To evaluate the role of objective perimetry using multifocal visual evoked potentials (mVEPs) in glaucoma practice, and to assess its utility in patients with inconclusive standard automated perimetry findings.
A retrospective case series of 436 consecutive subjects referred for glaucoma investigation who underwent testing with the AccuMap V1.3 mVEP system (ObjectiVision Pty, Ltd, Sydney, New South Wales, Australia) within a defined 12-month period. Sensitivity was determined by comparing this testing with that of standard automated perimetry and that used in a subgroup in whom masked stereoscopic optic disc photographs were used as an alternative reference standard. Overall clinical diagnostic outcomes were assessed.
The mVEP changes were correlated with the stage of disease and Humphrey mean deviation (r = 0.78). The overall sensitivity for detecting glaucoma with established subjective field loss was 97.5% (early glaucoma, 95.0%), whereas 92.2% of low-risk suspects had normal mVEPs. When masked disc assessment alone was used for diagnosis of abnormality, sensitivity of mVEP (80.6%) and Humphrey visual field results (81.9%) were similar, but mVEP specificity was better (89.2% vs 79.5%). The mVEP was particularly useful in assessing excessive subjective field loss (45 eyes) by showing a much closer correlation with the clinical picture.
Multifocal VEP is an effective method for detecting visual field loss in glaucoma. It provides a valuable aid to the clinician in categorizing patients with unreliable, variable, unconfirmed, or excessive subjective field loss.