Optic nerve head dimension as biomarker in Leber hereditary optic neuropathy

Abstract

Aims/Purpose: To study the optic nerve head (ONH) dimension in symptomatic and asymptomatic patients with Leber hereditary optic neuropathy (LHON) and to correlate ONH parameters with genotype and clinical phenotype.Methods: Seventy‐eight affected patients, 175 asymptomatic carriers, and 29 age‐matched healthy controls were enrolled in the study. All patients underwent ONH optical coherence tomography (OCT) measurements by DRI OCT Triton (Topcon, Japan) and were analysed with the Orion custom software (Volexeron, CA, USA). The following parameters were obtained for each eye: disc area, horizontal and vertical diameter; retinal nerve fibre layer (RNFL) and ONH volume. For the comparison of the different parameters the ANOVA with Bonferroni post‐hoc test was performed.Results: LHON‐affected patients appeared to have smaller ONH size parameters compared to control cases, but only the vertical disc diameter of patients with mutations 11 778 and 14 484 were statistically significant. Also, carrier patients with the mutation 11 778 presented a statistical significantly smaller vertical disc diameter compared to controls, instead 14 484 carriers presented a bigger diameter. ONH volume of all affected patients was significantly smaller. Moreover, asymptomatic 11 778 carriers older than 35 years were significantly smaller. Linear regression sustained the relationship between age, volume, and RNFL, unlike between age and disc area.Conclusions: This study exposed the differences of ONH size in LHON‐affected and ‐carrier patients with different mutations: smaller disc in 11 778 affected and unaffected patients and larger disc in 14 484 carriers. A strong correlation was found between ONH volume both in affected patients and carriers older than 35 years old. These results highlight the importance of the 3D ONH structure as a potential biomarker to support clinicians in the characterization of symptomatic LHON patients and possibly at‐risk mutation carriers with different genetic mutations and clinical course.