Eyesight test measures patient’s correct vision which is required for handling the daily activities. Eye test also evaluates harm caused to the eyes as a result of the daily activities. The visual acuity of a person is measured with the documentation, if it is for the distant or near vision.
NeedThe eye test is performed in following cases.
- It may be necessary to undergo an eyesight test before obtaining a license.
- It is necessary to undergo the eyesight test for the people who regularly use display screen for the work.
- After 40 years age the capacity of the eye should be checked regularly.
- If you cannot see the things properly or have the symptoms like headache, eye inflammation or watering of the eye then you should go for the eye test.
No special preparation is required for this test. Patients are advised to bring the glasses if they use any. For such patients, tests are performed by wearing the glasses. Before some tests you have to put the drops in your eyes.
The eye testing will be carried out by a doctor or optometrist. The tests are carried out in a clinic of Optometrist or in a hospital.
The tests for visual acuity are often performed with the help of letter sizes viewed on the Snellen chart or the various symbol sizes as Tumbling E or Landolt Cs. In case, the visual acuity is below the largest optotype on the chart, the chart is moved closer to patient or the patient is moved closer to the chart till he reaches to a distance from were he can read it. Then the letter size and distance are noted. One eye is tested at a time and the ocluder is placed in front of the eye which is not being evaluated
If patient cannot read the chart from any distance, counting fingers test is performed where patient has to count the noted fingers from a specific distance.
In other type the hand is kept moving in front of the patient's face and he has to recognize if it is moving or not.
The eye's ability to perceive any light is distinguished in light perception. If the patient cannot see the light in any case then it is concluded that he is total blind.Sometimes, there are the chances of being the binocular visual acuity better than the monocular.
Acuity is the reciprocal value of size of gap (measured in arc minutes) of the smallest Landolt C that can be reliably identified. 20/20 is same to the value 1.0. At some places, the acuity expressions are used as decimal number and vulgar fraction. If the unit of measurement is foot, then it is expressed as 20/20 and in meters as 6/6. You have to wear the glasses or contact lens. The surgeries like lacer therapy or other surgeries like cataract, glaucoma are advised as per the result of the test.
Most of the tests are painless. In case of a diabetic retinopathy that cause vision loss, if it is recognized in early stages then the complications can be reduced. The doctor patient communication should be good for discussing various factors. The measurement of the real visual acuity is depending on the factors consulted with patient. So patient’s illiteracy, intoxication, motor inability, unwillingness are the causes behind incorrect test results.
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