Pedometer
The eye scale, which defines the ability to distinguish shapes and details of objects from a certain distance, is a measure of the general vision. It can be done by an ophthalmologist, optometrist or nurse, but this examination is one factor of vision. On peripheral vision, depth of perception, and color discrimination.
Method of testing the sharpness
The Snellin Method
The Snellen method is based on a pattern of letters or symbols of different sizes, arranged in the form of columns and rows. This chart is used to determine the distance from which to see. To perform this test, the person who wishes to operate is required to stand six meters Plan, cover one eye with a telescope or use his hand, and then start reading from the top of the graph.
Method of random testing
The random test (Random E) is based on an outline consisting of a set of letters (E). This test is required to determine the direction of the character by pronunciation or reference. These tests are usually used in a more complex manner, especially when performed by an ophthalmologist; The way you look at a mirror-shaped graphic, using a variety of lenses, so that the person can see clearly, so this method helps determine the appropriate lenses to correct vision,
This test is often used in some special cases, for example, for people who do not know the alphabet, are embarrassed to read aloud, or who have a disability that prevents them from recognizing or reading letters.
Method of analyzing results
The analysis of the results reflects the severity of the consideration, such as 6/60, where the upper number is the distance from the chart. The lower number represents the distance from which the patient should be seen in case he has no weakness. If the person can not read the upper upper letter, A distance of one meter to the diagram, the vision is expressed in a 5/60 view, and if the character can not be seen within a meter, the finger counting method (CF) is used. The doctor raises his hands at different distances of less than one meter , And asks him to count his fingers, and if he can not count, the doctor resort to the way of hand movement, where he twists H in front of the patient, and his question is whether the movement is distinguished or not.