DE102020131814A1 - Leak detection device - Google Patents

Abstract

Described is an ophthalmoscope for examining the posterior eye sections of a patient's eye with an illumination device for generating at least one illumination beam, illumination imaging optics for imaging the illumination beam onto the patient's eye, a means for scanning the illumination beam (BL) over the patient's eye, an observation device, an observation Imaging optics for imaging an observation beam generated by reflection of the illumination beam on the patient's eye onto the observation device, and a means for masking out scattered light from the observation beam.
The invention is characterized in that a glass plate which can be tilted relative to the illumination beam and through which the illumination beam passes is arranged along the illumination beam.

Description

technical field

The invention relates to an ophthalmoscope for examining the posterior sections of a patient's eye, having an illumination device for generating at least one illumination beam, illumination imaging optics for imaging the illumination beam onto the patient's eye, a means for scanning the illumination beam (BL) over the patient's eye, an observation device, an observation imaging optics for imaging an observation beam generated by reflection of the illumination beam at the patient's eye onto the observation device, and a means for hiding scattered light from the observation beam.

State of the art

For a reliable examination of the posterior sections of the eye, especially the fundus, an ophthalmoscope is used, which is able to produce an image of the retina with as little reflection as possible and with which pathological changes in the fundus of the eye, such as retinal detachments, retinal hemorrhages or changes in the retinal vessels can be examined.

The disadvantage of conventional ophthalmoscopes lies in the continuous illumination of the fundus and a poorly contrasted fundus image caused by scattered light and associated therewith. So-called scanning systems, with which only a small area of the fundus of the eye is illuminated and observed at the same time through oscillatingly mounted slit-shaped diaphragms in the observation beam path and in the illumination beam path, offer significant advantages with regard to improved image quality. In order to still be able to examine a larger part of the fundus, the illumination diaphragm and the observation diaphragm are moved synchronously, whereby a part of the fundus is actually scanned. If the ocular fundus is observed with a detector that has a certain inertia and the slit images of the diaphragms move quickly enough over the same part of the ocular fundus, then the individual images merge into an overall image of the scanned part of the ocular fundus. Such scanning ophthalmoscopes enable the fundus of the eye to be viewed, in particular when the lens of the eye is already clouded, by reducing the generation and observation of scattered light and the resulting glare. In this case, a real intermediate image is generated outside the eye by means of an ophthalmoscopy lens in front of the retina, with the illumination device and the magnifying optical system of the ophthalmoscope being focused on the plane of this intermediate image. Such an ophthalmoscope is in EP 1 389 943 B1 described. The known ophthalmoscope has at least one illumination device that generates an illumination beam and imaging optics that can be assigned to the illumination device and that images the illumination beam onto the fundus of the patient's eye via an intermediate image plane. The ophthalmoscope also has at least one observation device and imaging optics which can be assigned to the observation device and which images an observation beam generated by reflection of the illumination beam at the fundus of the eye via the intermediate image plane into the observation device. Finally, a diaphragm arrangement is provided in the illumination and observation beam, each with at least one diaphragm slit that can be introduced into the illumination beam and observation beam, which is mounted so that it oscillates synchronously relative to the illumination beam and observation beam. Such an ophthalmoscope arrangement is also referred to as a scanning ophthalmoscope due to the oscillating diaphragm arrangement that is introduced within the observation and illumination beam path.

Presentation of the invention

Based on the prior art mentioned above, there is still a desire to further reduce or even completely eliminate the residual reflections in the observation beam path in the fundus image representation that are perceived as disturbing. In particular for therapy measures required at the fundus of the eye, such as carrying out local coagulations on the retina using a therapy laser, the attending physician must have an unhindered and largely reflection-free view of the retina at the fundus of the eye.

The solution to the problem on which the invention is based is specified in claim 1. Features that advantageously develop the idea of the invention are the subject matter of the subclaims and the further description, in particular with reference to the explanation of the exemplary embodiments.

According to the solution, an ophthalmoscope according to the features of the preamble of claim 1 is designed in such a way that a glass plate which can be tilted relative to the illuminating beam and through which the illuminating beam transmits or passes is arranged along the illuminating beam.

By preferably manual, controlled tilting of the glass plate relative to the illumination beam path, the illumination beam path is spatially deflected in its further course. Without the presence of a glass plate, as hitherto was the case with known ophthalmoscopes, or with orthogonal orientation of the planar glass plate, the illumination beam runs parallel to the observation beam within a beam path section in the ophthalmoscope. By tilting the glass plate, the illumination beam no longer runs parallel to the observation beam within the beam path section, but encloses an angle α ≠ 0° ≦ 45° to the observation beam that depends on the degree of tilting, so that as a result not all the light of the illumination beam passes through the means for blanking of scattered light from the observation beam, which is preferably designed in the form of an oscillating or rotating mounted slit diaphragm arrangement. The loss of brightness in the observation beam caused by maximum tilting of the glass plate corresponds to about 35%. In addition, the tilting of the glass plate to eliminate the reflex depends on the respective ametropia of the patient's eye, which corresponds to an ametropia of +11 dpt at a maximum tilt, as mentioned above.

Due to the dependency between the ametropia of a patient's eye and the tilting of the glass plate, a preferred embodiment of the ophthalmoscope provides a mechanically positively coupled adjustment of the ametropia with the manually adjustable tilting of the glass plate. In this way, simplified handling becomes possible, in particular when recording the image of the fundus of the eye. The higher the ametropia is in the plus diopter range, the stronger the central reflex that is caused by the ophthalmoscopy lens. This reflex can be eliminated by continuously adjusting the glass plate. In order to minimize the loss of brightness due to the position of the glass plate, the tilted position of the glass plate is preferably coupled with the diopter setting of the ametropia.

In a further preferred embodiment, an infrared color filter is introduced along the illumination beam, which preferably, as the following description will show with reference to the illustrated embodiment, in the optical path of the illumination beam immediately before or after the means for scanning the illumination beam, which is in the form an oscillatingly mounted aperture is formed, is arranged. The gap width of the oscillatingly mounted gap can preferably be variably adjusted via a manually operated adjustment means from a narrow gap to a gap with a maximum gap width. The IR filter puts a strain on the patient's eyes to protect it from light, but it is nevertheless ensured that a user, using the observation device, which is preferably designed as a stereo microscope or stereo tube, receives enough visible light to completely display and reproduce the fundus area for examination and observation.

In particular, in combination with a camera recording the fundus image, whose light sensitivity can be adapted to the infrared wavelength range and whose associated camera view beam path can be coupled into the observation beam path via suitable, loss-free deflection elements, the image of the entire retina can be recorded almost loss-free.

A further embodiment of the ophthalmoscope designed according to the solution provides for the arrangement of a filter unit that reduces the blue light portion of the wavelength spectrum, abbreviated as a blue light filter, along the illumination beam.

For technical reasons, LED lamps cannot produce “white” light. Therefore, there is a mixture of yellowish and blue light components that the human eye perceives as white light. However, blue light is high-energy light that can negatively affect light-sensitive, biological structures such as the retina of the eye, so-called phototoxicity. The proposed blue light filter serves to reduce the amount of blue light reaching the eye.

A specific embodiment of the ophthalmoscope designed according to the solution is explained with reference to the following figure without restricting the general idea of the invention.

character list

• 1 Gesamtdarstellung des Ophthalmoskops,
• 2 Schwenkanordnung der Glasplatte sowie
• 3 Querschnittsdarstellung durch einen Abschnitt des Beleuchtungs- und Beobachtungsstrahlenganges.

The invention is described below by way of example, without restricting the general inventive concept, using exemplary embodiments with reference to the drawings. Show it:

• 1 Overall view of the ophthalmoscope,
• 2 Pivoting arrangement of the glass plate as well
• 3 Cross-sectional view through a section of the illumination and observation beam path.

Ways of carrying out the invention, industrial applicability

In 1 a preferred embodiment of an ophthalmoscope designed according to the solution is shown in a schematic overview with optically relevant components.

An illumination device 2, preferably designed as a white light source, generates the so-called illumination beam BL, which is imaged in a first intermediate image plane Z1 with the aid of condenser optics 6. In the exemplary embodiment shown, an infrared filter 10 is mounted in front of the intermediate image plane Z1 in the beam direction, which is able to block wavelengths of less than 550 nm.

In the intermediate image plane Z1 along the illumination beam path BL, there is an aperture slit 3', the width of which can be varied manually using a rotary knob D. In addition, a possibility is created to manually adjust the horizontal position of the diaphragm gap 3'. The aperture slit periodically oscillates from top to bottom and back again, swinging out of the field of view to block out an increased amount of light at the turning point.

The illumination beam BL imaged in the first intermediate image plane Z1 is imaged to infinity with the aid of an illumination lens 7 and imaged in the beam path via an imaging lens 8 in a second intermediate image plane Z2.

The illumination beam BL is imaged with the aid of an ophthalmoscopy lens unit 9 onto the fundus of a patient's eye 1, at which the illumination beam BL is reflected in the form of an observation beam BO. The observation beam BO is also sharply imaged via the ophthalmoscopic lens unit 9 in the second intermediate image plane Z2, from which the observation beam BO is imaged via the imaging lens 8 to infinity. With the help of an observation lens 12 following in the observation beam path BO, the observation beam BO, which is imaged to infinity, is imaged in the first intermediate image plane Z1, from which imaging optics 13 project the observation beam BO from the first intermediate image plane Z1 into the observation device designed as a stereo tube or stereo microscope 4 depicts.

For the purpose of reducing or eliminating reflections, a tiltable glass plate 5 is arranged in the illumination beam path BL following the imaging lens 8, which when tilted causes an angular change Δα of the beam paths, which otherwise run parallel to one another, relating to the observation beam BO and the illumination beam BL within the beam path section between the imaging lens 8 and the ophthalmoscopic lens unit 9. Without a tilted glass plate 5, the beam paths BL and BO run in such a way that the illumination slit 3', which is created when the illumination beam BL passes through the slit arrangement located in the first intermediate image plane Z1, enters the observation slit of the scanning diaphragm arrangement 3 located in the first intermediate image plane Z1 along the Observation beam path BO is mapped and moved up and down together. By tilting the glass plate 5 and a resulting change in position of the illumination beam BL after passing through the glass plate 5, the illumination slit is also no longer imaged exactly in the observation slit in the first intermediate image plane Z1 along the observation beam BO. For this purpose, within the first intermediate image plane Z1 along the observation beam BO there is a means 3 mounted in a scanning manner for masking out scattered light from the observation beam BO, preferably in the form of an oscillatingly mounted diaphragm arrangement.

In 2 a mounting of the glass plate 5 is shown in a view along the illumination beam BL. For the sake of clarity, it should be mentioned that the observation beam BO comprises two partial observation beams, which result from the use of a binocular stereo microscope arrangement as the observation device 4 .

The glass plate 5 is held in a glass plate holder 13 which is mounted such that it can tilt about the pivot axis 14 . With the help of two manually operated rocker arms 15, which are attached to the left and right of the ophthalmoscope housing (not shown), the glass plate 5 can be moved from a vertical position, in which the illumination beam BL does not deviate in position and passes the glass plate orthogonally, steplessly or in definable stages into a maximum tilt position, in which the glass plate is inclined at 55° to the horizontal.

The glass plate 5 has two flat opposite glass plate surfaces, which are preferably coated with an anti-reflection layer. The glass plate 5 typically has a glass plate thickness of 1 to 5 mm, preferably 3 mm.

In addition, the ophthalmoscope designed according to the solution has, in a preferred further embodiment, see 1 a blue filter 11 on, to suppress blue light with wavelengths < 430 nm.

A further embodiment provides for the use of a fundus camera 16, whose associated camera beam path KL is guided through the scanning diaphragm arrangement 3 to reduce the scattered light components, subsequent deflection optics, consisting of at least two deflection prisms 17 and an observation lens 18 for the purpose of coupling the camera beam path KL coaxially to the Observation beam path BO is coupled.

3 shows a cross section through the beam paths in the area of the intermediate image plane Z1. Thus, in the intermediate image plane Z1, the means 3' for scanning the illumination beam BL is designed and positioned in the form of a diaphragm arrangement whose slit diaphragm width can be variably adjusted. In addition, the horizontal position of the screen assembly is adjustable.

Due to the binocular observation device 4, for example in the form of a stereo microscope, the observation beam consists of two partial observation beams, one for the right and one for the left eye. The camera beam path KL is located in the middle between the two partial observation beams.

Reference List

1

patient eye

2

lighting device

3

Means for scanning the illumination beam path

3'

Means for removing stray light from the observation beam

4

Observation device, stereo tube

5

glass plate

6

condenser optics

7

lighting lens

8th

imaging lens

9

Ophthalmoscopy lens unit

10

IR filter

11

UV filter

12

observation lens

13

glass plate holder

14

pivot axis

15

operating lever

16

camera

17

deflection prism

18

observation lens

BO

observation beam

BL

illumination beam

D

knob

cl

camera beam path

Z1

first intermediate image level

Z2

second intermediate image plane

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 1389943 B1 [0003]

Claims (14)

Ophthalmoscope for examining posterior sections of a patient's eye (1) with an illumination device (2) for generating at least one illumination beam (BL); an illumination imaging optics for imaging the illumination beam (BL) onto the patient's eye (1), a means (3) for scanning the illumination beam (BL) over the patient's eye (1), an observation device (4); observation imaging optics for imaging an observation beam (BO) generated by reflection of the illumination beam (BL) on the patient's eye (1) onto the observation device (4), and a means (3') for hiding scattered light from the observation beam, characterized in that a glass plate (5) which can be tilted relative to the illumination beam (BL) and through which the illumination beam (BL) passes is arranged along the illumination beam (BL). ophthalmoscope after claim 1 , characterized in that the glass plate (5) is tiltable via a manual operating mechanism. ophthalmoscope after claim 1 or 2 , characterized in that the illumination imaging optics have at least one condenser optics (6) imaging the illumination beam (BL) emerging from the illumination device (2) into a first intermediate image plane (Z1), an illumination lens (7) which has the first intermediate image plane (Z1) in the infinity, an imaging objective (8), which images the illumination beam (BL) imaged to infinity in a second intermediate image plane (Z2), from which the illumination beam (BL) can be imaged onto the fundus of the patient's eye (1) via an ophthalmoscopic lens unit (9). , Includes, and that the tiltable glass plate (5) between the imaging lens (8) and the ophthalmoscopic lens unit (9) or between the illumination lens (7) and the imaging lens (8) is arranged. Ophthalmoscope according to one of Claims 1 until 3 , characterized in that the glass plate (5) has a plate thickness d for which 1≦d≦5 mm, preferably d=3 mm. Ophthalmoscope according to one of Claims 1 until 4 , characterized in that the glass plate (5) is surface-coated with an anti-reflection layer. Ophthalmoscope according to one of claims 2 until 5 , characterized in that the manual actuating mechanism for tilting the glass plate is positively coupled to an adjustment unit for adaptation to the ametropia of the patient's eye to be examined. Ophthalmoscope according to one of Claims 1 until 5 , characterized in that an IR color filter (10) is introduced along the illumination beam (BL). ophthalmoscope after claim 7 , characterized in that the IR color filter (10) blocks wavelengths with a wavelength of less than 550 nm. ophthalmoscope after claim 3 such as claim 7 or 8th , characterized in that the IR color filter (10) is arranged between the condenser optics (6) and the first intermediate image plane (Z1). Ophthalmoscope according to one of Claims 1 until 9 , characterized in that a blue light filter for reducing wavelengths of less than 430 nm is arranged along the illumination beam (BL). ophthalmoscope after claim 2 and 10 , characterized in that the blue light filter (11) is arranged between the illumination lens (7) and the imaging lens (8). Ophthalmoscope according to one of claims 2 until 11 , characterized in that the observation imaging optics at least the ophthalmoscopic lens unit (9) imaging the illumination beam (BL) reflected at the eye fundus in the form of the observation beam (BO) in the second intermediate image plane (Z2), the imaging objective (8) which guides the observation beam (BO ) from the second intermediate image plane (Z2) to infinity, an observation objective (12), which images the observation beam (BO) imaged to infinity in the first intermediate image plane (Z1), and imaging optics (13), which reproduce the observation beam (BO) from the first intermediate image plane (Z1) in the observation device (4) includes. Ophthalmoscope according to one of Claims 1 until 12 , characterized in that the lighting device is a white light source or an IR LED. Ophthalmoscope according to one of Claims 1 until 13 , characterized in that the observation device is a stereo tube.

Images