RETINAL NERVE FIBER LAYER FEATURES IN PATIENTS AFFECTED WITH LEBER’S HEREDITARY OPTIC NEUROPATHY

Abstract

Abstract: : Purpose: To investigate by Optical Coherence Tomography (OCT3) measurements the pattern of fiber loss in the peripapillary Retinal Nerve Fiber Layer (RNFL) of patients affected with Leber’s Hereditary Optic Neuropathy (LHON). Methods: 38 LHON patients (9 females, 29 men) carrying one of the three common pathogenic mtDNA mutations (nucleotides 11778, 3460 and 14484) were investigated in comparison with an age–matched control group of 70 individuals (30 males and 40 females). OCT3 was used to detect the peripapillary RNFL thickness (3.4mm diameter scan). One randomly selected eye was considered for each patient and control individual. Groups were compared by one–way analysis of variance. Results: Patients (n = 8) with early LHON (duration shorter than 6 months) revealed a trend towards a thicker RNFL in all quadrants but the temporal one, whose thickness was slightly reduced with respect to the control group. Patients (n = 30) with atrophic LHON (duration longer than 6 months) revealed a thinner RNFL in all quadrants (p < 0.001). Conclusions: Our study showed that the peripapillary RNFL tends to be thicker in the early stages of LHON when the acute phase of the disease is still active. This feature fits with the axonal swelling of the superior and inferior arcades on fundus examination (pseudoedema). The reduced thickness of the temporal quadrant at this stage indicates the earlier and preferential involvement of the small fibers of the papillo–macular bundle. In the atrophic phase of LHON, the progressive axonal loss leads to RNFL thinning in all quadrants.

Keywords: neuro–ophthalmology: optic nerve • nerve fiber layer • mitochondria