title: Differential diagnosis of typical and atypical congenital achromatopsia. Analysis of a progressive foveal dystrophy and a nonprogressive oligo-cone trichromasy (general cone dysfunction without achromatopsia), both of which at first had been diagnosed as achromatopsia.
abstract: Report on two patients whose symptoms suggested the presence of congenital achromatopsia. In one case there was indeed total colour blindness, but a normal photopic ERG. Here, achromatopsia is the present stage in a process of slow functional decay of the central retina. Most probably the underlying disorder is progressive foveal dystrophy, a central form of cone dystrophy. In the other case there was a nonrecordable photopic ERG, but trichromatic colour vision. This appears to be another patient with oligo-cone trichromasy (general cone dysfunction without achromatopsia), as described by Van Lith.
mesh_terms: D000328:Adult; D003118:Color Perception; D003117:Color Vision Defects / Q000151:congenital / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D004596:Electroretinography; D006801:Humans; D008268:Macular Degeneration / Q000150:complications; D014787:Vision Tests; D014792:Visual Acuity