Identifying preperimetric functional loss in glaucoma: a blue-on-yellow multifocal visual evoked potentials study

Area of Science:

• Ophthalmology
• Neuroscience
• Visual Electrophysiology

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Early detection of glaucoma is crucial to prevent vision loss.
• Preperimetric glaucoma presents challenges for diagnosis using standard visual fields.

Purpose of the Study:

• To evaluate the efficacy of blue-on-yellow multifocal visual evoked potentials (BonY mfVEP) in identifying functional deficits in preperimetric glaucoma.
• To correlate BonY mfVEP findings with structural measures of glaucomatous damage.

Main Methods:

• A prospective case series involving 30 patients with glaucomatous discs but normal standard visual fields.
• Patients underwent BonY mfVEP, optic disc stereophotography, and optical coherence tomography (OCT) for retinal nerve fiber layer (RNFL) assessment.
• BonY mfVEP amplitude asymmetry and latency were analyzed and compared topographically with disc and RNFL findings.

Main Results:

• 46.7% of patients showed significant amplitude asymmetry abnormalities on BonY mfVEP.
• These defects corresponded to the eye with the worse optic disc appearance and RNFL thinning.
• Eyes with BonY mfVEP defects had significantly lower average RNFL thickness and higher RNFL asymmetry compared to those without defects.

Conclusions:

• BonY mfVEP, particularly amplitude asymmetry, shows promise as a tool for detecting functional loss in preperimetric glaucoma.
• This electrophysiological test may help identify patients at risk before significant visual field loss occurs.