Developed by Eric S. Hussey, OD, FCOVD
Electronic rapid alternate occlusion (ERAO) using liquid crystal lenses is used to treat suppression of binocular vision (ICD 368.31), a defect affecting the sensory combination of two eyes’ images into actual binocularity; that is, simultaneous two-eyed, bi-foveal vision. Suppression remains a primary focus of the investigation of visual sensation in strabismus and amblyopia. However, abnormal binocular sensation in the form of suppression also occurs in the absence of strabismus and amblyopia as intermittent central suppression (ICS). As the name implies, intermittent central suppression is a repetitive on-and-off form of loss of central visual sensation. Active therapies for suppression, and ICS in particular, almost always involve two components: a bilateral (bi-optic) visual environment (e.g., a stereoscope) and visual motion.
ERAO treats suppression with on-off visual flicker which is a strong motion stimulus. Direct square-wave alternation between the eyes at a 5 Hz pace is fast enough that the central vision reads the signal as continuous; that is, as bilateral and with little central flicker. Paradoxically, then, electronic rapid alternate occlusion delivers a strong bilateral motion stimulus. These ERAO units are prototypes that have Doctor-changeable relative flash rates to prejudice the stimulus to either side to “drive” the central vision of a more strongly suppressed eye harder than the fellow eye, but while both eyes are still stimulated. Alternation rates can be set from 0 to 15 Hz, the higher rates possibly corresponding to the greater speed sensitivity in peripheral vision. Length of treatment times can be set in 5 min. increments with auto-shutoff. All settings are easily changed with an optical screwdriver.
Unit includes 1 pair goggles, control box, and instructional literature. Requires 2 AA batteries (not included).
NOTICE TO CONSUMER: Electronic Rapid Alternate Occlusion units are NOT sold to patients. Please have your doctor of optometry contact OEPF to obtain these units. These are not to be used without direct prescription by, and direct supervision and oversight by a doctor of optometry familiar with the science. The inventor, Dr. Hussey, is not only available to your doctor of optometry for consultation, but such consultation is encouraged.