Retinal nerve fiber layer evaluation by optical coherence tomography in Leber's hereditary optic neuropathy

Purpose: To study retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (StratusOCT) in patients with Leber's hereditary optic neuropathy (LHON). Design: Cross-sectional study. Participants and/or Controls: Thirty-eight patients with LHON were analyzed and compared with an age-matched control group of 75 patients. Patients with LHON were classified as having early LHON (E-LHON, n = 8) when the duration of the disease was shorter than 6 months and atrophic LHON (A-LHON, n = 30) when the duration was longer than 6 months. Methods: The fast RNFL thickness (3.4) scan acquisition protocol was used. Main Outcome Measure: Retinal nerve fiber layer thickness as measured by StratusOCT. Results: Compared with the control group, eyes with E-LHON showed a thicker RNFL in the 3600 average measurement (P<0.01) and in the superior (P<0.01), nasal (P<0.05), and inferior quadrants (P<0.05); no significant changes were detected in the temporal quadrant. Eyes with A-LHON revealed a thinner RNFL in all measurements (P<0.001); the fibers of the nasal quadrant showed the lowest amount of reduction (38% vs. 42%-49.8% in the other quadrants). In cases with A-LHON and visual recovery, RNFL was significantly thicker in all measurements (P<0.001), except the temporal quadrant, with respect to A-LHON without visual recovery. Conclusions: On the basis of OCT data, the RNFL is thickened in E-LHON and severely thinned in A-LHON. RNFL is likely to be partially preserved in A-LHON with visual recovery. The temporal fibers (papillomacular bundle) are the first and most severely affected; the nasal fibers seem to be partially spared in the late stage of the disease. (C) 2005 by the American Academy of Ophthalmology.