Abstract
Purpose: :
To describe a method for monitoring progression of glaucoma. The multifocal visual evoked potential (mfVEP) is used to detect visual field deficits in glaucoma. No study has used the mfVEP to assess progression.
Methods: :
Two groups with open–angle glaucoma (defined by gonioscopy, glaucomatous optic neuropathy and visual field defects) were tested. Group I, comprised 27 patients (44 eyes) who had repeat mfVEP testing within 50 days, and group II, 29 patients (44 eyes) with repeat tests 7–45 months apart. Monocular mfVEPs were obtained using a pattern reversal dartboard stimulus pattern. Monocular and interocular analyses were performed. [1] Data from the two visits were compared. The total number of abnormal test points with p < 5% within the visual field (total scores) and number of abnormal test points within a cluster (cluster size) were calculated. A cluster was defined as: 1) two contiguous points exceeding 1% or 2) three contiguous points exceeding 5% with one exceeding 1% and 3) contiguous points were within a hemifield. Data for group I provide a measure of test–retest variability independent of disease progression. Data for group II provide a measure of progression.
Results: :
For group I the correlations for the total scores for the interocular and monocular comparison for visit 1 vs. visit 2 were higher (r = 0.95, 0.87) than for group II (r = 0.83, 0.82). The correlations for cluster size were also higher for group I (r = 0.94, 0.87) than for group II (r = 0.87, 0.80). The difference in the total scores for group II between visit 1 and visit 2 for the interocular and monocular comparison was significant (p < 0.05) as was the difference in cluster size for the monocular (p < 0.05).
Conclusions: :
The change in the total scores and cluster size from visit 1 to visit 2 for eyes followed for > 6 months provides a possible method for assessing progression of glaucoma with the mfVEP technique. 1. Hood & Greenstein (2003) Prog Ret Eye Res.
Keywords: electrophysiology: clinical • visual fields