A measurement of the field of vision.
A diagnostic test to determine the extent of the visual field. In the simplest form of perimetry, the doctor sits in front of the person being examined, who covers one eye. The doctor moves his or her hand from the side to the center of the field of vision and asks the person being examined to report when he or she can first see the movement. The same test is repeated for the other eye. More formal testing is usually done under the direction of a specialist. In the automated test, the person being examined sits in front of a concave dome and focuses on an object or light in its center. One eye is covered. A computer program flashes small lights at various positions within the dome, and the person being examined presses a button whenever he or she sees a flash. The test is repeated for the other eye. The perimetry device prints out a chart that maps the visual field and reveals blind spots or other abnormalities.
A test of the visual fields of the eye that assesses the extent of peripheral vision. The procedure does not normally form part of a routine test of vision but can be of value in assessing neurological diseases such as tumour of the brain.
Circumference; edge; border of a body.
A visual examination used to assess the scope of peripheral vision.