perimetria

Perimetria, known in English as perimetry, is a set of tests used to map the visual field, the area of space a person can see at any given moment. The test measures light sensitivity across the retina, helping to diagnose and monitor diseases that affect the optic nerve or retina, such as glaucoma, optic neuropathies, and certain neurological or retinal disorders. Perimetria can be performed using various methods, including kinetic perimetry, where moving light stimuli of fixed size and intensity are moved across the visual field; and static perimetry, where fixed locations are tested with stimuli of increasing intensity to determine threshold. Modern equipment often provides automated static perimetry, with devices like the Humphrey Field Analyzer or similar, delivering rapid, standardized tests and graphical outputs.

During the examination, the patient fixes on a central point while stimuli are presented in different locations. The patient indicates when they see a stimulus, allowing the clinician to construct a map of sensitivity. Reliability indices, such as fixation losses and false positives/negatives, are used to assess test quality. The results may be presented as isopters in kinetic tests or as threshold maps in static tests, along with summary indices like mean deviation and pattern standard deviation, which summarize overall field loss and irregularity.

Interpreting perimetric results requires clinical context and consideration of patient factors, including age, cognitive status, and media clarity. Perimetria is a routine component of comprehensive ophthalmic evaluation and contributes to diagnosis, assessment of progression, and decision-making in treatment planning. See also visual field, glaucoma, and automated perimetry.