Contribution of pattern electroretinogram and pattern visual evoked potential in early diagnosis of primary open angle glaucoma

Abstract

Pattern electroretinogram (PERG) combined with visual evoked potential (VEP) has become increasingly useful in clinical assessment of the anterior visual pathways. In regard to the PERG dependence on ganglion cell activity, we studied monocular PERG in 36 patients (71 eyes) with intraocular hypertension (6 eyes under topical beta-blockers) and in 10 patients (18 eyes) with advanced glaucoma, to estimate the potential effect of increased IOP on ganglion cells. We recorded simultaneous VEP to evaluate the retino-cortical conduction time. Referring to normal values obtained from 19 eyes (12 subjects), we found clear-cut PERG abnormalities in 20 eyes among ocular hypertensive patients with increased IOP. They were more altered in the advanced glaucomatous group. Two or three control exams were performed in 10 patients every 6 months: however such a short-time follow-up seems too limited to define the ERG prognosis value in this pathology. Comparing the PERG with the clinical routine assessments, we discuss its place in the diagnosis and in the follow-up of patients with ocular hypertension.