Polaroid scotometer: a new device to chart suppression scotomata.

Abstract

Suppression, an active inhibition of vision in one eye under binocular conditions, is a sensory adaptation in concomitant strabismus. The characteristics and extent of suppression differ not only in different types of strabismus but also in the same type under different testing conditions, which may differ in their degree of dissociation. The findings in exodeviations have thus varied from regional suppression to hemiretinal trigger, and in esodeviations from two point scotoma to single large scotoma. There is a need for a simple but less dissociative test to chart the fields under binocular conditions. We have devised a new, simple instrument based on polaroid dissociation. The findings corroborate the findings of more sophisticated tests like phase-difference haploscope.