Nevertheless, good eyes need representatives of many professions. And it`s your own, not improved by glasses or contact lenses. Physiologically, the person`s vision is structured like this: light reflected from objects passing through the retina of the eye is refracted onto the lens of the eye, and it in turn transmits the image to the brain, where an understandable picture of the world is formed.
Normal vision is the sharpness equal to one. However, this value for a person is not the limit. There are people with visual acuity of +1.5 and -1.5. If they have reduced visual acuity, then you should consult an ophthalmologist.
The vision test, as a rule, should be done once a year. For this, a person comes to the office of an ophthalmologist. They check vision with the help of Sivtsev`s table (Snellen). It looks like this. On a sheet of paper, letters of different sizes are printed (image transmission by projection is possible). The uppermost letters are the largest. The smallest letters are located at the bottom of the table. To conduct the vision test, the table is located from the test person at a distance of at least 4 meters. A person sits on a chair, closes his right eye and reads the smallest line of those that he can discern. Then a similar procedure is performed with the left eye. If a person can read the lowest line, then his vision is equal to one. If glasses are prescribed, visual acuity is checked in glasses. Testing is carried out under strictly defined table illumination.
You can also find out if your vision is poor or at home. To do this, you buy or print from the Internet a table for checking your eyesight. It is fixed to the wall, preferably without windows. To conduct the test will help a person with excellent vision, who sees the lowest line. The subject reads the smallest lines that he can discern, and the examiner marks errors. Of course, at home to determine -2 vision or +1.5 impossible, but you can find out if it has deteriorated or deteriorated.
In the event that a drop in visual acuity is detected, you should consult an ophthalmologist. The medical worker prescribes treatment, writes glasses or contact lenses.