Multifocal visual evoked potential responses in glaucoma patients with unilateral hemifield defects

Area of Science:

• Ophthalmology
• Neuroscience
• Visual Science

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Early detection of glaucomatous damage is crucial for preserving vision.
• Unilateral hemifield defects in glaucoma present diagnostic challenges.

Purpose of the Study:

• To evaluate the efficacy of multifocal visual evoked potential (mfVEP) in detecting subclinical visual system damage.
• To assess mfVEP's ability to identify glaucomatous damage in unaffected visual hemifields of patients with unilateral defects.

Main Methods:

• An experimental study involving 16 patients with open-angle glaucoma and unilateral hemifield defects.
• Monocular mfVEPs and achromatic automated perimetry (AAP) were performed on both eyes.
• Interocular amplitude ratios were calculated and compared to 30 control subjects; cluster analysis determined mfVEP normality.

Main Results:

• mfVEP detected significant deficits in 93.8% of affected hemifields and 37.5% of apparently normal hemifields in glaucoma patients.
• Glaucoma patients showed a significantly higher percentage of abnormal mfVEPs in normal AAP hemifields compared to controls (37.5% vs 5.0%).
• mfVEP identified glaucomatous damage in unaffected hemifields where AAP showed normal results.

Conclusions:

• The mfVEP technique is sensitive in detecting glaucomatous damage in visual fields not affected by standard perimetry.
• mfVEP can reveal subclinical visual system damage in glaucoma patients with unilateral hemifield defects.
• This technique offers a valuable tool for early diagnosis and monitoring of glaucoma progression.