Retinal layer thinning as a biomarker of long-term disability progression in multiple sclerosis.

Background: Peripapillary retinal nerve fibre layer and macular ganglion cell plus inner plexiform layer thinning are markers of neuroaxonal degeneration in multiple sclerosis.
Objective: We aimed to investigate the value of peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer thinning for prediction of long-term disability.
Methods: This is a 6-year prospective longitudinal study on 93 multiple sclerosis patients. Optical coherence tomography scans were performed at baseline, after 1, 2 and 6 years. Primary endpoint was disability progression after 6 years, defined as expanded disability status scale worsening and/or cognitive deterioration. Univariate and multivariate analysis was used to investigate the value of peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer to predict the primary endpoint.
Results: A total of 57 (61.3%) patients had disability worsening, 40 (43.0%) expanded disability status scale worsening and 34 (36.6%) cognitive deterioration. Mean peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer baseline thickness were 93.0 and 75.2 µm, and mean annualised peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer thinning rates over 6 years were 1.3 and 1.6 µm, respectively. Univariate and multivariate analysis revealed lower peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer baseline thickness and higher annualised thinning rates in patients with disability progression after 6 years. Effects were more pronounced for ganglion cell plus inner plexiform layer and expanded disability status scale worsening than for peripapillary retinal nerve fibre layer models and cognitive deterioration.
Conclusion: Ganglion cell plus inner plexiform layer and peripapillary retinal nerve fibre layer measurements depict neurodegeneration and predict disability progression in multiple sclerosis.