ABSTRACT
OBJECTIVE: To identify the ophthalmic causes of congenital nystagmus with normal eye examination by visual electrophysiologic tests. MATERIAL AND METHOD: Medical records of patients who presented with nystagmus and no other neurological sign before 6 months of age with normal eye examination, between February 2004 and February 2005, were reviewed Complete ophthalmic examination and visual electrophysiologic tests were performed to identify the ophthalmic causes of congenital nystagmus. RESULTS: Thirty-four patients had met the criteria. Leber's congenital amaurosis was diagnosed in 13 patients (38.2%) by non-recordable electroretinography (ERG) and normal visual evoked potential (VEP). Idiopathic infantile nystagmus was diagnosed in 12 patients (35.3%) by normal ERG and VEP. Achromatopsia was diagnosed in 8 patients (23.5%) by flat retinal cone ERG but normal rod ERG and VEP. Rod-cone dystrophy was diagnosed in one patient (3%) by abnormal rod and cone ERG CONCLUSION: Visual electrophysiologic study is helpful to identify the ophthalmic causes of congenital nystagmus. Leber's congenital amaurosis is a common cause in congenital nystagmus.