Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein.

Vision Tests

Test Overview

Vision tests check many different functions of the eye. Some of the tests measure your ability to see details at near and far distances, check for gaps or defects in your field of vision, and evaluate your ability to see different colors. Others may check how sensitive you are to glare (brightness acuity), how well your eyes work together to provide depth perception, and more. Vision tests are usually done along with exams and tests that check the health of the eye. Here are some common tests that check for blurred or low vision.

Visual acuity (sharpness) tests.

These tests help your doctor find out if you have a problem that affects how well you can see. They measure the eye's ability to see details at near and far distances. The tests usually involve reading letters or looking at symbols of different sizes on an eye chart. Usually, each eye is tested by itself. And then both eyes may be tested together, with and without corrective lenses (if you wear them). Several types of visual acuity tests may be used.

Refraction test.

This test shows your level of refractive error, Opens dialog and finds out the right prescription for glasses or contact lenses. Refractive errors, such as nearsightedness, Opens dialog or farsightedness, Opens dialog, occur when light rays entering the eye can't focus exactly on the nerve layer (retina, Opens dialog) at the back of the eye. This causes blurred vision. Refraction is done as a routine part of an eye exam for people who already wear glasses or contact lenses. But it will also be done if the results of the other visual acuity tests show that your eyesight is below normal and can be corrected by glasses.

Visual field tests.

These tests are used to check for gaps in your side (peripheral) vision. Your complete visual field is the entire area seen when your gaze is fixed in one direction. The complete visual field is seen by both eyes at the same time. It includes the central visual field—which detects the highest degree of detail—and the peripheral visual fields.

Color vision tests.

These tests check your ability to distinguish colors. They are used to screen for color blindness, Opens dialog in people with suspected retinal or optic nerve, Opens dialog disease or who have a family history, Opens dialog of color blindness. Color vision tests are also used to screen applicants for jobs in fields where color perception is essential, such as law enforcement, the military, or electronics. Color vision tests only detect a problem. More testing is needed to identify what is causing the problem.

Current as of: July 31, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.