Background Optical coherence tomography (OCT) is a novel, non-ionising, retinal nerve fibre layer (RNFL) imaging modality with rapid, consistent data acquisition and a much shorter scan time versus MRI. In Alzheimer’s disease, Parkinson’s disease and multiple sclerosis, RNFL loss is proposed as a surrogate marker of brain neuronal loss. In related polyglutamine disorders, Spinocerebellar Ataxia 7 (SCA 7), retinal degeneration is well established clinically. In a recent OCT study of 9 Spinocerebellar Ataxia 1 (SCA1) patients, significant RNFL loss versus controls was seen. In Huntington’s disease, drosophila models show photoreceptor degeneration, while both R6/1 and R6/2 mouse models demonstrate loss of rod and cone function, photoreceptor degeneration, deficit in cone response to electroretinogram and loss of cone opsin and transducin protein expression.
Aim To determine if optical coherence tomography is a viable biomarker in Huntington’s disease.
Methods Neuro-opthalamological assessment and optical coherence tomography (OCT) was carried out in 51 subjects, comprising healthy controls, premanifest, early, moderate and juvenile stage participants.
Results There is evidence of statistically significant (p < 0.01) reduced pooled (left and right) macular volume in HD subjects (8.71+/- 0.22 mm3) versus age and sex-matched controls (8.47 +/- 0.31 mm3). However, no significant retinal nerve fibre layer thinning is noted in HD participants. There is no indication of a difference in ophthalmological disease between groups.
Conclusions Macular volume is reduced in HD subjects versus healthy controls on OCT imaging, suggesting some potential as a biomarker. Furthermore OCT was reasonably tolerated by the majority of subjects. Retinal nerve fibre layer loss between controls and HD participants was not significantly different. Further work is required to determine if macular volume changes correlate with disease stage and brain atrophy.
- Optical Coherence Tomography
- Macular volume loss