Vision in multiple sclerosis: the story, structure-function correlations, and models for neuroprotection

Area of Science:

• Neuroscience
• Ophthalmology
• Clinical Neurology

Background:

• Visual dysfunction is a frequent symptom of multiple sclerosis (MS).
• Historically, MS clinical trials lacked sensitive visual outcome measures.
• Low-contrast letter acuity and optical coherence tomography (OCT) have emerged as key tools.

Purpose of the Study:

• To review the utility of visual function measures and OCT in assessing MS-related visual disability.
• To highlight optic neuritis (ON) as a model for testing neuroprotective and myelin repair therapies.
• To present data for developing clinical trial protocols in MS.

Main Methods:

• Correlating low-contrast acuity with MRI lesion burden, visual-evoked potentials, quality of life (QOL), and OCT-measured retinal nerve fiber layer (RNFL) thickness.
• Utilizing spectral-domain (SD) OCT for detailed retinal layer analysis, including ganglion cell layer.
• Analyzing longitudinal OCT data for axonal loss over time.

Main Results:

• RNFL thickness is significantly reduced in MS patients (92 μm) vs. controls (105 μm), and more so with a history of ON (85 μm).
• A 7-letter decrease in low-contrast acuity correlates with ~4.5 μm RNFL reduction.
• Longitudinal RNFL loss occurs even without acute ON, correlating with vision and QOL decline.

Conclusions:

• OCT enables non-invasive assessment of neuroprotection and repair in MS by quantifying RNFL and ganglion cell loss.
• ON serves as a valuable model for evaluating novel MS therapies.
• Standardized visual function and OCT data can inform future MS clinical trial design.