ABSTRACT
Visual field assessment may be undertaken by a variety of methods. Standard achromatic perimetry often detects visual field loss only when a substantial number of retinal ganglion cells are already lost. By using function-specific perimetry, it is proposed that earlier visual field loss detection can be achieved. Frequency Doubling Technology is based on an optical illusion that when a low spatial frequency sinusoidal grating undergoes high temporal counter phase flickering at 15 Hz or greater, gratings appear to double to twice their actual spatial frequency. Short-Wavelength Automated Perimetry visual field assessment is based on the principle that larger ganglion cells within the retina are selectively damaged during early glaucoma. The Humphrey and Octopus perimeters contain information of the decibel values expected at each point of the normal age matched visual field over a wide age range. Constriction of the visual field can be quantified in terms of extent of loss of visual field in degrees for a specific stimulus.
