Leber hereditary optic neuropathy ( LHON ): Retinal structure and function correlations

Abstract Purpose: LHON mainly affects small‐calibre ganglion cells in the papillomacular bundle which is electroretinographically reflected mainly as abnormal wave N95 of the pattern ERG (PERG) and photopic negative response (PhNR). In this study we investigated whether there is a reflection of the disease in oscillatory potentials (OPs), which are thought to reflect activity of the inner retinal generators, and whether there is a correlation with retinal structure as assessed by OCT segmentation to explore potential structural/functional biomarkers in LHON. Methods: Seven patients (mean age = 28.4 ± 5.6) with genetically confirmed LHON were compared to 12 healthy volunteers (mean age = 35.0 ± 12.1). PhNR, dark and light adapted OPs were derived from full‐field ERG signals. Segmentation analysis of retinal layers in ETDRS rings performed using the Heidelberg Engineering Spectralis SD‐OCT was correlated with oscillatory potentials derived from dark‐adapted and light‐adapted ERG signals filtered at 75 Hz cut‐off frequency that were shown to be affected in LHON in a previous study shown at this EVER meeting (Barboni et al.). Results: Dark‐adapted OP2 component filtered at 75 Hz cutoff frequency displayed a significant negative correlation with outer plexiform layer (OPL) thickness (Spearman correlation = 0.94; p = 0.005) for outer ETDRS ring. The OP3 and OP4 showed marginal correlation with the outer ETDRS ring (Spearman correlation = 0.812; p = 0.050 and Spearman correlation = 0.840; p = 0.036). Marginally significant positive correlation was found with the OP3 (Spearman correlation = 0.812; p = 0.050). We found no significant correlation between OPs and any other retinal layers, nor were light‐adapted PhNRs associated with OCT layer thickness. Conclusions: In chronic stage of the LHON, oscillatory potentials may be associated with OCT parameters, most notably dark adapted OP2 with OPL thickness. These data emphasize possible involvement of fast retinal generators as an additional biomarker in LHON patients.