist in particular of a treatment radiation emitting light source, means for temporal modulation of the treatment radiation, means for controlling the intensity of the treatment radiation, means for spatial modulation of the treatment radiation, optics for transforming and shaping the treatment radiation for introducing the spatially modulated radiation into the eye, means for determining the orientation of the eye lens axis and means for fixing the eye and / or eye-tracking, wherein the light source irradiated treatment radiation has wavelengths in the long-wave UV-A range above the corneal absorption and / or in the visible and / or near-infrared spectral range, which are absorbed in the eye lens and in that the means for spatial modulation of the treatment radiation emitted by the light source both a structured phase characteristic as well as a structured amplitude characteristic can imprint and that the optics for transformation and shaping of the radiation has at least one optical axis and the phase characteristic with respect to the amplitude characteristic and spatially modulated treatment radiation in predetermined e regions of the eye lens is transformed, whereby an adequate complex refractive index variation and / or transmission variation in the eye lens, which is desired both in terms of magnitude and spatial structuring, is produced, at which an effective radiation impinging in the application case is influenced in such a way that an optimized , error-reduced image arises.

at the device can the means of spatial Modulation and optics for transformation and beamforming in particular interact in such a way that a reduced-error vision also is possible at different accommodation states of the eye lens.

One particular advantage of the invention is that mutagenic risks be avoided by the eye lens defined with treatment radiation in the long-wave UV-A region above the cornea absorption and / or can be irradiated in the visible and / or near-infrared wavelength range, being locally photoinduced irreversible chemical changes in the eye lens Substance can be generated such that the refractive index and / or the transmission property for visible useful radiation is changed according to predetermined parameters and a reduced-vision results, with the defined Treatment irradiation by a spatial structuring and temporal modulation and an intensity control is realized. The spatial Structuring results from spatial Modulation and optical transformation.

The Generation of refraction changes in Eye is done effectively and with simple means by the device according to claim 1 and in particular a device for irradiation of the eye, which consists of a radiation emitting light source, means for temporal modulation of the radiation, means for intensity control for the Radiation, means for spatial Modulation of radiation, optics for transformation and shaping of radiation for introducing the spatially modulated radiation into the eye, means for determining the orientation the eye-lens axis and means for fixing the eye and / or for eye tracking, wherein the radiation emitted by the light source wavelength in the long-wave UV-A region above the corneal absorption and / or contains in the visible and / or near-infrared spectral range, which be absorbed in the eye lens and become photoinduced chemical Changes in the Lead eye-lens substance, what with appropriate intensity control and with appropriate temporal modulation of the radiation in the Eye lens to a refractive index change for radiation, not but to strong, pure amplitude components cataract-like Turbidity in the Eye lens area, and that the means of spatial modulation of the The radiation emitted by the light source is both a structured one Phase characteristic as well as a structured amplitude characteristic impress can, and that the optics transform and shape the radiation has at least one optical axis and with respect to the phase characteristic and amplitude characteristic spatially modulated radiation transformed into predetermined areas of the eye lens becomes, whereby one both after the amount and after the spatial Structuring desired adequate Refractive index variation and / or transmission variation in the Eye lens is created.

at a method of irradiating the eye to correct vision defects by refractive power change Then the eye lens can be defined with treatment radiation in the long-wave UV-A region above the cornea absorption and / or in the visible and / or near-infrared wavelength range irradiated be, being locally photoinduced irreversible chemical changes of the ophthalmic lens substance are generated such that the refractive index and / or the transmission property for visible Nutz radiation is changed according to predetermined parameters and a reduced error See results.

there can the defined treatment irradiation by a spatial and temporal modulation and intensity control can be realized.

Especially can the spatial Modulation of treatment radiation both a structured phase characteristic as well as a structured amplitude characteristic imprint.

In the method spatially modulated with respect to phase characteristic and amplitude characteristic radiation in a predetermined Berei the eye lens are transformed, whereby the adequate complex refractive index variation and / or transmission variation in the eye lens desired both in terms of magnitude and spatial structuring is produced, at which the useful radiation incident in the application case is influenced in such a way that an optimized , mismatched image emerges.

The Determination of the parameters to be specified can be done by (re) transformation calculations. From this, the required to correct the refractive error complex refractive index distribution with phase and amplitude components be determined.

The Laser radiation can be emitted continuously or with a time pulse become.

Furthermore can be an extra Sensitization of the content of the eye lens for the treatment radiation, especially by pharmacological or biochemical means.

at The method can by the intensity control for the treatment radiation the individual optimum of the exposure energy is determined in a pilot beam path by means of pulsed radiation in an edge region of the eye lens a sample refractive index variation built in stages and with optical means regarding their Amount is proven.

Further can the wavelength the treatment radiation, which is well above the excimer laser waves is, preferably larger to be 600 nm.

The Invention will be described below with reference to at least partially in the Figures illustrated embodiments be explained in more detail.

It demonstrate:

1 A schematic diagram of the device according to the invention,

2 an implementation of a detail 1 with multiple optical axes,

3 a sectional view of the eye lens with different levels of refractive index variations AA to ZZ,

4 a plan view of a simple structure of refractive index variations in a plane DD of the eye lens,

5 a plan view of an irregular structure of refractive index variations in a plane FF of the eye lens,

6 a two-dimensional optical structure having an amplitude or phase characteristic in the mask plane for the generation of refractive index variations in a plane GG of the eye lens, wherein different amplitudes are represented by gray values, and phase components are punctured and

7 a scheme for creating the "records after the inverse transformation" by "simulated optical return transformation" of the planar scheme for the necessary refractive power changes from the targets for the refractive power structure after the correction and the records to the existing refractive power structure in the eye to be treated.

The device according to the invention consists according to 1 from a light source 10 which radiation treatment 11 having a wavelength well above the excimer laser wavelengths, advantageously greater than 600 nm, and having temporal modulation means 12 , Means for determining the required and permissible exposure parameters 13 For example, by backscatter measurements on oblique pilot beam, and means for intensity control 14 is provided, means for spatial modulation 20 the treatment radiation 11 , which electronic signals 21 or signal chains, preferably in a computer 22 be generated in at least one-dimensional optical structures 23 convert, which may have both a phase characteristic and an amplitude characteristic, an optics 30 that have at least one optical axis 33 has, for beam forming or transforming the optical structures 23 to the place of application in the eye lens 77 , a device for determining the orientation 71 the eye axis with respect to the main axis of optics 30 as well as means for fixation 72 of the eyeball 70 ,

In 2 , is an advantageous embodiment of a detail 1 to see in which the "at least one optical axis" from the three optical axes 331 . 332 . 333 exists, with the optical axis 331 has the function of the main optical axis. In this embodiment, the transformation into predetermined areas of the eye lens may be effected by a superposition of more than one beam, that is to say adequately with at least one optical axis. The spatial modulations can be different in the individual partial beam paths.

The basic treatment sequence of three selected examples will be presented below provides.

example 1

From Defective vision is principally the amount and the azimuthal Distribution known.

By (Re) transformation calculations will be from this a complex refractive index distribution (phase and amplitude components) determines which in the eye lens must be present to the To correct ametropia.

In dependence the fineness of the required structure as well as the depth of modulation The refractive index distribution becomes the type of optical system (simple Transformation of the radiation by means of an optical axis or Superposition of radiation over several optical axes, in other words a simple one Flat-screen projection to coherent Multibeam overlay) established.

The wavelength radiation and its coherence properties become dependent determined by the desired refractive index structure.

Of the Power range of the light source and its time regime (pulse duration, Pulse rate and pulse rate) are also set. By appropriate determination the application parameter is to ensure that the "total Cataract "avoided becomes.

through Computer technology becomes concrete from the necessary refractive index structure determines which spatially modulated structure of the radiation in cooperation with which Transformation and beam shaping optics this refractive index structure the cheapest realized in the eye lens. It can be quite advantageous prove that in different areas of the eye lens so significant amplitude changes have to be generated already cataract-like Possess properties, but in the interaction of the entire structure in the eye lens lead to the improvement of the eye's vision, which across from outweigh the low transmission losses.

The spatial Modulation can be achieved by both electro-optical transducers in transmission or reflection as well as by scanners, as well as in different ones Coordinate systems, for example, Cartesian or polar.

is the structure in the eye lens exists, so it works with their (for example, predominantly existing) phase fractions (refractive index variations) and also with their (sometimes existing) amplitude components (transmission variations) as a complex imaging diffraction structure, which is the refractive power improved in the eye so that an error-corrected vision is possible.

It It is also possible to realize structures such as accommodation movements the eye lens for a larger accommodation area optimal See enable.

Example 2

From the refractive error of an eye is in turn the amount and the Azimuthal distribution of refractive power deviation known. They become conventional Determined way. It is useful, to know the refractive power structure in the eye in a very narrow grid. (much smaller than 0.1 mm)

Farther it is very useful the change the refractive error in a manageable past To know the period.

outgoing the amount of ametropia and change behavior (relative stability or strong changes in a certain period of time) becomes the principal possibility of treatment. The treatment should not be applied when the refractive power becomes very strong within a short time changed. (for example, more than 2 diopters in one year). Because the eye to be introduced corrections have a good long-term stability.

The Treatment is very suitable if strong or very irregular deviations above the Azimuth or over the distance from the visual axis. The more complicated the Refractive power structure is, the more promising is the method applicable.

The Treatment is very suitable if the visual performance is particularly at low brightness or in lighting with predominantly long-wave radiation (Warm lighting) should be improved.

The Treatment is non-invasive, contains no infectious risk, no mutagenic risk due to high energy radiation and can be practiced on an outpatient basis.

Depending on the amount of required refractive power correction, it is decided whether the treatment is purely projection along an optical axis 33 (please refer 1 .) or as a coherent-optical superposition with more than one optical axis 331 . 332 . 333 (please refer 2 ). The latter must be used if the refractive power change is to be very strong. The required refractive index variations must be generated in this case in microscopic dimensions (about 1 micron or even smaller).

Of the individual indication is taken for which wavelength and Angle range the correction should be adjusted as best as possible. Of these, the determination of the light source wavelength is dependent.

The temporal action regime (cw, qcw or pulsed operation as well as the pulse length and Repetition frequency) are still according to to be specified Determine investigations.

pulse operation with frequencies near the kilohertz range, with pulse lengths of Micro to milliseconds were successfully used.

On the basis of the required refractive power change, the light source wavelength and the selection of projection or superposition, a suitable optics is selected. By specifying this optic, the type of spatial modulation can be calculated using computational methods 20 (a possible example of such a "mask" is in 6 , shown), which after the optical transformation in the eye lens 77 Intensity structures leaves behind, which generates the intended adequate spatial distribution of a refractive index structure with the set time exposure parameters. In the 4 and 5 Two such conceivable intensity or refractive index structures can be seen, in 4 for a simple case, in 5 for a slightly more irregular case. The distances within the structures can vary, they can be small or larger, they can increase or decrease in one direction or change. Resulting orientations of the structures in the azimuth may include any angles according to the correction requirements.

Narrower distances in the structures are synonymous with stronger directional change of Light rays, so with stronger Power. The deflection is in accordance with the laws of diffraction optics orthogonal to the structure dimensions.

For the purpose of efficient power correction, several to many such refractive index patterns graduated in the depth of the eye lens are required. That is in a schematic sectional view in 3 , to see.

Example 3

The eye to be treated is examined. The distribution of the refractive power of the eye (not just the lens, but the entire optical path in the eye) is determined in a very close-meshed, flat grid parallel to the lens plane. This results in a first data set DS1 (eg in a computer) for the state of the refractive power distribution in the eye (see scheme in 7 .). The state to be corrected can be analyzed more accurately if the refractive power structure is determined not only in or parallel to the optical axis but also at different inclinations to the optical axis.

Out the difference of the detected actual state DS1 with the targets ZV (as the desired Refractive power after the correction should be) creates a planar Scheme FS, which shows the necessary refractive power changes for specific sections the eye lens describes. These subareas can be very small, at very irregular power structure have to they even be very small against the lens size. For more detailed investigations is it advantageous to different areal Schemes FS under different inclinations against the optical axis to determine the eye.

The planar scheme FS is subjected to a computer of a simulated optical return transformation SOR. For this, certain concretions must be made to the device with which the correction method according to the invention is to be carried out (optics to be selected, wavelength of the light source, number of points in the areal scheme FS and in the means for spatial modulation 20 ). The simulated optical return transformation SOR is performed iteratively.

As a result, there is a group of records after the reverse transformation DRT. Each data set serves to generate a structure of refractive index variations in one of the various layers AA to ZZ in the eye lens (see 3 .)

The concrete method for treating the eye requires that the corresponding data records after the reverse transformation DRT in a computer 22 available. This will become chains of electronic signals 21 generated in the means of spatial modulation 20 of treatment radiation from the radiation 11 a light source 10 several at least one-dimensional optical structures 23 which may have an amplitude or phase characteristic generated. This is modulated in time and in its intensity by the computer 22 regulated.

About an optics 30 becomes the optical structure 23 either in the eye lens 77 projected into or through a multi-beam superposition along the sub-beams 331 . 332 . 333 the structures 231 . 232 . 233 in the eye lens 77 superimposed.

It is necessary the eye 70 with funds 72 to fix. Depending on the means 71 Certain eye-axis alignment may require fine adjustments the location of the structure 23 eg by changing the signal chain sequences 21 be made.

The means 13 serve the determination of the required effect parameters and a retroactive effect of the determination of the admissible influencing parameters, in particular of the "distance" to inadmissibly high acting performances 13 consists in a real-time control path, in which the refractive power changes achieved and the data from the area-wise scheme FS specify the control variables.

Claims (6)

Apparatus for irradiating the eye for the purpose of correcting vision defects, comprising a light source ( 10 ), the treatment radiation ( 11 ) emitted with wavelengths in the long-wave UV-A range above the corneal absorption and / or in the visible and / or near-infrared spectral range, which in the eye lens ( 77 ) and locally produces irreversible changes in the lens substance, means for temporal modulation ( 12 ) and intensity control of the treatment radiation ( 11 ), Means for spatial modulation ( 20 ) of the treatment radiation ( 11 ), an optic ( 30 ) with at least one optical axis for introducing the modulated treatment radiation ( 11 ) into predetermined areas of the eye lens, means ( 71 ) for determining the orientation of the optic-lens axis and means ( 72 ) for fixation of the eye and / or eye-tracking. Device according to claim 1, characterized in that that the means of spatial Modulation electro-optical converter included. Apparatus according to claim 2, characterized by in reflection working electro-optical converter. Apparatus according to claim 2, characterized by in transmission working electro-optical converter. Device according to Claim 1, characterized in that the means for spatial modulation ( 20 ) Scanners included. Device according to claim 1, characterized in that that the optics contains a scanner.