Visual Field Test

Mapping peripheral vision sensitivity

Overview

A visual field test, or perimetry, measures the extent and sensitivity of vision across the entire field, including peripheral vision, while the eye looks at a central fixation point. In standard automated perimetry, such as with the Humphrey Field Analyzer, spots of light of varying brightness are presented at fixed locations and the person presses a button when one is seen, producing a map of sensitivity. Kinetic perimetry, as with the Goldmann perimeter introduced in the 1940s, moves targets from non seeing to seeing areas to plot the boundaries of the field. Confrontation testing at the bedside offers a rough screen. Perimetry is essential in glaucoma, which produces characteristic defects such as nasal steps and arcuate scotomas, and in neuro ophthalmology, where defects that respect the vertical midline, such as hemianopias and quadrantanopias, help localize lesions of the optic chiasm and brain. Results include reliability indices, such as fixation losses and false positive responses, and serial tests are analyzed together to detect progression.