Visual impairment and retinal and brain neurodegeneration: A population-based study

Area of Science:

• Neuroscience
• Ophthalmology
• Radiology

Background:

• Visual impairment and retinal neurodegeneration are linked to cognitive decline and brain atrophy.
• The mechanisms connecting these conditions, particularly transneuronal degeneration, require further investigation.

Purpose of the Study:

• To assess the relationship between visual function, retinal neurodegeneration, and brain/hippocampal atrophy.
• To investigate the role of the visual pathway in mediating these associations.

Main Methods:

• Analysis of baseline data from 3316 participants in the Rhineland Study.
• Utilized visual acuity (VA), optical coherence tomography (OCT), and 3T MRI (T1-weighted and diffusion-weighted) for retinal and brain imaging.
• Employed multivariable linear regression and structural equation modeling to analyze associations and mediation effects.

Main Results:

• Visual acuity and retinal ganglion cell layer thinning were associated with global brain and hippocampal atrophy.
• Retinal neurodegeneration partially mediated the effect of visual impairment on brain volume.
• Degeneration in visual tracts mediated the impact of retinal neurodegeneration on brain atrophy, accounting for 5.2%-23.9% of the effect.

Conclusions:

• Visual impairment and retinal neurodegeneration are robustly associated with brain and hippocampal atrophy.
• Findings support OCT-derived retinal measures as neurodegeneration biomarkers.
• Both general and transneuronal neurodegeneration along the visual pathway contribute to the link between retinal changes and brain atrophy.