Photopic abnormalities in congenital stationary nightblindness.

Fourteen patients with congenital nightblindness, representing all three hereditary types, were studied, and all were found to have some type of photopic abnormality. The photopic abnormalities consisted of abnormal visual acuity, slower-than-nonnal final cone thresholds, elevated cone thresholds, subnormal photopic responses, slower-than-normal photopic aand b-wave implicit times, and low flicker fusion frequencies. One or more of these abnormalities were noted in all patients. Only visual acuity could be related to the specific type of inheritance involved. No other photopic or scotopic abnoimality bore a constant relation to the hereditary pattern. Congenital nightblindness, regardless of the hereditary type, is characterized by both scotopic and photopic abnormalities.