Retinal segmentation as noninvasive technique to demonstrate hyperplasia in ataxia of Charlevoix-Saguenay.

PURPOSE To present a new retinal layer segmentation technique for evaluation of nerve fiber hyperplasia in patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). METHODS Five patients with a molecular diagnosis of ARSACS and five age- and sex-matched healthy controls underwent a full ophthalmologic examination, which included a new technique to segment the retinal layers using Spectralis optical coherence tomography (OCT). Images and data were correlated with diffusion tensor color-encoded magnetic resonance imaging maps, diffusion tensor tractographies, and retinal anatomopathologic analysis. RESULTS Optical coherence tomography evaluation revealed increased thickness in the internal layers of the retina (inner limiting membrane, nerve fiber layer, and ganglion cell layer) in each patient with ARSACS compared with controls. These findings suggest that the presence of neurofilamentous hyperplasia in the retinas of patients with ARSACS correlates with the anatomopathologic findings. CONCLUSIONS We found evidence of ganglion cell and nerve fiber hyperplasia in the retinas of ARSACS patients. The etiopathogenic mechanisms of this disease thus require reconsideration.