# Evolution of Retinal Morphology Changes in Amyotrophic Lateral Sclerosis

## TL;DR

This study found no significant retinal layer thickness changes in early ALS patients compared to healthy controls using optical coherence tomography.

## Contribution

The study provides new evidence that OCT may not be effective for monitoring ALS progression in early stages.

## Key findings

- No baseline differences in retinal layer thickness were observed between ALS patients and controls.
- No significant thickness changes occurred in ALS patients over the observational period.
- A negative correlation was found between retinal layer thinning and higher modified Rankin scale scores.

## Abstract

Background/Objectives: To compare changes in the thickness of retinal layers between patients with amyotrophic lateral sclerosis (ALS) and healthy controls using optical coherence tomography. Amyotrophic lateral sclerosis is a degenerative disease of the upper and lower motoneurons with a rapidly progressive course, but non-motor symptoms such as decreased ocular motility and reduced visual acuity have also been reported. Specific biomarkers or surrogate parameters assessing neurodegeneration in ALS are of interest. Methods: In a retrospective, longitudinal study using optic coherence tomography of the retinal layers, we compared changes in the thickness of the layers between patients with ALS and healthy controls. Correlations to clinical scores, such as the modified ranking scale, were analyzed. Results: In our cohort of patients with early ALS (disease duration 5.15 ± 21.4 months at baseline), we neither observed differences in retinal layer thickness at baseline nor did the thickness changes in any retinal layer differ in comparison to healthy controls at baseline. Moreover, we observed no significant thickness changes over the course of the observational period in our patients with ALS. However, a correlation analysis revealed a negative association of the thickness change rates in the complex of ganglion cell and inner plexiform layer and the inner nuclear layer with a higher modified Rankin scale at follow-up. Conclusions: This study adds to the notion that OCT may not be a suitable tool to monitor atrophy and disease progression in ALS. However, further longitudinal studies with longer follow-up times and larger cohorts are warranted.