Comparitive Study of the use of multifocal electroretinogram versus visual field testing in evaluating cases of primary open angle glaucoma

Abstract

Primary open angle glaucoma is a common cause of blindness characterized by progressive loss of ganglion cell layer due to elevated intraocular pressure. This can impair the ocular perfusion pressure and disrupts the axoplasmic transport at the optic nerve head. Visual field testing has been used for diagnosis and follow up of glaucoma. Multifocal ERG is a new electrophysiological technique that has recently been used in assessment of glaucomatous damage. The aim of this study is to use the multifocal electroretinogram and the visual field to assess the visual function in POAG in its different stages, then correlating the results of both tests. The study was conducted on30 eyes of 15 adult patients who were presented to ophthalmology outpatient clinic of Ain shams university hospitals with POAG, and 15 control subjects matched for age and sex. The glaucoma patients were further grouped into 3 subgroups according to the mean deviation of the visual field into mild, moderate and severe subgroups.

All subjects underwent: medical history taking, measuring best corrected visual acuity, Intraocular pressure measurement, fundus examination. Humphery visual field (SITA standard 24-2) plotting, and multifocal ERG examination using RETI scan 21were used for this comparative study.

The visual field results showed statistically significant difference in the form of greater Mean deviation of the visual field in the glaucoma group when compared to the control group.

The results of the mfERG revealed prolonged latency of N and P waves of the multifocal ERG of patients, compared to the control group. No difference was found in the amplitude of waves between the two groups.