Summary
X-linked incomplete monochromatism is a hereditary bilateral retinopathy. It is non-progressive, and spares rods and blue cones. It is characterized by slight, regular pendular nystagmus that decrease with age, along with a loss of visual acuity and defective color sight. The fundus appears normal, apart from altered reflection of the fovea in some patients. Color vision is very much affected, with a combination of protanopia and deuteranopia. The photopic electroretinogram is altered. The gene causing this disorder has been identified, gene map locus Xq28. Treatment is symptomatic only. *Author: O. Roche, M.D. (July 2005)*.
