What is a Refraction?

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What Is an Eye Refraction Test?

The refraction test, also called eye test or vision test, is a simple procedure performed by an eye doctor to check a person's eyesight. The refraction test determines the prescription of contact lenses or eyeglasses.

Procedure
o    The eye doctor asks the patient to read from a chart (around 20 feet away) while looking through a refractor (or phoroptor). The doctor changes the lenses in the refractor to choose the one that best suits the patient.
Considerations
o    People who have vision problems should take the test every two to three years to determine if they need a new prescription. People over the age of 40 should take the test more frequently.
Normal Result
o    The normal result of the refraction test is 20/20 vision, which means that the person has perfect vision.
Abnormal Results
o    An abnormal result may mean that the person has one of the following vision problems: nearsightedness, farsightedness, astigmatism, or presbyopia.
Other Conditions
o    The refraction test can also help the eye doctor determine if the person suffers from the following: ulcers or infections of cornea, detached retina, damaged retina, macular degeneration or blockage of blood flow to the retina.