Blue-on-yellow mfVEP amplitude asymmetry may signal functional loss in preperimetric glaucoma patients

In this prospective case series, 14 of 30 patients (46.7 percent) with glaucomatous optic discs and normal standard visual fields demonstrated significant abnormality on amplitude asymmetry deviation plots of blue-on-yellow multifocal visual evoked potentials (mfVEP). The scotoma was monocular, corresponding to the eye with the worse disc in all 14 patients and also to the location of the worst affected rim in 13 of them. Average retinal nerve fiber layer (RNFL) thickness was significantly lower in patients with mfVEP defects than without (81.2 µm vs. 90 µm), while mean asymmetry of RNFL was significantly higher for patients with mfVEP defects than without (9.0 µm vs.3.0 µm).