Multifocal VEP assessment of optic neuritis evolution.

Area of Science:

• Ophthalmology
• Neuroscience
• Visual Electrophysiology

Background:

• Optic neuritis (ON) is an inflammatory condition affecting the optic nerve.
• Assessing visual pathway integrity post-ON is crucial for prognosis, particularly for predicting conversion to multiple sclerosis (MS).
• Multifocal visual evoked potentials (mfVEP) measure the electrical activity of the visual pathway.

Purpose of the Study:

• To evaluate changes in multifocal visual evoked potentials (mfVEP) in affected and fellow eyes of patients with optic neuritis (ON) during the first year post-attack.
• To correlate mfVEP parameters with retinal nerve fiber layer (RNFL) thickness.
• To compare mfVEP changes in patients with different risks of developing multiple sclerosis (MS).

Main Methods:

• mfVEP recordings and RNFL thickness measurements were analyzed in 87 ON patients and 25 controls.
• Patients were categorized into multiple sclerosis (MS), high risk (HR), and low risk (LR) groups for MS conversion.
• Longitudinal analysis was performed over the first year following the ON episode.

Main Results:

• Visual evoked potential amplitude recovery and latency shortening were fastest within the first 3 months post-ON.
• The MS group exhibited the most significant amplitude reduction and latency delay in the ON eye, with concurrent deterioration in fellow eyes.
• Retinal nerve fiber layer thickness strongly correlated with mfVEP amplitude by 3 months post-ON.

Conclusions:

• mfVEP amplitude serves as an early predictor of axonal loss following optic neuritis.
• The more severe visual pathway involvement in MS patients may be linked to subclinical inflammation.
• The study suggests that mfVEP can detect visual pathway changes even in fellow eyes, potentially indicating subclinical involvement.