SU1377018A1 - Apparatus for examining periphery of fundus of the eye - Google Patents

Abstract

The invention relates to an attached medical device, more specifically to ophthalmic diagnostic devices. The purpose of the invention is to increase the diagnostic capabilities of the device by expanding the field of observation with a prism-lens object and an annular illumination channel. To do this, use a device that contains a lighting system with an illuminator and a fiber light guide and an observation system with a lens, a measuring grid, an eyepiece and an aperture diaphragm installed in series with a lens made in the form of a block of deflecting elements with a brush with identical prisms around the ring . 1 hp f-ly, 3 ill.

Description

WITH

The invention relates to medical technology, namely to ophthalmic diastotic devices.

1The invention is to increase the diagnostic capabilities of 11ribo1) and for the het-rasne Ireni field nab; field;) and with the help of a physics-lens object and an annular illumination channel.

FIG. 1 shows the lighting channel of the device. for examining the fundus nephritis, in two projections; in fig. 2 is an optical diagram of a surveillance system; in fig. 3 - lens unit in two projections.

The device includes an illumination system with a fiber illumination channel, having a ring shape and formed by a multicore fiber light guide 1, the end ends of which are arranged on the ring 2 with an inner diameter slightly exceeding the diameter of the cornea 3 g of the eye, and the illuminator 4. In addition, the device includes a surveillance system comprising an objective lens 5, an eyepiece 6, a diaphragm 7, and a measuring grid 8 mounted for movement along the optical axis of the observation system. The lens is made in the form of a block of identical holes. 9, arranged around the ring, in the bases of which positive lenses 10 are installed, and in the center of the block one positive lens 11 is mounted. Moreover, in the lens a block can be composed of, for example, rectangular 30 ° Nrizm 9, and HiecTb and optic lenses 10 are installed close to the face, lying against an angle of 30 °. Each prism, changing the course of the rays on 60 °, has two reflecting | ranks 12 and 13, angle between which is 30 °. Face 12, opposite the angle of 60 °, and has a mirror cover. The prisms are arranged so that the ribs 14 of 30-degree angles form an equilateral hexagon facing the patient, the reflecting faces 12 form a hexagonal cyrism with axis A-A parallel to the reflecting face 12, which is the axis of the observation system, and the face 13 is a truncated hexagonal pyramid, facing a large base towards the patient. In the hole corresponding to the smaller base of the truncated pyramid, a central positive lens 11 is installed, the focal distance of which is equal to the focal length of the lenses 10. The distance a from the plane of the entrance pupil to the edge of the prism facing the eye being examined is 2.9 m, and the height i of the prism is 17.3 mm with a radius of mm.

The device works as follows.

On the sclera of the examined eye impose a ring 2 of the optical fiber 1, connected to the illuminator 4, which is illuminated.

B

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protects the annular peripheral zone of the fundus to the lumen - diascreral. Due to this, as well as the absence of Coptic with the cornea, the cornea remains open for beams coming out of the gas, which makes it possible to fully utilize the luminosity of the observation system, ensures the complete elimination of corneal reflexes that make it difficult to study the ocular dps. and the peripheral fundus area under investigation is illuminated brightly and evenly. Part of the light flux, scattered by the illuminated area of the sclera inside the eye block, falls on its opposite surface, illuminating also the posterior pole region 15. Observation system 2 is brought to the eye under examination, aligning the entrance pupil with the pupil of the eye, and axis A-AJ of the system observation - with the axis of the eye.

Beams of light coming from the ring 2 of the light guide 1 of the peripheral fundus of the fundus of the eye enter the observation system. Since the angle cx between the middle part of the peripheral zone of the eye bottom and the axis of the eye block for the average eye has a value of about 60 °, and the distance a is 2.9 mm, the beam of rays reflected from the middle part of the peripheral fundus of the eye bottom t from the eye 10 ° angular. 60 ° to its axis and fall on the face 13 of the prism 9 normally to the surface, pass without refraction into the prism and fall on the reflecting face 12. Reflected from the face, these rays fall on the reflecting face 13 of the node with an angle of 60 ° to normal5 li. Since this angle exceeds the total internal reflection angle of the glass of the prism 9, the rays undergo total internal reflection, as a result of which they deviate by 60 ° from the original direction and exit from the prism parallel to it

 reflecting face 12 and axis AA. surveillance systems. Because of this, beams of rays that emerge from the eye at such large angles, so that they cannot be covered by a conventional, even wide-angle lens,

5 is fully covered by the observation system and forms an intermediate image of the extreme peripheral fundus zone.

The location of the entrance pupil of the observation system in the front focal plane of lens 5 achieves a telecentric beam path, which ensures the same image scale for eyes with different degrees of ametropia. In the case of an emmitropic eye, each lens 10 focuses the beams of rays in its rear focal plane, forming an image of the peripheral portion of the optic dpa under study with transverse magnification

0

R . Whole annular prism block 9 with lenses

10 forms in the rear focal plane of the lenses 10 an image of six adjacent peripheral fundus sites along a ring, the center of which lies on the axis A-A of the observation system. Central lens

11 forms, in the same plane in the central part of the annular image of the periphery of the fundus, an image of a section of the fundus with an angular value of about 20 °, adjacent to the posterior pole of the eye, with the same lateral magnification as the peripheral zone. The image of the peripheral and central areas of the fundus of the eye is examined in an eye of 6. Since the grid is installed in the plane of the image of the fundus (in the front focal plane of the eye of eye 6), the doctor simultaneously sees the screen and counts the number of divisions in which fit the fundus element under investigation. By knowing the increase / observation system, the physician thus evaluates the magnitude of the element being investigated. In the case of ametropia of the studied city, the plane of the image of the fundus shifts — for the nearsighted eye it approaches the lens, for the far-sighted — it moves away from it. Therefore, focusing on a sharp image of the fundus of the eye is accomplished by focusing the ocular 6, which, together with the grid 8, is moved along the axis, of the observation system until the grid 8 is aligned with the plane of the fundus image.

This way, the device provides a study of the extreme peripheral

the fundus of the fundus to the dentate line without contact with the cornea, with the simultaneous study of the zone, which is angular in size to the posterior pole of the eye

20 °, as well as localization of changes in the fundus and size estimation with .viaciuTa-bom, the same for eyes with different degrees of ametropia.

Instead of visual observation in the eye 1 p 6 due to the fact that in the back focal plane of the lens 5 a real image of the peripheral and central zones of the fundus is formed, photographing of these zones can be carried out, for which the grid 8, the eyebrow and the aperture 7 must be replaced by a camera.

Claims (2)

Invention Formula 1- A device for examining the periphery of the fundus of the eye, including a lighting system with a fiber illumination channel and a surveillance system comprising a lens, characterized in that in order to increase the diagnostic capabilities of the device by expanding the field of observation, the lens is made in the form of a block of identical prisms located around the ring, at the bases and at the center of the block there are positive lenses, and the lighting channel has a ring shape. 2. The device according to claim 1, wherein:. that it is equipped with a measuring grid mounted for movement along the optical axis of the observation system. J 1 15 5 9 3 u (fJuz.Z 14 / J 12 3 JO ten Fig.Z