RU2793528C1 - Retinal camera for examination of the state of the retina and eye fundus - Google Patents

Abstract

FIELD: ophthalmology.

SUBSTANCE: retinal camera for examination of retina and eye fundus state contains a housing with a replaceable optical nozzle mounted on it, a transmitting lens, a receiving lens and a matrix photodetector device installed in the housing and connected in series. Moreover, a replaceable optical attachment, a transmitting lens, a receiving lens and a matrix photodetector device form an optical system of a retinal camera configured to operate within a field of view angle equal to 50°, or 100°, or 137°. In this case, the replaceable optical attachment includes three lens elements made with spherical surfaces, and the transmitting lens includes four lens elements, two of which are made in the form of gluing.

EFFECT: increasing the efficiency, speed and safety of studies of the state of the retina and eye fundus, as well as simplifying the research process, without complicating the design of the device and without limiting its use.

3 cl, 4 dwg

Description

The field of technology to which the invention belongs

The invention relates to ophthalmology, namely to equipment for studying the state of the retina and the fundus, in particular, to devices that allow obtaining a reliable picture of the state of the retina and fundus, the course of their disease, and allowing timely adjustment of therapy.

State of the art

The prior art cameras for visualization of the fundus, containing an optical system for focusing radiation reflected from the retina, for example, a portable fundus camera (US patent application US 2012/0287255A1, 11/15/2012).

This device works as follows: radiation from sources using an optical fiber (not shown) enters the organ of vision under study, then, reflected from the retina, enters the optical system, passing through which it is focused on a matrix photodetector, the signal from which enters the information processing device . As the organ of vision, a simplified model is used, modeled in the program for calculating optical systems ZEMAX.

The disadvantage of this device is the narrow field of view of the optical system of the camera 2ω, which is 40°. Such an angular field of view of the system does not allow obtaining a complete image of the retina of the examined organ of vision. For such tasks, the values of the angular field of view should be at least 130°. In this device, to obtain a complete picture of the retina, the combination of five images is used, for which it is necessary to move the device along the patient's organ of vision, which will bring discomfort to the procedure. To obtain images of several areas, it is also possible to use the rotating optical elements described in the proposed invention, however, their use will lead to a noticeable complication of the design, increase the cost of the product, and may also cause discomfort due to the noise of the engines during the study. Another way to expand the angular field of view of this device is to introduce a two-mirror Cassegrain system into the optical system, which also complicates the optical system and necessitates additional adjustment of the system. The use of a rotary nozzle for observing the periphery of the retina of the organ of vision will also complicate the design of the product. In addition, to obtain a complete picture of the retina of the patient's organ of vision, it is not enough to "stitch" five images, since the intersection of the fields of view is necessary for the correct connection of the images. It is possible to increase the number of "stitched" images, but this will affect the speed of image processing and displaying it on the monitor screen of a specialist. The disadvantages of the fundus camera should also include the possibility of only contact examinations of the patient's organ of vision, which, of course, introduces discomfort for the patient. The need to conduct non-contact studies will lead to significant changes in the optical system of the product.

The claimed solution eliminates these shortcomings and allows you to achieve the claimed technical result.

Disclosure of invention

The technical problem that the proposed solution solves is the creation of a retinal camera that provides high efficiency, speed, safety and ease of research into the state of the retina and fundus.

The technical result is to increase the efficiency, speed, and safety of studies of the state of the retina and the fundus, as well as to simplify the research process, without complicating the design of the device and without limiting its use.

To solve the problem with the achievement of the claimed technical result, the retinal camera for studying the state of the retina and the fundus contains a housing with a replaceable optical nozzle installed on it, a transmitting lens, a receiving lens and a matrix photodetector device are installed in the housing and connected in series, and a replaceable optical nozzle that transmits the lens, the receiving lens and the matrix photodetector form an optical system of the retinal camera, configured to operate within the field of view angle equal to 50° or 100° or 137°, while the replaceable optical attachment includes three lens elements made with spherical surfaces , and the transmitting lens includes four lens elements, two of which are made in the form of gluing.

In addition, the replaceable optical nozzle is made contact or non-contact.

In addition, the replaceable optical attachment is designed to be used with a minimum distance of 0.2 mm to the organ of vision.

In addition, a light filter is additionally installed between the transmitting and receiving lens.

In addition, the retinal camera is additionally equipped with an autonomous power source.

Brief description of the drawings

Fig.1 - Block diagram of a digital television complex;

Fig.2 - Schematic optical diagram of the retinal camera;

Fig.3 - Diagram of scattering spots in the field of the matrix photodetector when using a wide-field interchangeable optical nozzle with an angular field of view 2ω 137°;

Fig.4 - Distribution of the energy concentration function in the circle of scattering when using a wide-field interchangeable optical nozzle with an angular field of view 2ω 137°.

Implementation of the invention

The retinal camera is usually part of a digital television complex for visualizing the state of the internal surfaces of the eyeball, the surface of the retina, which contains (figure 1) an ophthalmic device - a retinal camera 3 (fundus camera) with a lens 2, into which the image 1 of the fundus falls, a base station 4 connected to the retinal camera 3 via a cable connection or a wireless connection, pedals 5 having the ability to adjust several parameters (adjusting the illumination of the fundus, focusing, etc.).

The claimed retinal camera 3 consists of a housing, lenses interconnected and forming the optical system of the camera, namely, an interchangeable lens (optical attachment) 2, a transmitting lens 6, a receiving lens 7, and a matrix photodetector device 8. The retinal camera can be equipped with an autonomous source nutrition.

In FIG. 2 shows: a replaceable optical attachment 2, which consists of three lens elements made with spherical surfaces, a transmitting lens 6, which includes four lens elements, two of which are made in the form of gluing, a receiving lens 7, including focusing lenses, and a matrix photodetector device 8, the data from which is transmitted to the base station 4. The transmitting lens 6, the receiving lens 7 and the matrix photodetector 8 are installed in the camera body 3 and are not interchangeable.

To form a complete picture of the retina of the studied organ of vision in the proposed implementation example, the replaceable optical nozzle 2 provides the following three options for operating modes: the replaceable wide-field nozzle 2a is used to conduct research within the field of view 2ω of at least 137° with a minimum distance to the organ of vision (0.2 mm) and allows you to fully examine the entire retina of the observed organ of vision without moving it, and without the need to use information obtained from several frames, as in the prototype product, which increases the speed of image processing and displaying it on the monitor screen of a specialist, for more detailed studies optical attachment 2b is proposed, which provides operation in an angular field of view 2ω of at least 100° with a minimum distance to the organ of vision (0.2 mm), as well as a narrow-field attachment 2c, which implements an angular field of view 2ω 50° and allows non-contact measurements at a distance no more than 5 mm to the organ of vision.

The replaceable optical nozzle with a field of view angle of 137° and with a field of view angle of 100° are contact, and the replaceable optical nozzle with a field of view angle of 50° is non-contact, which allows not only contact examinations of the patient's organ of vision, but also non-contact ones, providing versatility of use devices, as well as a complete, versatile, effective, safe and comfortable study for the patient.

The entrance pupil of the proposed product is moved forward beyond the interchangeable optical nozzles. To exclude vignetting during the research, the plane of the entrance pupil of the product must be aligned with the plane of the entrance pupil of the observed organ of vision. Changing the distance from the replaceable nozzle 1 to the organ of vision can lead to cropping of the visual fields.

In the proposed implementation, unlike analogues, optical elements with only spherical surfaces are used, which positively affects both the simplification of the manufacture and operation of optical elements and the design as a whole, and cost characteristics. The manufacturability of optical elements with spherical surfaces is higher. In the proposed embodiment, all optical elements are made of optical glass.

If it is necessary to select a narrow spectral range for research, it is possible to install a light filter between the transmitting and receiving objective.

Replaceable optical nozzles can be designed for arbitrary angles of the fields of view, as well as for various options for removing the surface of the first optical element of the nozzle from the organ of vision.

The device works as follows.

With the help of a light guide located on the interchangeable optical attachment 2, the radiation enters the eyeball through the pupil, where, being reflected from the retina of the organ of vision, it passes through the interchangeable optical attachment 2, which forms an image of the retina of the organ of vision for the transmitting lens 6, passing through which it enters the receiving lens. lens 7, which forms an image on the sensitive area of the matrix photodetector 8. Processing and analysis of the resulting image are carried out at the base station 4 and, after processing, a PC built into the base station 4 or located at a distance, is transmitted to the monitor screen for subsequent study and processing by the operator.

Figures 3 and 4 display the results of the tests of the proposed device, namely, figure 3 shows a diagram of scattering spots over the field of a matrix photodetector device when using a wide-field replaceable optical nozzle (2a), and figure 4 shows the distribution of the energy concentration function in the circle of scattering when using a wide-field interchangeable optical attachment (2a).

In the course of laboratory tests of the claimed device, studies of the retina of the patient's organ of vision were carried out.

The patient was examined using a retinal camera made in accordance with the claimed invention, which consisted of a transmitting lens, a receiving lens, a matrix photodetector and an interchangeable contact lens (optical attachment) with a field of view angle of 137° with a minimum distance to the organ of vision (0. 2 mm). The contact lens was equipped with a light guide for illuminating the interior of the eye, which has a white spectrum with a wavelength that excludes the appearance of a blue component in the 460 nm range. With the help of a light guide located on a replaceable optical attachment, the radiation through the pupil entered the eyeball, where, reflected from the retina of the organ of vision, it passed through a replaceable optical attachment, which formed an image of the retina of the organ of vision for the transmitting lens, passing through which it fell on the receiving lens, which already, in turn, formed an image on the sensitive area of the matrix photodetector. Next, the processing and analysis of the received image was carried out at the base station and, after processing, the PC built into the base station was transferred to the monitor screen for subsequent study and processing by the operator. As a result of tests using an interchangeable contact lens with a field of view angle of 137°, it was possible to quickly and safely obtain a clear image of the vascular network of the patient's fundus and made it possible to fully examine the entire retina of the observed organ of vision without moving it, without the need to use information obtained from several frames.

For more detailed studies, an optical attachment with a field of view angle of 100° was installed on the retinal camera, consisting of a transmitting lens, a receiving lens, and a matrix photodetector, instead of an optical attachment with a field of view of 137°. The nozzle was also equipped with a light guide for illuminating the interior of the eye, which has a white spectrum with a wavelength that excludes the appearance of a blue component in the range of 500 nm. With the help of a light guide located on a replaceable optical attachment, the radiation through the pupil entered the eyeball, where, reflected from the retina of the organ of vision, it passed through a replaceable optical attachment, which formed an image of the retina of the organ of vision for the transmitting lens, passing through which it fell on the receiving lens, which already, in turn, formed an image on the sensitive area of the matrix photodetector. Next, the processing and analysis of the received image was carried out at the base station, and after processing the PC built into the base station, it was transferred to the monitor screen for subsequent study and processing by the operator. As a result of tests using an interchangeable contact lens with a field of view of 100°, with a minimum distance to the organ of vision, it was possible to quickly and safely obtain a clear, more detailed image of the patient's fundus vasculature.

For more detailed studies, a retinal camera consisting of a transmitting lens, a receiving lens, and a matrix photodetector device was equipped with an optical non-contact nozzle with a field of view angle of 50° instead of an optical attachment with a field of view of 100°. The nozzle was also equipped with a light guide for illuminating the interior of the eye, which has a white spectrum with a wavelength that excludes the appearance of a blue component in the 480 nm range. With the help of a light guide located on a replaceable optical attachment, the radiation through the pupil entered the eyeball, where, reflected from the retina of the organ of vision, it passed through a replaceable optical attachment, which formed an image of the retina of the organ of vision for the transmitting lens, passing through which it fell on the receiving lens, which already, in turn, formed an image on the sensitive area of the matrix photodetector. Next, the processing and analysis of the received image was carried out at the base station, and after processing the PC built into the base station, it was transferred to the monitor screen for subsequent study and processing by the operator. As a result of tests using an interchangeable non-contact lens with a field of view angle of 50°, it was possible to quickly and safely make non-contact measurements at a distance of no more than 5 mm to the organ of vision, while it was possible to quickly obtain a clear, most detailed image of the vascular network of the fundus.

As shown by the tests, in contrast to the analogue of the claimed device allows you to conduct research both contact, in the case of using a wide-field optical attachment, and non-contact, for a portrait optical attachment. A wide range of interchangeable optical attachments allows you to get a complete reliable picture of the studied organs of vision, the course of their disease, and adjust therapy in time. The design of the optical system of the retinal camera and its ability to work with the above angles of the fields of view provide high efficiency of the study, increase the speed and safety of studies, simplify the study process and reduce discomfort for the patient, without complicating the design of the device and without limiting its use. The simplicity of the design of the optical system eliminates the need for additional adjustment of the system.

Claims (4)

1. A retinal camera for studying the state of the retina and the fundus, characterized in that it contains a housing with a replaceable optical nozzle mounted on it, installed in the housing and connected in series with a transmitting lens, a receiving lens and a matrix photodetector device, and a replaceable optical nozzle, a transmitting lens, the receiving lens and the matrix photodetector form an optical system of the retinal camera, configured to operate within a field of view angle of 50°, or 100°, or 137°, while the replaceable optical attachment includes three lens elements made with spherical surfaces, and the transmitting lens includes four lens elements, two of which are made in the form of gluing. 2. The retinal camera according to claim 1, characterized in that the replaceable optical nozzle, which ensures the operation of the retinal camera within the angle of view of 137° or 100°, is a contact, and the replaceable nozzle, which ensures the operation of the retinal camera within the angle of view of 50° , is contactless. 3. The retinal camera according to claim 1, characterized in that the replaceable optical attachment, which ensures the operation of the retinal camera within the field of view angle of 137° or 100°, is made with the possibility of their use with a minimum distance of 0.2 mm to the organ of vision, and the replaceable the nozzle, which ensures the operation of the retinal camera within the field of view angle of 50°, is made with the possibility of its use at a distance of not more than 5 mm to the organ of vision. 4. Retinal camera according to claim 1, characterized in that a light filter is additionally installed between the transmitting and receiving lenses.

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