Check sight ( visual acuity ) - Causes, Symptoms and Treatment .MF .
visual acuity - this definition the eye's ability to distinguish between two luminous points located at a minimum distance from each other, marked number.Those.visual acuity - the ability to see the structure of the object.Actually, this method of research to determine the level of the patient, but, unfortunately, this technique is not applicable for children under the age of 3-4 years of age.
Any reference to an ophthalmologist is an indication for the definition of visual acuity.Contraindications to this procedure do not.There are visual acuity for distance and near vision.
Checking distance vision
special tables are used to determine visual acuity.For a given - it Sivtseva table (with Russian letters) and Golovin (with Landolt rings), and for children - Orlova (with pictures).Opposite each row in these tables are written, visual acuity, which corresponds to this line.
This method is not a major, but it is indicative, ieit allows you to make the necessary plan for the further examination of the
For the procedure, you must have a table with the device Rota (wooden box with an electric lamp), Pointer, panel, set of trial spectacle lenses, chair.The patient sits on located 5 meters from the chair and table covers shield the left eye, and the research is conducted in visual acuity of the right eye;and then closes the right eye and conducted a study of visual acuity of the left eye.It should clearly stick to this order of eye research.
During the study, you need to keep your head straight, shield should be positioned vertically, you can not turn a blind eye covered, ieBoth eyes should be open, and you can not blink the eyes, pushing the flap to cover the eyes.Patients should call the doctor said the letter, the direction of the cuts rings or pictures.Each item should be shown for 2-3 seconds pointer, which point must be clearly visible.Make sure that the pointer away from the lens.The doctor begins the definition of visual acuity at random to display the symbols table number 10, and is gradually moving to the series with the largest objects.In patients with decreased visual acuity obviously starting to test with the top line, featuring a top-down one object in a row before the row where the patient makes a mistake, then it is necessary to return to the previous row.Visual acuity is measured at the line where the patient is correctly named objects.Allowed one mistake in 3-6 rows, and two errors in rows 7-10, but a doctor marks in the map.
examined beginning visual acuity without correction, and then adjusted, which allows more detail to evaluate visual function.If the patient uses spectacles, the eyesight and verified without them.
If the patient does not see the first line of the table, the doctor offers to count parted thumbs, and notes the distance from which the patient manages to do it.If the patient sees only the movement of the hand of a person and can not count fingers, then the doctor and writes this in his map.If the patient does not see the motion, it resorted to the definition of light perception.For this purpose, darkened room illuminated light beam striking the eye, and the patient should be noted if he sees light and, if he sees something which side.As a rule, the absence of light perception or incorrect projection of light associated with retinal or optic nerve lesions.If the patient's eye is not able to distinguish light from darkness, he is completely blind.
All results of the study physician enters the patient's card, where OD means right eye, OS - left eye, OU - both eyes.The results are recorded in fractions, which are written on top of the results of research of the right eye, and the bottom - left.
duration of the procedure, with good vision, when there is no need for the selection of the correction is 1-2 min., If the correction is required, the procedure may take about 20 minutes.
complications, this procedure does not.
Checking near vision
presence of high visual acuity does not mean that it will be high and close.For this purpose, a special table that includes multiple text letters with different magnitude.
The patient should keep the table at a distance of 33-34 cm from the eye.Visual acuity is checked individually for each eye, without correction (or points), and correction, and for the selection of glasses for near visual acuity determined for both eyes simultaneously.Visual acuity for near vision characterizes the smallest text that you can read the patient without errors.
Ophthalmologist Odnoochko EA