Early retinal degeneration in Huntington's disease based on optical coherence tomography: A case-control study

Abstract Background: The purpose of this study was to analyze optical coherence tomography (OCT) parameters of the choroid and retina in subjects with pre-manifest and manifest Huntington's disease (HD). Methods: In this case-control study, the retinal parameters of patients with genetically confirmed HD and healthy controls were evaluated using spectral-domain optical coherence tomography (SD-OCT). Genetic and neurological assessments were performed besides a thorough ophthalmological examination. Contrast Sensitivity (CS) logarithm was evaluated using the Freiburg Vision Test. The association between OCT parameters and clinical and genetic characteristics was studied. Results: A total of ۹۱ subjects, including ۶۰ HD subjects (۶۰ eyes) and ۳۱ control subjects (۳۱ eyes) were eligible according to the inclusion and exclusion criteria. The range of the CAG (cytosine-adenine-guanine) repeat expansion size was ۳۸-۵۶ repeats, the mean ± standard deviation (SD) of the Unified HD Rating Scale (UHDRS) motor scores was ۳۶.۳ ±۲۹.۷, and disease duration was ۱۳.۷ ±۷.۲ years in HD subjects. Compared to the control group, significant decreases in the mean ganglion cell complex thickness and mean, temporal, superior, inferior, and nasal retinal nerve fiber layer (RNFL) thickness in HD subjects was revealed in OCT examination (P-values < ۰.۰۰۱, < ۰.۰۰۱, < ۰.۰۰۱, ۰.۰۲۳, ۰.۰۰۷ and ۰.۰۱۴, respectively). An inverse correlation between the disease duration and the mean RNFL thickness (r =- ۰.۴۷۰, P = ۰.۰۰۲) was found. Conclusions: Localization of retinal thickness loss shows a specific pattern of retinal neurodegeneration in HD, similar to Parkinson disease and mitochondrial diseases. The association with the disease duration confirms the progressive nature of these changes. Keywords: OCT spectral-domain optical coherence tomography SD-OCT Huntington's disease neurodegenerative diseases retina optometry ophthalmology macula retinal