Perimetry

perimetry

Perimetry is a test that maps a person’s visual field, showing what they can see out of the corner of each eye as well as straight ahead. During the test, you look at a central point while lights or targets appear in different places; your responses build a map of sensitive and less sensitive areas. This information helps detect and track conditions that affect peripheral vision, such as glaucoma, strokes, brain tumors, or retinal disease. Perimetry comes in several forms, from quick bedside checks to detailed automated tests in a clinic, and the choice depends on the clinical question. The results guide treatment decisions and help doctors understand how vision loss might affect daily activities like driving or walking. Because the test requires attention and clear instructions, results can vary with concentration, fatigue, or experience, so repeat testing and careful interpretation are often needed. Perimetry is valuable because it provides objective data about functional vision that cannot be seen in a simple eye chart exam. When used regularly, it helps detect subtle changes early and measure the effect of treatments over time.