Occurrence of familial nonarteritic anterior ischemic optic neuropathy in a case series

Objective: To report on the occurrence of familial nonarteritic anterior is chemic optic neuropathy (NAION) in our NAION series. Methods: One hundred forty-eight consecutive retrievable cases of NAION wer e surveyed regarding the occurrence of NAION in other family members. Medic al records of affected family members were reviewed, and clinical character istics of documented familial NAION cases were described. Results: Of 79 patients who returned the survey, four reported one or more relatives with previously diagnosed NAION. There were nine cases of documen ted NAION in these four families. All cases occurred in siblings, with a me an age at onset of 55 years. Six patients had second eye involvement and in five, involvement became bilateral within 4 years after initial onset. Non e of the patients had diabetes; two had hypertension. Conclusion: A small number of patients with NAION may belong to a familial subclass. Three previous reports of familial NAION further support this hyp othesis.