glossary

Ability to discern the details of an object. A normal average eye an angle of one minute of arc (1/60th degree). Assessment of the eye’s ability to distinguish object details and shape, using the smallest identifiable object that can be seen at a specified distance (usually 20 ft. or 16 in.) and letter height (8.87mm).

Field of vision: The entire area that can be seen when the eye is directed forward, including that which is seen with peripheral vision. The area visible to an eye that is fixating straight ahead.

A visual field test is an examination that may be performed to analyze a patient’s visual field. The test may be performed by a technician directly, with the assistance of a machine, or completely by an automated machine. Machine based tests aid diagnostics by allowing a detailed printout of the patient’s visual field. See Perimetry