[Neurodegeneration and retinal changes-A literature overview]

The eyes and the central nervous system (CNS) develop from the same embryonic tissue which explains why retinal changes have been observed in various neurological and neurodegenerative diseases. These changes can be visualized in vivo on a cellular and subcellular level using optical coherence tomography (OCT). This article summarizes which retinal changes occur and how these could be used as potential biomarkers of neurodegenerative diseases.

The article gives an overview of the literature on the relationship between neurodegeneration, OCT-based retinal characteristics and cognitive functions.

A literature search was carried out in PubMed until February 2025. The search terms "neurodegeneration", "dementia", "mild cognitive impairment", "mild neurocognitive disorder", "OCT", "OCT angiography (OCT-A)", "retinal biomarkers", "retinal layer", "RNFLT", and "GCL" were used. Relevant publications were reviewed, analyzed and summarized.

In OCT‑A Alzheimer's disease, frontotemporal dementia, vascular dementia, amyotrophic lateral sclerosis, multiple sclerosis (MS) and Parkinson's disease demonstrate an association with a reduced retinal nerve fiber layer (RNFL) and the ganglion cell layer (GCL) thickness as well as an enlarged foveal avascular zone.

So far retinal changes could not be specifically assigned to a particular form of neurodegenerative disease,; however, they could be meaningful in neuropsychological/radiological examinations and for longitudinal monitoring, as already recommended for MS. Further longitudinal studies are needed to identify and validate retinal biomarkers (patterns).