The Humphrey visual field is a diagnostic test to measure visual fields, or perimetry. The Humphrey visual field test measures the entire area of peripheral vision that can be seen while the eye is focused on a central point. During this test, lights of varying intensities appear in different parts of the visual field while the patient's eye is focused on a certain spot. The perception of these lights is charted and then compared to results of a healthy eye at the same age of the patient to determine if any damage has occurred.
This procedure is performed in about 20 minutes and is effective in diagnosing and monitoring glaucoma. Patients with glaucoma will undergo this test on a regular basis to determine the progress of the disease. The Humphrey visual field test can also be used to detect conditions within the optic nerve of the eye, and certain neurological conditions as well.