Optical coherence tomography in the diagnostics of neurodegenerative diseases

Purpose
Review of the literature on the use of optical coherence tomography (OCT) in the diagnosis of the chosen neurodegenerative diseases – Alzheimer’s disease (AD) and Parkinson’s disease (PD). The review also includes multiple sclerosis (MS), where the neurodegenerative process is secondary to inflammatory-autoimmune processes.

Views
The retina is an integral part of the central nervous system (CNS), so neurodegenerative processes also affect it. The transparency of the eyeball causes the retina to be a “window into the brain” and by using OCT we can look at the CNS. Thanks to the specific structure of the retina – its lack of myelin and small number of glial cells – the progress of neurodegenerative diseases can be assessed at a very early stage and, thanks to OCT, quantified. The parameters associated in the literature with OCT – RNFL (retinal nerve fiber layer) and GCL (ganglion cell layer) – were analysed in correlation to other diagnostic examinations and functional tests in chosen diseases (AD, PD, MS). Multiple studies have also evaluated the efficacy of OCT in patients with stroke, spinal-cerebellar ataxia, obstructive sleep apnea, congenital diseases of CNS, and with prion diseases.

Conclusions
OCT is a precise additional examination that allows to assess the process of neurodegeneration at a very early stage. The results should be interpreted with reference to clinical symptoms and other diagnostic techniques.