Interpretation of RNFLT values in multiple sclerosis-associated acute optic neuritis using high-resolution SD-OCT...

Area of Science:

• Neuroscience
• Ophthalmology
• Radiology

Background:

• Optical coherence tomography (OCT) is the gold standard for quantitative retinal nerve fibre layer (RNFL) thickness measurement.
• RNFL reduction may indicate lesion burden and diffuse axonal degeneration in multiple sclerosis (MS).
• Optic neuritis (ON) can cause RNFL changes that must be considered in MS patients.

Purpose of the Study:

• To investigate RNFL changes in patients with acute optic neuritis (ON) associated with MS.
• To assess the utility of OCT in detecting clinically silent RNFL loss in MS patients.
• To determine the role of RNFL thickness measurements in monitoring MS progression.

Main Methods:

• Studied 23 patients with acute ON (46 eyes) and 23 age/sex-matched healthy controls.
• Measured RNFL thickness using high-resolution spectral domain OCT (SD-OCT) with eye-tracking.
• Compared RNFL thickness in ON eyes, fellow eyes, and controls at baseline.

Main Results:

• OCT software identified RNFL atrophy in some acute ON and previous ON eyes.
• RNFL thickness was overestimated in a subset of ON and fellow eyes, falling within normal limits.
• Comparison with controls revealed RNFL atrophy suggestive of prior, clinically silent RNFL loss in 30.4% of eyes.

Conclusions:

• Single-time-point RNFL thickness measurements have limited value for detecting prior silent optic nerve injury.
• Comparing affected eyes to fellow eyes and controls is essential for detecting subtle RNFL changes.
• Further evaluation of OCT for MS disease monitoring is needed, as ON is often an initial MS symptom.