Retinal nerve fiber layer thickness variability in Leber hereditary optic neuropathy carriers

PURPOSE. Recent investigations suggested that unaffected carriers of Leber hereditary optic neuropathy (LHON) may show subclinical visual alterations. Structural changes have also been detected by optical coherence tomography (007), which revealed a temporal thickening of the retinal nerve fiber layer (RNFL). These changes may reflect compensatory effects such as mitochondria accumulation within the RNFL axons. This study aimed to investigate whether the RNFL of LHON carriers shows greater than expected thickness variations, which may reflect transient subclinical changes, over the course of years.METHODS. Using Stratus OCT, the RNFL thickness was measured yearly from 2005 to 2008 in 24 Brazilian LHON carriers, all with homoplasmic 11778/ND4 mtDNA mutation. An Italian sample of 20 healthy subjects served as a control. Data were compared also to a previously published sample (n=59) of glaucomatous eyes.RESULTS. the LHON carriers showed test-retest standard deviations that were larger than normal controls in the temporal (p=0.004), superior (p