Visual Field Enlarged View

Retinal sensitivity is not an all-or-nothing affair. Sometimes a relatively weak flash at a particular spot that could not be seen becomes visible if the intensity of the light is increased. By flashing lights of varying intensity, the machine can ascertain the level of retinal sensitivity at each representative point in the visual field. The numbers on the print-out diagram indicate the level of intensity required to enable the patient to see the flash. The higher the number, the dimmer the light that could be seen.