Background Previous reports of ocular abnormalities in Huntington’s disease (HD) have detailed eye movement disorders but not whether the nerve fibre layer at the back of the eye is affected. This layer has been shown to be thinned in neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease.
Aims The objective of this case-control study was to investigate optic nerve and macular morphology in HD using optical coherence tomography (OCT).
Methods A total of 26 HD patients and 29 controls underwent a thorough ophthalmic examination including spectral domain OCT scans of the macula and peripapillary retinal nerve fibre layer (RNFL). Genetic testing results, disease duration, HD disease burden scores and Unified HD Rating Scale motor scores were acquired for HD patients.
Results Temporal RNFL thickness was significantly reduced in the HD group (62.3 vs. 69.8 μm, p = 0.005), and there was a significant negative correlation between temporal RNFL thickness and disease duration (R (2) = −0.51, p = 0.04). Average peripapillary RNFL thickness was not significantly different between the HD and control groups. There was a significant negative correlation between macular volume and disease duration (R (2) = −0.71, p = 0.002), and motor scores (R (2) = −0.56, p = 0.01). Colour vision was significantly poorer in the HD group.
Conclusions Temporal RNFL is preferentially thinned in HD patients, possibly implicating mitochondrial dysfunction as the temporal RNFL is reduced in the patients with some mitochondrial disorders, including Leber’s hereditary optic neuropathy. The correlation between the decrease in macular volume and temporal RNFL, and increasing disease severity suggests that OCT may be a useful biomarker for disease progression in HD. Larger, longitudinal studies are required.
- Optical coherence tomography
- Retinal nerve fibre layer