Prisms in strabismus management past, present, and future.

Given the optical properties of prisms, using them in strabismus treatment seems logical. However, theory and practice are two different things and the published literature in the field abounds in fruitless attempts at prismotherapy. This is because one is not only dealing with optical factors but also with sensory, motor, and accomodative factors. One must also remember that the act of binocular vision is a perceptual phenomenon.