Visual evoked responses in the assessment of field defects in glaucoma
J. M. Cappin and S. Nissim
A technique for producing steady state visual evoked responses (VERs) to
pattern reversal stimulation of retinal areas corresponding to discrete
field quadrants is described. Patients examined included 10 normal
individuals, 11 patients with ocular hypertension, and 21 with glaucomatous
field defects (unilateral except in two cases with bilateral defects). The
VERs relating to normal homonymous field quadrants were in phase in all
three groups, excluding patients with cataracts. The VERs corresponding to
quadrants with small field defects showed a phase shift compared with
responses from normal homonymous quadrants in all cases, but were not
detectable if the defect filled more than three quarters of the quadrant
tested in most cases. The method offers a means for the objective
assessment of visual fields in patients with unilateral optic nerve
lesions, provided that central visual acuity is 20/80 or better
