This eye test measures your ability to see objects at specific distances.
You sit in a chair that has a special device (called a phoropter or refractor) attached to it. You look through the device and focus on an eye chart 20 feet (6 meters) away. The device contains lenses of different strengths that can be moved into your view. The test is performed one eye at a time.
The eye doctor performing the test will ask if the chart appears more or less clear when different lenses are in place.
If you wear contact lenses, ask the doctor if you need to remove them and for how long before the test.
This test can be done as part of a routine eye exam. The purpose is to determine whether you have a refractive error (a need for glasses or contact lenses).
For people over age 40 who have normal distance vision but difficulty with near vision, a refraction test can determine the right power of reading glasses.