Perimetrische

Perimetrische, or perimetric, refers to perimetry—the set of tests and measurements used to map the visual field. Perimetry evaluates how well a person can detect light stimuli at different locations in the peripheral and central retina while maintaining steady fixation. The resulting data describe the extent and sensitivity of vision beyond the central point.

There are two main types of perimetry. Static automated perimetry presents stationary light stimuli at various intensities in predefined locations to determine light sensitivity at each point. Kinetic perimetry uses moving stimuli that expand from a non-seeing region to map the borders of the field, producing isopters that delineate measurable limits. Instruments commonly used for static testing include the Humphrey Field Analyzer and similar automated devices, while kinetic testing has historically relied on devices such as the Goldmann perimeter.

The output of perimetric testing includes both a spatial map of the visual field and numerical indices. Key clinical metrics often include mean deviation, which summarizes overall sensitivity loss; pattern standard deviation, which reflects irregularities in field sensitivity; and, in some systems, the visual field index. Reliability indicators, such as fixation losses and false-positive or false-negative responses, help assess test quality. Isopters generated in kinetic perimetry provide a contour view of the field, useful for detecting scotomas and determining field extent.

Perimetrische testing is used to diagnose and monitor conditions that affect the visual field, including glaucoma, optic neuropathies, retinal diseases, and certain neurological disorders. It requires patient cooperation and appropriate calibration, and results must be interpreted in the context of age, head position, and test-repetition effects.