The Pulfrich phenomenon; clumsiness and collisions which can be ameliorated.

The Pulfrich phenomenon has been described many times but usually just as an interesting academic issue with only diagnostic significance. The phenomenon is due to the fact that patients with unilateral optic neuropathy due to ischaemia, facial injury or multiple sclerosis may have delayed transmission of retinal responses to light from one eye to the brain. This leads to an altered and incorrect interpretation of the pathway and direction of moving targets. Clinicians should be aware of the unique symptomatology of the Pulfrich phenomenon because it is often difficult for patients to describe their symptoms which can be both unpleasant and troublesome. An appropriate tint in either a spectacle or contact lens over the normal eye delays retinal conduction, so re-establishing visual processing symmetry and ameliorating the symptoms.