Tests of Historical Interest in Functional Visual Loss

Abstract

Pioneers of ophthalmology developed ingenious methods to examine the attributes of the visual pathway. Many of today's testing methods for functional ophthalmic problems are derived from these historical testing methods. This chapter reviews historical tests for visual field defects, night vision, and a plethora of tests for complaints of blindness or diminished vision using sensory trickery with color, optical illusion, light polarization, prisms, and cylinders. Examiners also used image manipulation with haploscopes, including tubes that caused intersection of the lines of sight, pseudoscopes, amblyoscopes, and stereoscopes. There were also a variety of testing techniques that manipulated the lines of test optotypes and the distance to the test objects.