Visual examination( visual acuity determination) - Causes, symptoms and treatment. MF.

The definition of visual acuity is a definition of the ability of the eye to distinguish between two luminous points located at a minimum distance from each other, expressed by a number. Those.visual acuity is the ability to view the structure of an object. Actually, this method of research allows us to determine the level of vision of the patient, but, unfortunately, this method is not applicable in children under 3-4 years of age.

Any reference to an ophthalmologist is an indication for determining visual acuity. There are no contraindications to this procedure. Distinguish the definition of visual acuity for the distance and for near.

Inspection of vision in the distance

Special tables are used to determine visual acuity. For the distance, these are Sivtsev's tables( with the letters of the Russian alphabet) and Golovin( with Landolt's rings), and for children, Orlova( with pictures).Opposite to each line in these tables is written the visual acuity to which this line corresponds.

This method is not basic, but it is indicative, i.e.he allows you to make the necessary plan for further examination of the patient, so he is among the mandatory and one of the first methods of research in ophthalmology.

For the procedure it is necessary to have a table with Rota's apparatus( a wooden box with an electric lamp), pointers, a flap, a set of test spectacle lenses, and a chair. The patient sits down on the chair located 5 meters from the table and covers the left eye with a scute, while the visual acuity of the right eye is being studied;and then covers the right eye and examines the visual acuity of the left eye. It is necessary to strictly adhere to this order of eye examination.

During the study, it is necessary to keep the head straight, the shield should be placed vertically, you can not cover the closed eye, i.e. Both eyes should be open, you can not also squint, press the flap on the closed eye. The patient should refer to the letters indicated by the doctor, the direction of the cuts of the rings or pictures. Each element must be shown within 2-3 seconds by a pointer, the tip of which must be clearly visible. It must be ensured that the pointer does not close the object. The doctor begins to determine the visual acuity from showing the symbols of the 10th row of the table and gradually moves to the rows with the largest objects. In patients with known reduced visual acuity, a check is made from the top line, showing one object down the line to the row where the patient is wrong, after which it is necessary to return to the previous row. Visual acuity is evaluated by the line in which the patient correctly named all objects. One error is allowed in 3-6 rows, and two errors in 7-10 rows, but this is the doctor marks in the map.

At first, visual acuity is examined without correction, and then with correction, which allows more detailed evaluation of visual function. If the patient uses glasses, the vision is checked without them and in them.

If the patient does not see the first line of the table, the doctor suggests counting the spread fingers of the hand and notes the distance from which the patient can do it. If the patient sees only the movement of the hand in the face and can not count the fingers, then the doctor and writes it in his card. If the patient does not see movement, then they resort to the definition of light perception. To do this, in a darkened room, the eye is illuminated with a bright light beam, and the patient should note whether he sees light and, if seen, from which side. As a rule, the absence of light perception or the wrong projection of light is associated with retinal or optic nerve damage. If the patient's eye is not able to distinguish light from darkness, then he is completely blind.

All the results of the study the doctor enters into the patient's card, where OD means the right eye, OS - the left eye, OU - both eyes. The results are written in the form of a fraction, where the results of the right eye study are recorded from above, and the left eye is recorded from the bottom.

The duration of the procedure with good vision, when there is no need to select the correction is 1-2 minutes. If you need a vision correction, the procedure can take about 20 minutes.

This procedure does not have any complications.

Visual inspection near

Having a high visual acuity in the distance does not mean that it will be high and close. To do this, use a special table, which consists of several texts with different letters.
The patient should keep the table at a distance of 33-34 cm from the eyes. Visual acuity is checked separately for each eye, without correction( or glasses) and with correction, and for eye selection, visual acuity for nears is determined simultaneously for both eyes. The visual acuity for near characterizes the smallest text that a patient can read without errors.

Doctor ophthalmologist Odinochko EA