Diagnosis and Management of Congenital Periodic Alternating Nystagmus

ABSTRACT

PURPOSE: To investigate clinical findings, diagnostic criteria and management for patients with congenital periodic alternating nystagmus (PAN). METHODS: A retrospective analysis of clinical findings and electrooculography (EOG) of patients with congenital PAN was performed. Thirteen patients diagnosed with congenital PAN from March 1992 to December 2002 were included. RESULTS: Of 13 patients, the median age at initial visit was 7 years old (range 1 to 30 years). Eight patients had abnormal head posture. The mean value for the period of alteration was 265.7 seconds. Six patients who received either the modified Kestenbaum-Anderson procedure or four rectus muscle recession showed a significant decrease in amplitude and/or frequency of nystagmus, and showed statistically significant improvement in visual acuity in LogMAR after the procedures by 0.33+/-0.09 in right eye, 0.34+/-0.11 in the left eye, compared with preoperative acuities of 0.43+/-0.19 and 0.38+/-0.09 respectively. CONCLUSIONS: Congenital PAN requires the evaluation of nystagmus along with a thorough evaluation of eye movement and EOG. Close follow is necessary to evaluate the pattern of nystagmus. Also, either modified Kestenbaum-Anderson procedure or four rectus muscle recession could be effective, depending on the presence of abnormal head posture.