Functional visual loss.

Neurologists frequently evaluate patients complaining of vision loss, especially when the patient has been examined by an ophthalmologist who has found no ocular disease. A significant proportion of patients presenting to the neurologist with visual complaints have nonorganic or functional visual loss. Although there are examination techniques that can aid in the detection and diagnosis of functional visual loss, the frequency with which functional visual loss occurs concomitantly with organic disease warrants substantial caution on the part of the clinician. Furthermore, purely functional visual loss is never a diagnosis of exclusion and must be supported by positive findings on examinations that demonstrate normal visual function. The relationship of true psychological disease and functional visual loss is unclear, and most patients respond well to simple reassurance.