EP1988816A2

EP1988816A2 - Ophthalmological appliance

Info

Publication number: EP1988816A2
Application number: EP07722902A
Authority: EP
Inventors: Egon Luther; Ingo Koschmieder; Joachim Winter; Uwe Mohrholz; Manfred Dick; Thomas Mohr; Daniel Bublitz; Enrico Geissler
Original assignee: Carl Zeiss Meditec AG
Current assignee: Carl Zeiss Meditec AG
Priority date: 2006-02-28
Filing date: 2007-02-22
Publication date: 2008-11-12
Also published as: US20090257024A1; WO2007098882A2; WO2007098882A3; JP2009528101A; US7871164B2; DE102006010105A1; JP5227811B2; CN101389263A

Abstract

The invention relates to a device for the observation, documenting and/or diagnosis of an eye, especially the front eye section, the iris, the lens, the glass body, and the eyeground. The homogeneously illuminating ophthalmological appliance consists of an illumination device provided with an illumination source (1), a homogenisation unit (2, 3, 5), and a projection device (7), at least one organic or inorganic radiation source with spectrally selective emission being used as an illumination source. The illumination generated in this way enables correspondingly adapted visual and/or digital observation, recording or display of the examined regions of the eye on a visualisation unit. For homogenisation purposes, the light emitted from the radiation sources (1) is collimated by means of a condenser lens (2) and imaged onto the microlens array (3) consisting of respectively opposing spherical surfaces (3.1 and 3.2) arranged at a distance (3.3) corresponding to the focal distance of the microlenses.

Description

Ophthalmic device

The present invention relates to a device for observing, documenting and / or diagnosing the eye, in particular the anterior segment of the eye, the iris, the lens, the vitreous body and the fundus of the eye.

According to the known state of the art, conventional white light sources are used for illumination in conventional ophthalmological devices for examining the eye, in order to produce the most natural possible image of the interior of the eye for the observer. In order to enable investigations in special spectral ranges, appropriate spectral filters are used in the beam path after the white light source.

A disadvantage of these conventional white light sources, such as halogen lamps, that from an energetic and economic point of view, the light is generated only with a relatively low efficiency of 8 -12%. A significant part of the spectrum is also outside the visible range, with the UV and IR components are filtered out to prevent damage to the eye by the lighting.

This disadvantage is exacerbated when only very narrow spectral ranges, for example from the UV range, are used to perform fluorescence studies. Accordingly, in this conventional lighting, a high expenditure on equipment for the mechanically movable optical filters and for cooling the system is necessary.

Another disadvantage of conventional white light sources is the switch-on and switch-off behavior, which is characterized on the one hand by relatively long switching times (in the range> 100 ms) and on the other hand by variation of the spectral composition of the light in the switch-on phase. In addition, halogen lamps have a relatively long warm-up phase. In the known prior art, using halogen lamps slit lamps, the light of the halogen lamp is parallelized with a condenser lens and then illuminates a gap that is adjustable in width. The light that passes through the gap is then imaged by an optical system sharp into the anterior chamber of the eye to be examined. The light backscattered by the eye is imaged on a camera with a second detection optics and / or allows the visual observation of the eye. In order to vary the angle between illumination and detection beam path, the illumination beam path is angled in front of the eye by a prism. This deflecting prism is located approximately in the pupil plane in front of the eye. Since all illumination beams must transmit through the prism exit surface, this deflection prism limits the light conductance of the illumination source. It is important that the light passing through the slit in the illumination source is as homogeneous as possible, since this homogeneity is transmitted through the image into the eye as far as the focal plane of the slit lamp.

Since the homogenous gap illumination in the prior art is achieved by a condenser lens arranged in front of the halogen lamp, the gap is in the pupil plane of the incandescent filament of the halogen lamp, so that the homogeneity in the cleavage plane thus corresponds to the intensity homogeneity in the angular spectrum of the incandescent filament of the halogen lamp.

Due to the relatively long switching times, an additional fast shutter is required, especially for short exposure times, which feeds the light of a "burned-in" lamp into actual use, which is particularly disadvantageous for moving examination objects, such as the eye, because here very short exposure times in ms Range needed to exclude motion effects when documenting the eye.

In a known embodiment, the document EP 1 114 608 B1 describes an ophthalmic irradiation system which uses illumination based on LEDs in a subcomponent of the overall system. det. In the subclaims, it is stated that the device essentially serves to emit certain quantities of red, green and blue light in order to generate substantially white light. The individual light regulation serves to maintain the color shade when the protective filter is swiveled in and out. The document EP 1 114 608 B1 thus describes in a special sub-construction an illumination system based on LEDs, which serves to maintain the color neutrality in combination with an optical protection filter.

Document EP 1 602 323 A1 describes the use of a white LED as illumination source in a classic slit lamp. In contrast to the classic slit lamp illumination described above, the homogeneity in the cleavage plane corresponds to the intensity homogeneity in the angular spectrum of the chip area of the LED. However, since the optical properties of the light emission of an incandescent filament and an LED chip area differ significantly, this also has negative effects on the achievable homogeneity. Whereas an incandescent filament emits approximately a spherical wave with homogeneous intensity in the angular spectrum due to the curved shape of the filament, a lambertian angle spectrum is emitted to a good approximation by an LED chip functioning as a surface radiator. This means that the light intensity decreases with the cosine to the LED chip surface normal. This results in a systematic edge drop in the cleavage plane, which depends on the aperture of the condenser lens, wherein an aperture of NA = 1 corresponds to a boundary drop of 100%. This edge drop can not be completely prevented in the case of "geköhlerten" lighting, but only by reducing the aperture of the condenser lens limits, but on the other hand, the energy efficiency of the illumination source greatly reduced A special advantage of this device - compared to slit lamps on the basis of halogen illuminations - is the high color constancy of the light at different intensities In EP 1 602 323 A1 thus a classic slit lamp is described, which uses a white LED or red, green and blue LEDs to generate white light as a radiation source.

- 3 - The document US Pat. No. 5,997,141 A describes a system which uses arrays of LEDs for the illumination on the eye. The document US Pat. No. 4,699,482 A describes a lighting device which uses LEDs in combination with optical fibers to illuminate the eye.

All these writings with locally distributed emitters have - without special devices for homogenization - the disadvantage that the intensity in the field of illumination is not sufficiently homogeneous and is insufficient for a sensitive diagnosis.

The present invention has for its object to provide a solution to an energetically economical and applicatively improved lighting device for an ophthalmological device, which in particular by a spectrally selective, very homogeneous, multi-channel light generation with short switching times and high spectral stability in the switch-on and short-term Emission is marked.

According to the invention the object is solved by the features of the independent claims. Preferred developments and refinements are the subject of the dependent claims.

A particularly advantageous applicative property of this novel illumination device is, for example, the possibility of providing high spectrally selective intensities in the UV-near range> 400 nm. There, the ocular media have the highest scattering power in the visible range and can make the most sensitive diagnoses.

On the other hand provides the use of LED ^'s at 1065 or 1300 nm in the smallest scattering ocular media and even lower water absorption z. B. through cataract lenses through the rear side and the rear capsular bag membrane to investigate.

- A - The idea of the invention thus describes the use of very specific spectra in combination with very short switch-on or switch-off times with high color constancy, for the purpose of increasing the sensitivity of the diagnosis on the eye.

The invention will be described in more detail below with reference to exemplary embodiments. To show:

Figure 1: an arrangement for homogenizing the light of the radiation sources on the basis of a microlens array and

FIG. 2 shows an arrangement for homogenizing the light of the radiation sources on the basis of a hollow integrator.

In the ophthalmic apparatus according to the invention with homogeneous illumination for observing and / or documenting an eye, comprising an illumination device with an illumination source, a homogenization unit and a projection device, one or more, spectrally selectively emitting radiation sources on an organic or inorganic basis are used as the illumination source.

Depending on a control unit, these radiation sources generate continuous and / or pulsed spatial illumination in order to enable a correspondingly adapted visual and / or digital observation, recording or output of the examined regions of the eye via a digital camera unit.

In particular, LEDs, SLDs, lasers or O-LEDs are used singly or in combination as spectrally selectively emitting radiation sources on an organic or inorganic basis. The illumination source preferably has a plurality of spectrally selectively emitting beams. sources with equal and / or different intensity distributions as a function of their wavelength. The intensity distribution of the radiation sources are broadband, narrowband or monochromatic or are formed by combinations thereof.

While radiation sources in the visible spectral range (white light) predominantly have a broadband intensity distribution, radiation sources for excitation of fluorescence have as narrow as possible a monochromatic intensity distribution with a half-width <= 50 nm in a preferably Gaussian course with a central peak.

The illumination device has for emitting a broadband spectrum of preferably 400 to 700 nm via one or more radiation sources, which preferably emit a monochromatic (blue) spectrum of 400 to 490 nm and are coated with a luminescent dye for color conversion. This ensures that the vast majority of the emitted white spectrum is in the blue region. Such an intensity course, for example, LEDs OSRAM Dragon LW W5SG on. The color locus is on the white curve in the standard color chart, but in the blue area.

Such LEDs, which emit light in the blue region of the white spectrum, have the advantage that in the shorter wavelength range, a higher scattering occurs on the media of the eye, which enables an improved diagnosis.

In a further embodiment, an LED is used which emits a monochromatic spectrum in the UV range (<400 nm) and is coated with a luminescence dye for color conversion. Such an LED has the advantage that no emission of the excitation wavelength (<400 nm) takes place in the visible range (400-750 nm). In this case, the color conversion luminescent dye may preferably be designed so that the resulting

- R - The emission spectrum approximates the course of the V (λ) curve, which describes the course of the spectral sensitivity of the human eye, and is therefore perceived by the human eye as almost "perfectly white".

In principle, it is also possible to produce white light by a combination of monochromatic radiation sources, such as red, green and blue LEDs. In this case, it is possible by means of suitable combinations to produce a very specific distribution function of the white light.

As narrow-band, monochromatic LEDs with a half-value width of <= 50 nm, with a preferably Gaussian distribution with a central peak, LEDs of OSRAM, type LB W5SG (blue), LV W5SG (verde / blue-green), LT W5SG (green) or LE R A2A (red) used.

Narrow-band illumination allows diagnosis in special spectral ranges. The observation can take place in the visible range directly or with illumination in the non-visible range by means of an electronic camera and the conversion / transmission of information in the visible range, for example by means of false color representation on a display. For example, certain intensity values in the non-visible range can each be assigned colors in the range 400-700 nm and displayed on the display.

Advantageously, the selection of desired wavelengths can take place via the actuation of selected monochromatic radiation sources.

As a result, a significantly simplified and improved operation is achieved because it is possible to dispense with mechanically moving optical filters.

However, illumination devices for emitting a broadband spectrum are also suitable for a spectral range of preferably 700 to 1100 nm

- 7 - possible, wherein one or more radiation sources are used with a half width of at least 20nm.

For visual and / or digital observation, recording or output, a digital camera unit sensitive in this spectral range is to be used here.

The narrowest possible, monochromatic intensity distributions of the radiation sources for excitation of fluorescence range from the UV to the IR range.

While wavelengths in the UV range starting at approximately 180 nm are suitable for documenting the fluorescence images excited by an excimer laser, wavelengths in the IR range up to approximately 2 μm are used for images with little scattering of the radiation in the tissue and even more adequately To document water absorption. From a wavelength greater than 2 μm, the penetration depth is only sufficient for the cornea and thus no longer suitable for imaging.

As radiation sources for the emission of IR spectra, for example, OSRAM SFH4230 LEDs are used which emit radiation in the range of 700 to 1100 nm, with a half-width of 40 nm and a peak wavelength of 850 nm, in a Gaussian distribution.

Since the illumination also takes place here in the non-visible spectral range, a digital camera unit that is sensitive in this spectral range is required for observation, recording or output.

This embodiment variant is particularly advantageous because no or only very little irritation of the eye takes place here and no mydriatics is required, which results in a narrowing of the pupil. As a result, diagnoses are in the IR range, by transmission / conversion of information the IR range in the visible range, for example by means of false color representation on the display, possible. Despite a reduction in the radiation exposure of the patient, reliable diagnoses are possible.

In a further embodiment, it is also possible to combine a broadband radiation source and monochromatic radiation sources in order to generate special intensity distributions. The combination of radiation sources which do not overlap in the spectrum can preferably be effected by means of dichroic mirrors, which are imaged onto a common aperture. In particular, in the combination of different radiation sources is to ensure that the beams generated by the individual radiation sources match at the coupling point to the ophthalmological examination device in aperture and aperture angle.

In another advantageous embodiment, a plurality of laser sources are used for the illumination. The colinear imaging of the individual laser beams can preferably be effected by means of an optical grating or a prism. Optionally, the narrow-band spectra with a typical half-value width of, for example, +/- 3 nm can be widened to a half-value width of +/- 20 nm using optical conversion signals. In this case, fluorescent dyes can be used as optical conversion coatings.

To produce the most uniform possible intensity distribution, the illumination device has a homogenization unit in the form of a light integrator or light mixer, which is arranged in front of the radiation sources. In particular, a hollow integrator or microlens array is used here as the homogenization unit. With the homogenization unit, the light emitted by the radiation sources is homogenized in terms of intensity, color and angle spectrum. The light homogenization should take place by the adaptation of the light conductance of the radiation sources to the illumination optics with the highest possible light efficiency.

- 9 - 1 shows an arrangement for homogenizing the light of the radiation sources on the basis of a microlens array. The light coming from the radiation sources 1 is collimated with a condenser lens 2 and imaged onto the microlens array 3. The microlens array 3 consists of respective opposing spherical surfaces 3.1 (input plane) and 3.2 (output plane) with a distance 3.3 corresponding to the focal length of the microlenses. As a result of the interaction of the condenser lens 2 and the microlens array 3, the radiation source 1, consisting, for example, of individual LEDs, is imaged as far as possible into the imaging lens 5 arranged behind the microlens array 3.

Behind this imaging lens 5, for example, a slit diaphragm can be arranged in the image plane 6 with which the slit illumination required for a slit lamp is generated. The gap thus generated is projected via the projection device 7 and a deflecting prism 8 in the eye 9, wherein the angle of incidence of the illumination can be varied.

The homogenization of the illumination radiation achieved in this way can be illustrated as follows:

The pupil of the radiation sources 1 is located exactly in the input plane 3.1 of the microlens array 3, wherein the light distribution through the microlenses in exactly as many channels as there are microlenses. The light of each channel is then imaged via the imaging lens 5 in the image plane 6 and superimposed there with the light of all other channels. When using LEDs with Lambertian radiation profile as the radiation source 1, a cosinusoidal intensity distribution in the input plane 3.1 of the microlens array 3 can be observed. However, since the light of each microlens is imaged by the associated second microlens and the imaging lens 5 on the entire image field, an almost perfect homogenization in the image plane 6 can be achieved

- 10 - become. The angle spectrum behind the image plane 6 is also much more homogeneous than in the classical lighting.

In an advantageous embodiment, the use of microlens arrays with honeycomb cross-sections of the individual lenses is provided. This is particularly advantageous for the generation of a slit illumination. When using one or more white LEDs has the advantage that the illumination of the gap in the image plane and in the Forderkammer of the eye is substantially homogeneous than in classic "geköhlerten" lighting and has almost no edge drop more, which in particular for the realization of higher quality Measurements are crucial.

For this purpose, the measurement of the turbidity of the eye lens in cataracts called. This also makes it possible, for example, for the adaptation of contact lenses, to use the brightness of a fluorescence contrast agent as a measure of the gap size between the eye and the contact lens.

Even greater improvements in illumination can be achieved by using LED arrays with an RGB structure. In such LED arrays, the three basic colors (red, green, blue) z. B. arranged in a square structure, wherein the color green is duplicated and facing diagonally. If such an LED array with a conventional optical system is imaged in the eye, then due to cut-off errors in the deflection prism, color distortions can occur and a white gap-shaped illumination is thus produced only in the focal plane of the gap image. However, since in a slit lamp sectional images of the Augenforderkammer should be recorded at different depths simultaneously, it must not come in front of and behind the focal plane to Farbbartefakten. Such color bar artifacts are prevented by the microlens array homogenization described herein.

- 11 - For these reasons, the use of a homogenizer for slit lamp illumination is a crucial advantage and a key innovation that goes beyond the state of the art in the use of LEDs in the slit lamp lighting.

In another embodiment, FIG. 2 shows an arrangement for homogenizing the light of the radiation sources on the basis of a hollow integrator.

The light coming from the radiation sources 1 is collimated with a condenser lens 2 and imaged into the hollow integrator 4. By reflections within the hollow integrator 4, the light of the radiation sources 1 is homogenized and in the image plane 6 in which a slit diaphragm can also be arranged in order to produce the slit illumination required for a slit lamp. The gap thus generated is projected via the projection device 7 and a deflecting prism 8 in the eye 9, wherein the angle of incidence of the illumination can be varied.

The two mentioned variants for homogenization, which are particularly compact and inexpensive to implement, have visually similar properties.

This ensures that the entire emitted radiation is forwarded by the projection device into the ophthalmological examination device. By using digital camera units, radiation sources with a flat, rectangular radiating surface are optimal.

The result of this advantageous embodiment is an improved efficiency and the reduction of temperature-dependent effects. The much more even light field also improves the variety of possible diagnoses and their reliability.

, 10. The control unit will control and monitor the timing, duration and intensity of the radiation sources individually, collectively or in groups to generate specific illumination spectra.

In this case, the control of the one or more camera units can be tuned to the wavelengths of the light emitted by the lighting module and synchronized with their lighting duration.

For example, at least one but preferably several images may be recorded in different colored lighting conditions with an exposure time of a few milliseconds. These monochromatic images can then be combined to form a colored image. Targeted differences in monochromatic images can also be evaluated.

An advantage of this embodiment is that no mechanically moving filters are required that different diagnoses can be carried out with only one device, that by temporal modulation of the radiation source and synchronous, assigned recording several monochromatic recordings can be realized, which evaluated defined or even to a chromatic Mixed image are summarized without thereby increasing the radiation exposure of the patient.

In addition, the control unit determines, monitors and corrects the optical power and / or the geometry of the light emitted by the radiation sources to keep the radiation exposure of the eye as low as possible and within acceptable limits.

This also results in the possibility of automatically adapting the radiation power when changing the illumination pattern, adjusting the type-related fluctuations in the properties of the radiation source, in particular intensity fluctuations, which may also be due to aging.

_ Λ 'X _ Within the framework of observing the permissible radiation exposure of the eye, the control unit should monitor important setting values of the ophthalmological device, such as, for example, currents and / or voltages for determining the radiation dose. A distinction should be made between wavelength-specific hazards, such as thermal and photochemical hazards to the eye.

In the safety-critical case, the control unit should have means for reducing or shutting off the supply of the radiation source.

The use of spectrally selective emitting radiation sources on an organic or inorganic basis continues to offer significant advantages.

On the one hand, such radiation sources are distinguished by a good dimming capability with an almost constant color temperature, with only a very slight color shift (of <0.02) in the standard color chart, which substantially improves the reproducibility of diagnostic results given different radiation powers of the radiation source. Even a heating of the radiation sources leads only to a very small shift of the color locus (of, for example, 0.0002 / ⁰ C) or the peak wavelength (of, for example, 0.04 nm / ° C).

On the other hand, these radiation sources are also characterized by very short on and off times (from 0% to 100% of the rated current), which are in the range of ms or even μs. Thus, a specific operating point (eg a specific current value) in the μs range can be switched on and off again via pulse width modulation, and a brightness control can be performed with an identical operating point. This results in a further possibility for stabilizing the color temperature and thus for a better reproduction of diagnostic results at different radiation powers of the beam source.

, Λ A _ In addition, an improved signal-to-noise ratio is achieved, wherein the light dose can be kept as low as possible by the short-term increased radiation exposure.

Furthermore, the radiation sources offer the possibility of a short-term overload without damage, with the amount of overload depends on their duration. The duration of a 3-times rated current overload is in the ms range for LEDs.

Last but not least, the radiation sources have a comparatively long service life, which is more than 10,000 hours depending on the type. Thus, device design can be developed for the overall ophthalmic device that does not provide for the replacement of the radiation source during operation.

Although mechanically moving filters are not required, optical filters offer the possibility, in particular in the UV and IR ranges, to limit the emitted spectra in a defined manner by means of edge filters. The edge wavelengths of the optical filters are typically 380, 400 or 420 nm in the UV range or 700 nm in the IR range.

In order to ensure sufficient light output, it must be ensured that the radiation sources used have an optical minimum power and emit the light locally evenly from the emitting surface. Furthermore, the intensity of the radiation source should be continuously adjustable over a wide range and the color temperature over the entire range of intensity should be largely constant.

In today's standard ophthalmic devices, powers of 10 to 20 W are achieved in the visible spectral range (400 to 700 nm), which corresponds to about 1 W of optical power.

- 15 - In the non-visible, infrared spectral range (700 - 1100nm) as well as monochromatic radiation sources, on the other hand, only optical powers of about 0.1 W are achieved.

In a particularly advantageous embodiment, the illumination device consisting of an illumination source and a projection device additionally has devices for geometrical and / or spectral manipulation of the emitted light, which are used selectively.

In this case, the radiation source of the radiation generation, the device for manipulating the generation of geometric and / or spectral illumination patterns and the focusing optics of the projection of the illumination pattern on and / or in the eye.

This allows special light patterns, such as slit illumination, o. A. be generated. But it is also possible optional optical filter, which can be selectively switched on and swung in the beam path, the filter preferably have wavelength-selective properties, such as high, low or band pass filter.

In order to avoid disturbing light influences during the visual and / or digital observation, recording or output, it is customary to preferably geometrically divide the illumination beam path and the observation beam path. A suitable technical solution is that a centrally arranged, vertical gap (slit prism) is used for the illumination and the observation preferably takes place laterally past it.

The control unit can either be integrated into the ophthalmological examination apparatus or designed as a separate unit connected via data lines and serves both to control the radiation sources and manipulation means for generating a continuous and / or pulsed structured illumination, as well as to control the digital camera unit for visual inspection.

- 1 fi - Hurry and / or digital observation, recording or output of the images of the examined areas of the eye.

A separately formed control unit preferably has a user interface with an operating unit, a keyboard, a display and a data output unit, with standard PC interfaces preferably being used as data lines. The data output preferably takes place via printers or standardized interfaces. Of course it is also possible to save the data on different data carriers, such as floppy disk, CD-ROM, DVD, various memory cards or the like.

The device for the generation and manipulation of illumination patterns can optionally be controlled electronically in order to simplify the communication to the control unit.

The control unit controls the corresponding radiation sources via the switch-on time and duration, as well as current and voltage, so that the desired spectral illumination pattern is produced.

In addition to these integrated radiation sources, these can also be embodied as separate units, wherein the radiation is guided, for example via optical fibers, to the ophthalmological apparatus and coupled into its illumination beam path. The advantage of such an embodiment is in addition to a very compact design of the ophthalmological device made possible by the possibility of a very individual adaptability of the lighting to the respective task to be solved.

In a further advantageous embodiment, the digital camera unit is designed so that it can be used as a device for visual observation, wherein the output of the image of the examined eye takes place on a display which is present on the camera or separately. optional In this case, for example, a contact glass can be used for increased observation.

It proves to be particularly advantageous if, in addition to the visual output of the image of the examined eye, important control and adjustment data of the overall ophthalmic system are also displayed on the display.

In addition to a visual observation of the images of the examined areas of the eye represented by the digital camera unit on the display, the digital camera unit serves in particular to record and output these images. For this purpose, the digital camera unit is controlled synchronously with the radiation sources used.

In a simple and inexpensive embodiment, the digital camera unit consists of a commercially available consumer camera, which preferably stores the recordings digitally on a transportable storage medium, such as a compact flash card, SD card, memory stick or the like. The data transfer for further processing and / or archiving can be done later on a separate PC with special software.

The control unit itself or a PC system connected via a data line serves to store the images of the examined eye, preferably in the form of a patient-related database. The system should allow both data export and import of patient-related data using standardized file formats (eg DICOM), as well as post-processing and extraction of functional features from the digital camera recordings in order to obtain relevant information for optimal diagnostics.

As part of the post-processing of the camera shots, it is expedient that the images evaluated in terms of quality and existing artifacts and optionally software in terms of image sharpness, contrast, pixel error, Marginal drop, distortion, color aberration, local offset or the like can be corrected.

In an additional embodiment, the ophthalmological examination device has a device (eg, beam splitter) with which a preferably variably adjustable part of the radiation can be coupled out to an existing opto-electronic interface. Various applicators can be connected to this standardized interface. Furthermore, this electronic control and monitoring of the coupled applicator is present.

For example, a flexible optical fiber configured as a stepped or gradient fiber for transmitting the optical radiation can then be connected to the standardized interface in order to provide a separate additional illumination. The flexible light guide is used, for example, for scleral illumination, so that the eye can be "backlit" illuminated, in particular for observation / documentation of cornea, iris, lens, capsular bag or existing implants.The or even more flexible light guide can also for a serve regrediente lighting.

Furthermore, it is possible that a flexible light guide communicates with a lighting module, which is mounted on the head of the doctor.

The relatively high efficiency of the lighting unit also enables a time-limited, mobile operation. The supply of the radiation sources takes place here by means of batteries.

The proposed technical solution offers further advantageous embodiments.

Thus, for example, an increase in the sharpness of the electronic images of the eye can be achieved by optical image stabilization, in

- 1 Q - in front of the electronic image sensor used as a visualization unit, a mechanically movable, optical element is arranged, with which existing movements of the eye - especially at longer exposure times - can be compensated. The same effect can be achieved if the electronic image sensor itself is mechanically movable. For these two optical image stabilization solutions, it is necessary to detect movements of the eye relative to the electronic image sensor. In this case, the detection of the movement of the eye can take place by means of a sensor with a corresponding evaluation algorithm, whereby the image sensor of the visualization unit can also be used.

An increase in the sharpness of the electronic images can also be achieved by using shorter exposure times in combination with higher light intensities of the radiation source and / or methods of electronic amplification or post-processing of the image data for image acquisition.

In a further embodiment, the electronic camera used as a visualization unit has several sensors. In one embodiment, each monochromatic radiation source of illumination is assigned a sensor in the observation beam path. The assignment can be made in the observation beam path z. Example by means of dichroic filters or a beam splitter filter combination. Thus, the exact same time recording of multiple monochromatic images is possible.

The same effect of capturing multiple monochromatic images at exactly the same time can be achieved by using a Foveon, Inc., Santa Clara, Foveon X3 ™ direct image sensor.

The recording of two monochromatic images with a very small temporal offset of a few milliseconds can be achieved by using a

_ on _ electronic camera with interline sensors for temporary storage of a recording, wherein the light sources sequentially very short on and off must be feasible. Such, temporally only slightly offset recording are achieved by first the first monochromatic light source is actuated and the electronic sensor makes an associated recording. This recording is buffered in the interline registers of the electronic camera. Immediately after switching off the first light source and turning on the second light source of the electronic sensor makes the second monochromatic recording. After that, both images are digitized by the camera and transferred to the PC.

By combining a beam splitter or a dichroic mirror with two cameras equipped with interline sensors, four monochromatic images with a very short time offset in the range of a few milliseconds can be produced by means of a sequentially operable beam source.

In a further special embodiment, the illumination takes place in the form of very narrow gaps which lie in the range of 10 μm to 1 mm, for which purpose a laser source with a very low light conductance and above all with very small divergence is used. This type of illumination is used in slit lamps, which can be used to examine details in the front of the eye. With adjustable magnification and special lateral illumination with the so-called light gap numerous diseases are recognizable. The laser source sends a short pulse in the range of μs up to a few milliseconds into the eye. This radiation, which is scattered on the media of the eye, is recorded by an electronic camera, whereby optionally an optical filter can be used, which is transparent only for the excitation wavelength of the laser.

It is also possible to use several lasers of different wavelengths sequentially or simultaneously. In doing so, the

- 91 - Taking the different wavelengths by means of electronic image sensors associated with the beam sources temporally or it is made a single shot with simultaneous illumination with multiple laser sources. The recorded scattered light shots can also be subjected to post-processing by software.

The special slit illumination described here combines the advantages of a very good signal-to-noise ratio and a very high depth of focus.

With the ophthalmological examination apparatus according to the invention with spatially structured illumination, observation and / or documentation of specific areas of an eye are possible. In particular, the proposed illumination device provides spectrally selective spectra of high intensities in the UV-near range> 400 nm. Since the ocular media have the greatest scattering power in this range, very accurate diagnoses can be made.

Since in the proposed solution can be dispensed with a Mydriatikum, the irritation of the eye is very low. Due to the possibility of a diagnosis in the IR range, there is no narrowing of the pupil during the observation. The diagnostic options are significantly improved and the radiation exposure of the patient is reduced.

Advantageously, the selection of desired wavelengths via the operation of selected monochromatic radiation sources take place, so that mechanically moving optical filters are no longer necessary and simplifies the device structure.

The advantage compared to existing solution is that only the wavelength necessary for the diagnosis is emitted by the radiation source, which also minimizes the radiation exposure of the patient

OO leads. Due to the large number of different selectable wavelengths, multiple diagnostics are possible with only one device.

Due to the fast switching times of the LED's a simple temporal modulation of the radiation source and synchronization to the camera unit is possible.

Compared to conventional radiation sources, the LEDs used have a much more uniform light field, better efficiency, lower temperature-dependent effects, a stable color temperature, improved efficiency, lower heat load and better reproducibility of diagnostic results at different radiant powers of the radiation source.

All these advantages mean that the diagnostic possibilities are improved by an improved signal-to-noise ratio and the safety of the diagnoses taken is increased.

OT _

Claims

claims

1. A homogeneous illumination ophthalmological apparatus for observing and / or documenting an eye whose illumination device consists of an illumination source, a homogenization unit and a projection device, wherein one or more spectrally selectively emitting radiation sources (1) on an organic or inorganic basis are used as the illumination source, which, depending on a control unit, generate a continuous and / or pulsed illumination with very high homogeneity, in order to enable via a visualization unit a correspondingly adapted visual and / or digital observation, recording or output of the images of the eye (9).

2. An ophthalmological device according to claim 1, wherein the lighting device consisting of a lighting source, a homogenizing unit and a projection device lighting device additionally has means for geometrical and / or spectral manipulation of the emitted light, which are optionally used.

3. Ophthalmological apparatus according to claim 1 and 2, are used as the spectrally selectively emitting radiation sources LED, SLD, laser or OLED individually or in combination.

4. Ophthalmological device according to at least one of the preceding claims, wherein the illumination device has a plurality of spectrally selectively emitting radiation sources (1) with the same and / or different intensity distributions as a function of wavelength, which are imaged by means of dichroic mirrors on a common aperture.

5. Ophthalmological apparatus according to at least one of the preceding claims, wherein the intensity distribution of the radiation sources (1) are broadband, narrowband or monochromatic or combinations thereof.

6. Ophthalmological device according to at least one of the preceding claims, wherein the radiation source (1) have an optical minimum power and the light radiates locally evenly from the emitting surface.

7. Ophthalmological apparatus according to at least one of the preceding claims, wherein the intensity of the radiation source (1) over a large range continuously adjustable and the color temperature over the entire range of the intensity is largely constant.

8. Ophthalmological device according to at least one of claims 1 to 4, wherein the illumination device for emitting a broadband spectrum of preferably 400 to 700 nm, via one or more radiation sources (1) which emit a monochromatic spectrum of 400 to 490nm and with a Luminescent dye for color conversion are coated.

9. Ophthalmological device according to at least one of claims 1 to 4, wherein the illumination device for emitting a broadband spectrum of preferably 700 to 110Onm, one or more radiation sources (1) having a half-width of at least 20nm and the visual and / or digital Observation, recording or output of a sensitive in this spectral range digital camera unit is present.

10. Ophthalmological device according to at least one of claims 1 to 4, wherein the illumination device for excitation of fluorescence via one or more narrow-band, a monochromatic spectrum emitting radiation source (1) having a half-width of 50nm maximum and a preferably Gaussian course with a central peak ,

11. Ophthalmological apparatus according to at least one of the preceding claims, in which the control unit controls and monitors the time sequence, duration and intensity of the radiation sources (1) individually, jointly or in groups.

12. An ophthalmological device according to at least one of the preceding claims, wherein the homogenization unit present in the illumination device is a light integrator or light mixer arranged in front of the radiation sources (1).

13. An ophthalmological device according to at least one of the preceding claims, wherein the homogenization unit is a hollow integrator (4) or microlens array (3).

14. An ophthalmological device according to at least one of the preceding claims, wherein the control unit determines the optical power and / or the geometry of the light emitted from the radiation sources (1), monitored and corrected to the radiation exposure of the eye (9) so low as possible and within the permitted limits.

15. An ophthalmological device according to at least one of the preceding claims, wherein the digital camera unit is designed so that it can be used as a device for visual observation, wherein the output of the image of the examined eye (9) takes place on a display, which at the Camera or is available separately.

16. An ophthalmological device according to at least one of the preceding claims, wherein the control unit is integrated or formed as a separate, connected via data lines unit.

17. Ophthalmological device according to at least one of the preceding claims, wherein the separately formed control unit via a user terface with an operating unit, a keyboard, a display and a data output unit, wherein as data lines preferably standard PC interfaces are used.

18. An ophthalmological device according to at least one of the preceding claims, wherein the display is designed so that in addition to the visual output of the image of the examined eye (9) also control and adjustment data of the overall system can be displayed.

19. An ophthalmological device according to at least one of the preceding claims, wherein the control unit have means for reducing or switching off the supply of the radiation source (1).

20. An ophthalmological device according to at least one of the preceding claims, wherein a unit of the spectrally selective radiation source (1) consists of a combination of a narrowband emitting semiconductor light source, which is additionally preceded by an optical filter unit to make a further spectral narrowing of the emission.

21. An ophthalmological device according to at least one of the preceding claims, wherein the timing of the duration, duration and intensity of the radiation sources (1) individually, jointly or in groups are controlled and monitored by the compliance of the permissible radiation exposure of the eye (9) guarantee.

22. An ophthalmological device according to at least one of the preceding claims, in which the visualization unit is at least one digital camera unit, a viewing tube with a view or the like.

23. An ophthalmological device according to at least one of the preceding claims, in which an optical image stabilizer is present to reduce fuzziness in the electronic recordings of the eye (9).

24. Ophthalmological apparatus according to at least one of the preceding claims, wherein to avoid blurring in the electronic recordings of the eye (9) by the control unit, the exposure times while increasing the radiation power of the radiation sources (1) can be reduced.

25. An ophthalmological device according to at least one of the preceding claims, wherein for the colinear imaging of a plurality of radiation sources (1) serving as laser sources, an optical grating or a prism is present.

26. An ophthalmological device according to at least one of the preceding claims, in which for the exact simultaneous recording of a plurality of monochromatic images of the eye several image sensors and corresponding dichroic filters or beam splitter filter combinations are present.

27. An ophthalmological device according to at least one of the preceding claims, wherein for the exact simultaneous recording of a plurality of monochromatic images of the eye Foveon ^® X3 ™ image sensors is present.

28. An ophthalmological device according to at least one of the preceding claims, wherein for receiving a plurality of monochromatic images with a very short time offset an electronic camera unit is present, which has interline sensors for buffering a recording.

29. Ophthalmological device according to at least one of the preceding claims, wherein the illumination device designed as a separate unit and for transmitting the generated radiation, a light guide is present.