DE20212917U1 - Arrangement for assessing the fit and condition of contact lenses on the eyes - Google Patents

Description

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Arrangement for assessing the fit and adjustment status of contact lenses on the eyes

The present invention relates to an arrangement with which the fit and adjustment of contact lenses on the eye can be assessed. To do this, fluorescein is introduced into the eye fluid in the usual manner and concentration prior to the examination. Based on the fluorescence patterns generated, conclusions can be drawn about the fit and adjustment of contact lenses.

According to the current state of the art, the fit and adjustment of contact lenses on the eye can be assessed using ophthalmological examination devices such as slit lamps. According to [1], fluorescein is introduced into the tear fluid of the eye to be examined in a suitable concentration. When using fluorescein, light with as high a blue component as possible is required to stimulate the fluorescence effect. The lighting devices of slit lamps therefore usually have a blue filter that can be swiveled in if necessary. The observation contrast can be improved by inserting an additional yellow filter into the observation beam path, which filters out the unwanted illumination light.

The ophthalmological device described in patent US 4,686,981 for the precise positioning of a contact lens on the eye does not use fluorescein. The positioning of the contact lens is controlled using images of the front segments of the eye (pupil) and the contact lens to be fitted. A computing unit uses the exact positions of the pupil and contact lens determined by a detection unit to determine the relative positioning of the pupil and contact lens to one another.

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The technical solutions known from the state of the art for checking the fit and adjustment of a contact lens on the eye have the disadvantage that the equipment is expensive, the device is usually stationary and the necessary adjustment and adaptation of the device to the patient takes a considerable amount of time. After the patient has been placed in front of the device, the device must be positioned on the eye to be examined and the corresponding filters inserted. Only then can the adjustment of the contact lens be checked. With a large number of such examinations (&ogr; using fluorescein), these additional steps add up to a considerable additional time burden.

Literature: [1] Rassow B et al., “Ophthalmological-optical instruments”, 1987, Ferdinand Enke Verlag Stuttgart, p. 99 ff

The present solution is based on the task of developing an arrangement with which a simple and quick check of the fit and adjustment status of contact lenses on the eyes is possible at any time without much preparation.

The problem is solved by the features of the independent claims. Preferred developments and embodiments are the subject of the dependent claims.

Due to the simplicity of the arrangement and its small dimensions, the described arrangement can be used by both ophthalmologists and opticians to assess the fit and adjustment of a contact lens on the eye. No stationary examination stations are required and the described arrangement is compact, lightweight, independent of the mains and portable. In contrast to other devices, it can also be used on a patient lying down.

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The technical solution is described below using an example. This shows:

Figure 1: a schematic representation of the arrangement according to the invention.

The arrangement for assessing the fit and adjustment state of a contact lens 12 on an eye by generating fluorescence effects in conjunction with a fluorescent agent introduced into the tear fluid consists of an illumination device 1 and a

Observation device 2. The illumination device 1 emits light in a very limited wavelength range, which contains an excitation wavelength matched to the fluorescent agent. When using disodium fluorescein as the fluorescent agent, a blue light source such as a light-emitting diode 7 in the range 450 to 480 nm is required.

In an advantageous embodiment, the lighting unit 1 has at least one light-emitting diode 7 and one or more optical elements 8 for beam shaping and achieving a uniform intensity distribution. To achieve a compact form, the light-emitting diode 7 is supplied by a switchable, battery-operated power supply 9, which has control means for brightness control 13 and is located in a common handy housing with the latter.

The observation unit 2 consists of one or more optical components 10 for magnified imaging of the area to be examined (magnifying glass function) and additionally has a blocking filter 3 for suppressing the illumination light. In an advantageous embodiment, the optical component 10 for magnified imaging is simultaneously designed as a blocking filter 3 for the illumination light, for example by achieving the desired effect by coloring the material appropriately. When using disodium fluorescein as a fluorescent agent and a blue light-emitting diode 7, a yellow blocking filter 3 is required. The observation unit 2 and the illumination unit 1 are connected to one another in such a way that the light emitted by the

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optical axes 4 and 5 is variable. Preferably, the optical axes 4 and 5 enclose an angle of approximately 30-40°. The connection 6 between the lighting and observation units 1 and 2 is not fixed, so that on the one hand the included angle and on the other hand the intersection point of the two optical axes 4 and 5 can be varied in order to be able to adjust the distance to the eye 11. Since this is a direct illumination, the intersection point of the two optical axes 4 and 5 is in the eye 11. The illumination is usually from the side in order to be able to observe centrally.

A variation of the angle enclosed by the optical axes 4 and 5 or the distance between their intersection is useful in order to be able to ensure observation under different lighting conditions. However, for a simple design, a fixed connection 6 is also conceivable; by pivoting around the longitudinal axis of the housing, a quick change from right to left is possible. To make the arrangement easier to handle, the common housing can have a handle, preferably a pistol grip.

The assessment of the fit and adjustment of a contact lens 12 on an eye 11 is carried out by evaluating the fluorescence patterns generated. If the fit is good, the distance between the contact lens 12 and the cornea and thus also the tear film in between is the same everywhere. The fluorescent light is evenly distributed with the same brightness over the lens surface. If the fit is poor, the distance between the contact lens 12 and the cornea and thus also the tear film in between is different. The fluorescent light is distributed at different brightness levels. A thinner tear film results in less fluorescence and thus less brightness. Conclusions can be drawn from this about the fit of the contact lens 12.

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With the technical solution presented, an assessment of the fit and adjustment status of a contact lens 12 on an eye 11 is possible quickly and, above all, regardless of location by using a fluorescent agent.

Claims (10)

1. Arrangement for assessing the fit and adjustment state of a contact lens ( 12 ) on an eye ( 11 ), using fluorescence effects in conjunction with a fluorescent agent introduced into the tear fluid, consisting of an illumination device ( 1 ) and an observation device ( 2 ), characterized in that - that the illumination device ( 1 ) emits light with an excitation wavelength matched to the fluorescent agent, - that the lighting device ( 1 ) emits light in a limited wavelength range, - that the observation device ( 2 ) has an additional blocking filter ( 3 ) to suppress the illumination light and - that the illumination device ( 1 ) and the observation device are connected to one another in such a way ( 2 ) that the angle enclosed by the optical axes ( 4 , 5 ) is variable. 2. Arrangement according to claim 1, characterized in - that the connection between the lighting unit ( 1 ) and the observation unit ( 2 ) is designed such that the included angle and thus the distance to the object can be varied. 3. Arrangement according to at least one of the preceding claims, characterized in - that the connection ( 6 ) between the illumination unit ( 1 ) and the observation unit ( 2 ) is designed such that the intersection point of the two optical axes ( 4 , 5 ) can be varied. 4. Arrangement according to at least one of the preceding claims, characterized in - that the lighting unit ( 1 ) has at least one light-emitting diode ( 7 ). 5. Arrangement according to at least one of the preceding claims, characterized in - that the lighting unit ( 1 ) additionally has one or more optical elements ( 8 ) for beam shaping and achieving a uniform intensity distribution. 6. Arrangement according to at least one of the preceding claims, characterized in - that the lighting unit ( 1 ) has a battery-operated, switchable power supply ( 9 ), - that this power supply ( 9 ) has means for brightness control ( 13 ) and - that the power supply ( 9 ) and the means for brightness control ( 13 ) are integrated into the lighting unit ( 1 ). 7. Arrangement according to at least one of the preceding claims, characterized in - that the observation device ( 2 ) has one or more optical components ( 10 ) for magnified imaging of the eye to be examined ( 11 ). 8. Arrangement according to at least one of the preceding claims, characterized in - that the optical component ( 10 ) for the magnified image of the eye to be examined ( 11 ) is simultaneously designed as a blocking filter ( 3 ) for the illumination light. 9. Arrangement according to at least one of the preceding claims, characterized in - that the lighting unit ( 1 ), when using disodium fluorescein as a fluorescent agent, has at least one blue light-emitting diode ( 7 ) with a wavelength suitable for exciting the fluorescence and - that the observation unit ( 2 ), when using disodium fluorescein as a fluorescence agent, has a yellow blocking filter ( 3 ) to increase the contrast. 10. Arrangement according to at least one of the preceding claims, characterized in - that the lighting unit ( 1 ) has a handle, preferably a pistol grip, for easier handling.