Leber's Congenital Amaurosis (LCA) and hallucinations

   The eponym Leber's congenital amaurosis refers to the German ophthalmologist Theodor Karl Gustav von Leber (1840-1917), who was the first to describe the concomitant condition in 1869. LCA is considered a type of "amaurosis, due to an autosomal recessive disorder caused by one of a variety of genes involved in the development of the retina's photoreceptors. LCA typically begins with decreased visual acuity at the age of 1 year. The disease may manifest itself not only in the form of an annular scotoma with tunnel vision, due to damage to the retina's outer edge, but also in the form of a central scotoma which leaves peripheral vision intact. Other important symptoms include "night blindness and difficulty coping with glare. When LCA progresses to the level of " blindness, the condition may be complicated by " visual hallucinations (also referred to as ophthalmopathic hallucinations, as in " Charles Bonnet syndrome) or " synaesthesias. Clinically, LCA is associated with a variety of systemic and neurological disorders, including mental retardation, hydrocephalus, polycystic kidney disease, osteopetrosis, and skeletal abnormalities such as congenital hip dysplasia and a small mandible.

   References

   Armel, K.C., Ramachandran, V.S. (1999). Acquired synesthesia in retinitis pigmentosa. Neurocase, 5, 293-296.

   Leber, T. (1869). Über Retinitis pigmentosa und angeborene Amaurose. Archiv für Ophthal-mologie, 15, 1-25.

   Schroeder, R., Mets, M.B., Maumenee, I.H. (1987). Leber's congenital amaurosis. Retrospective review of 43 cases and a new fundus finding in two cases. Archives of Ophthalmology, 105, 356-359.