Ophthalmoscopy

Ophthalmoscopy is a method of examining the retina, optic nerve and vascular membrane in the rays of light reflected from the fundus. The clinic uses two methods of ophthalmoscopy - in the reverse and in a direct form. Ophthalmoscopy is more convenient for a wide pupil.

The pupil is not dilated if it is suspected of glaucoma, so as not to cause an attack of increased intraocular pressure, as well as atrophy of the pupil sphincter, since in this case the pupil will always remain wide.

Ophthalmoscopy in reverse

It is designed for rapid examination of all parts of the fundus. It is held in a darkened room - a viewing room. The light source is placed on the left and somewhat behind the patient. The oculist is located in front of the patient, holding in his right hand an ophthalmoscope attached to his right eye, and sends a light beam to the eye being examined. An ophthalmic lens with a force of +13.0 or +20.0 D, which the doctor holds with the thumb and forefinger of the left hand, he sets the front eye to a distance equal to the focal length of the lens - 7-8 or 5 cm, respectively. This remains open and looks in the direction past the doctor's right eye. The rays reflected from the patient's fundus come to the lens, are refracted on its surface and form on the physician's side in front of the lens, at its focal length (7-8 or 5 cm, respectively) hanging in the air is real, but increased 4-6 times and an inverted image of the investigated sections of the fundus. Everything that appears to be lying at the top, actually corresponds to the lower part of the investigated area, and what is outside corresponds to the inner parts of the fundus.

In recent years, asphyxial lenses have been used for ophthalmoscopy, which makes it possible to obtain an almost uniform and highly illuminated image throughout the field of view. In this case, the image dimensions depend on the optical power of the lens used and the refraction of the eye: the greater the lens power, the greater the increase and the smaller the visible portion of the fundus, and the increase in the case of using the same lens force in the investigation of the hyperopic eye will be greater than when study of the myopic eye (due to the different length of the eyeball).

Ophthalmoscopy in its direct form

Allows you to directly consider the details of the fundus revealed by ophthalmoscopy in the opposite form. This method can be compared with the examination of objects through a magnifying glass. The study is performed with the help of mono- or binocular electric ophthalmoscopes of various models and designs that make it possible to see the fundus in a direct view enlarged 13-16 times. In this case, the doctor moves as close as possible to the eye of the patient and examines the fundus through the pupil (preferably against the background of medial mydriasis): the right eye of the patient's right eye, and the left eye - the left one.

With any method of ophthalmoscopy, the examination of the fundus is carried out in a certain sequence: first examine the optic nerve disk , then - the area of the macula (macular area), and then - the peripheral parts of the retina.

When examining the optic disc in reverse, the patient should look past the doctor's right ear, if the right eye is examined, and on the researcher's left ear, if examining the left eye. Normally, the optic nerve disk is round or slightly oval in shape, yellowish pink with clear boundaries at the retina level. Because of intensive blood supply, the inner half of the optic nerve disc has a more saturated color. In the center of the disc there is a depression (physiological excavation), this is the place of inflection of the optic nerve fibers from the retina to the trellis plate.

A central retinal artery enters the central part of the disc and a central retinal vein emerges. The central artery of the retina in the region of the optic disc is divided into two branches - the upper and lower branches, each of which in turn is divided into the temporal and nasal. The veins completely repeat the course of the arteries. The ratio of diameter of arteries and veins in the respective trunks is 2: 3. The veins are always wider and darker than the arteries. With an ophthalmoscope around the artery, a light reflex is visible.

Outside the optic nerve, at a distance of two disc diameters from it, there is a yellow spot, or a macular area (anatomical region of central vision). The doctor sees it when researching, when the patient looks directly into the ophthalmoscope. The yellow spot has the appearance of a horizontally located oval, slightly darker than the retina. In young people, this part of the retina is bordered by a light strip - a macular reflex. The foveal reflex corresponds to the central fovea of the yellow spot, which has an even darker color. The picture of the fundus in different people differs in color and pattern, which is determined by the saturation of the retinal epithelium with pigment and melanin content in the choroid. With direct ophthalmoscopy there are no light reflections of the reflections from the retina, which facilitates the study. In the head of the ophthalmoscope, there is a set of optical lenses, allowing you to clearly focus the image.

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Ophthalmochromoscopy

The technique was developed by Professor AM Vodovozov in the 1960s-1980s. The research is carried out with the help of a special electric ophthalmoscope, in which light filters are placed, allowing to examine the fundus in purple, blue, yellow, green and orange light. Ophthalmoscopy is similar to ophthalmoscopy in its direct form, it greatly expands the physician's abilities in establishing the diagnosis, allows you to see the most initial changes in the eye, which are not distinguishable in normal illumination. For example, in the red light, the central region of the retina is clearly visible, and in the yellow-green, fine hemorrhages clearly appear.