DE102011106898A1 - Ophthalmic procedure and associated ophthalmic device - Google Patents

Abstract

The present invention relates to an ophthalmological device and ophthalmological method in which disturbing reflections in the image of the eye of the person to be examined are minimized. The object of the invention is achieved by additional polarization filtering of the already polarized light totally reflected by the eye.

Description

The present invention relates to an ophthalmological device and ophthalmic method in which disturbing reflections in the image of the eye of the person to be examined are minimized.

In ophthalmic devices and ophthalmic procedures reflections of light sources can be seen in the image of the eye. As a result, important information about the condition or existing changes in the eye can be outshined, covered and / or changed. In 1 is a schematic representation of the forming reflection of the light source in the eye surface area. An example in work with slit lamps is the use of a line light (light stripe), which illuminates the eye. In this case, for example, by diffraction, refraction, scattering and other optical effects details in the eye outside the light stripe will be visible, but also the light intensity or brightness of the light stripe can bring disturbing and unwanted effects in the investigation with it.

Proceeding from this, it is therefore an object of the invention to develop a device and an associated method which prevents or at least minimizes the mentioned disadvantages of unwanted reflection in the area of the eye surface to be examined.

According to the invention, the object is achieved by polarizing the illumination light of the eye required during the ophthalmological examination. The polarized light is partially totally reflected by the eye and maintains the polarization. In the image it can be seen as a point of light (disturbing reflection). The part of the polarized light that is not totally reflected by the eye is depolarized. A sufficient minimization of the reflection in the image is not given afterwards (see 2 ). The object of the invention is achieved by additional polarization filtering of the polarized light totally reflected by the eye. A schematic embodiment of the invention is in 3 shown. The attenuation of the reflections in the image are achieved by a rotation of the Polfilterstellung each other. The degree of rotation can be variable. In a particularly advantageous manner, a polarization filtering is achieved by a first filter position P1 at almost 0 °, while the filter position of the polarizing filter is almost 90 ° (as in 3 shown). If the polarization filter position of the P1 is not equal to 0 °, an optimum can be achieved by the corresponding polarization filter position of the P2 to be rotated. The filter positions of the polarization filter can differ up to 90 ° from each other, but also other mutually standing positions are possible. Before the light impinges on the imaging unit, conventional optics known to those skilled in the art may be arranged downstream.

The invention also provides a device according to the method of the invention. The device comprises at least one light source (L), arranged in the beam path of the emitted light polarization element (P1), a polarization element (P2), which is arranged so that it can filter out that polarized, totally reflected by the eye light. One embodiment of the device is 3 can be found in the beam path to the imaging unit for conventional optics usual.

An embodiment of the invention is, for example, the reflection minimization of a slit lamp in ophthalmological examination devices.

• – Spaltprojektor mit integriertem, drehbarem linearem Polarisationsfilter, welches das emittierte Licht in einer Ebene linear polarisiert;
• – der Verlust an Helligkeit (ca. 50%) kann durch eine leistungsstärkere Lichtquelle (z. B. neutralweiße High Power LED) kompensiert werden;
• – Reflexion auf der Augenoberfläche (Tränenfilm auf Hornhaut (Cornea) und Bindehaut (Tunica conjunctiva)) → lineare Polarisation bleibt erhalten
• – Rückstreuung im Augeninneren (Regenbogenhaut (Iris), Linse (Lens), Glaskörper (Corpus vitreum) ...) → lineare Polarisation wird durch diffuse Streuung zerstört
• – Spaltlampenmikroskop mit vorgeschaltetem linearzirkularem Polarisationsfilter (linearer Polarisationsfilter mit anschließender λ/4-Verzögerungsschicht)
• – durch Verdrehung der Polarisationsebene der Spaltlampe um 90° zur Polarisationsebene des Spaltlampenmikroskopfilters erfolgt eine nahezu vollständige Auslöschung des von der Augenoberfläche reflektierten Lichtes bei nur geringfügiger Abschwächung der Intensität des diffus reflektierten Lichtes des Augeninneren
• – durch Verdrehung der Polarisationsebene der Spaltlampe um 0° zur Polarisationsebene des Spaltlampenmikroskopfilters bleiben die Reflexe erhalten und können weiterhin zur Untersuchung von Oberflächenunebenheiten genutzt werden
• – die anschließende zirkulare Polarisation verhindert, dass Strahlteiler durch die fresnelschen Formeln beeinträchtigt werden.

Here are

• - Slit projector with integrated, rotatable linear polarization filter, which linearly polarizes the emitted light in a plane;
• - the loss of brightness (about 50%) can be compensated by a more powerful light source (eg neutral white high power LED);
• - Reflection on the surface of the eye (tear film on the cornea and conjunctiva) → linear polarization is maintained
• - Backscatter inside the eye (iris, lens, vitreous (corpus vitreum) ...) → linear polarization is destroyed by diffuse scattering
• - Slit lamp microscope with upstream linear-circular polarization filter (linear polarization filter with subsequent λ / 4 retardation layer)
• - By rotation of the plane of polarization of the slit lamp by 90 ° to the plane of polarization of the slit lamp microscope filter is an almost complete extinction of the light reflected from the ocular surface with only a slight attenuation of the intensity of the diffusely reflected light of the inside of the eye
• - By turning the polarization plane of the slit lamp by 0 ° to the polarization plane of the slit lamp microscope filter the reflections are retained and can continue to be used to investigate surface irregularities
• The subsequent circular polarization prevents beam splitters from being affected by the Fresnel formulas.

• – Umfeldbeleuchtung mit integriertem linearem Polarisationsfilter → emittiertes Licht ist in einer Ebene linear polarisiert;
• – Reflexion auf der Augenoberfläche (Tränenfilm auf Hornhaut (Cornea) und Bindehaut (Tunica conjunctiva)) → lineare Polarisation bleibt erhalten;
• – Rückstreuung auf Regenbogenhaut (Iris) und Bindehaut (Tunica conjunctiva) → lineare Polarisation wird durch diffuse Streuung zerstört;
• – Spaltlampenmikroskop mit vorgeschaltetem, drehbarem linear-zirkularem Polarisationsfilter (linearer Polarisationsfilter mit anschließender λ/4-Verzögerungsschicht);
• – durch Verdrehung der Polarisationsebene am Spaltlampenmikroskop um 90° zur Polarisationsebene der Umfeldbeleuchtung erfolgt eine nahezu vollständige Auslöschung des von der Augenoberfläche reflektierten Lichtes bei nur geringfügiger Abschwächung der Intensität des diffus reflektierten Lichtes des Augeninneren;
• – die anschließende zirkulare Polarisation verhindert, dass Strahlteiler durch die fresnelschen Formeln beeinträchtigt werden.

A further embodiment of the invention provides the reflex minimization of the ambient lighting in ophthalmological examination devices (eg slit lamp).

• - ambient lighting with integrated linear polarization filter → emitted light is linearly polarized in one plane;
• - Reflection on the eye surface (tear film on the cornea and conjunctiva (tunica conjunctiva)) → linear polarization is retained;
• - backscatter on the iris and conjunctiva (→ conjunctiva) → linear polarization is destroyed by diffuse scattering;
• - slit lamp microscope with an upstream, rotatable linear-circular polarization filter (linear polarization filter with subsequent λ / 4-retardation layer);
• - By rotation of the plane of polarization at the slit lamp microscope by 90 ° to the plane of polarization of the ambient illumination is almost complete extinction of the light reflected from the eye surface with only slight attenuation of the intensity of the diffusely reflected light of the inside of the eye;
• The subsequent circular polarization prevents beam splitters from being affected by the Fresnel formulas.

From the 4 It can be seen that there is a clear minimization of reflection in the eye.

LIST OF REFERENCE NUMBERS

1

eye

2

light source

3

Unpolarized light

4

optics

5

imaging unit

6

Polarized light

7

Polarized reflection of the light source

8th

Unpolarized reflection, eg the iris

P1

polarizing filter 1

P2

polarizing filter 2

Claims (5)

Ophthalmological method for minimizing reflections in or on the eye, characterized in that needed in the ophthalmological examination illumination light of the eye is polarized and is then carried out by an additional polarization filtering of the polarized, totally reflected by the eye light. Ophthalmological method for minimizing reflections in or on the eye according to claim 1, characterized in that a rotation of the Polfilterstellung each other is made. Ophthalmological method for minimizing reflections in or on the eye according to claim 1 and 2, characterized in that the filter positions of the polarization filter differ by 90 °. Ophthalmological method for minimizing reflections in or on the eye according to claim 1 to 3, characterized in that the first filter position P1 is set to almost 0 ° and the filter position of the polarization filter P2 to almost 90 °. Ophthalmic device comprising at least one light source (L), arranged in the beam path of the emitted light polarization element (P1), a polarization element (P2), which is arranged so that it can filter out that polarized, totally reflected by the eye light.

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