VEP test of the blue-sensitive pathway in glaucoma.

PURPOSE The blue-sensitive pathway in normal subjects and in patients with primary open-angle glaucoma (POAG) was tested with the pattern visual evoked potential (VEP) method under selective adaptation. METHODS Recording of pattern-onset VEP in response to blue (460-nm) stripes (0.88 c/deg) presented either without or with a bright yellow (570-nm) adaptation light (Maxwellian view, 33 degree diameter). Amplitude and peak times were evaluated, and the mean tritan score of the Farnsworth 100-hue test was determined. Age-matched normal subjects (n = 34) and (n = 32) patients with POAG were examined. RESULTS The amplitude and peak time of the VEP without selective adaptation did not discriminate normal subjects from the POAG group. With selective adaptation, the amplitude was reduced (P = 0.002) and its peak time delayed (P < 0.0001) in POAG, yielding a sensitivity of 75% and a specificity of 94%. The VEP measures only under selective adaptation correlated significantly in patients with POAG with the mean perimetric defect, with the optic disc damage, and with the 100-hue test. CONCLUSIONS Recording the blue-on-yellow VEP is a useful test in glaucoma research.