Abstract
Recently the view that congenital tritanopia does not exist and that tritanopia is always secondary to ocular disease has been revived. It has been suggested that previous accounts of congenital tritanopia have not adequately excluded ocular disease and specifically that tritanopia thmight to be congenital may in fact be secondary to dominantly inherited juvenile optic atrophy, a disease which often presents with signs sufficiently subtle as to go unnoticed by the patient and the examiner. This paper reports the investigation of six tritans from two families already documented in the literature as exhibiting congenital tritanopia. The investigation sought evidence of ocular disease and in particular evidence of dominantly inherited juvenile optic atrophy. No such evidence was found and it is concluded that their tritanopia is not acquired. It seems that congenital tritanopia does exist and moreover shows distinct differences from tritanopia acquired secondary to dominantly inherited juvenile optic atrophy.