Retinal Ganglion Cell and Inner Plexiform Layer Loss Correlate with Visual Acuity Loss in LHON: A Longitudinal, Segmentation OCT Analysis

PURPOSE. Describe changes in the retina as vision loss progresses in Leber's Hereditary Optic Neuropathy (LHON) using spectral-domain optical coherence tomography (SD-OCT) autosegmentation, and determine if relationship exists between retinal changes and vision loss. METHODS. From patient records we identified nine LHON patients who underwent periodic neuro-ophthalmologic examinations and high-resolution SD-OCT as part of their care. We describe the impact of LHON progression on each retinal layer, and the relationship between these structural changes and visual acuity using generalized estimating equations and nonparametric tests. RESULTS. The thickness of the ganglion cell layer (GCL) and inner plexiform layer (IPL) decreased immediately or soon after symptom onset, and this decrease was associated with worsening vision: in the GCL a 1-mm(3) volume loss was associated with a 3.2 increase in logMAR visual acuity (95% confidence interval [CI]: 2.1-4.1); in the IPL a 1-mm(3) volume loss was associated with a 4.9 increase in visual acuity (95% CI: 6.5-3.2). The retinal nerve fiber layer (RNFL) also thinned, but not until after the GCL and IPL, and only in the papillomacular bundle (PMB) and temporal layers was thinning associated with vision loss. CONCLUSIONS. For the first time these analyses describe a structure-function relationship between the retinal changes that occur in LHON patients as their disease progresses and vision worsens. The structural changes in the GCL, IPL, and RNFL preceded structural changes in the other retinal layers. This analysis suggests that the first 6 months after diagnosis define a target for therapeutic intervention, and this can inform treatment guidelines for ongoing therapeutic trials.