Structural and functional changes in glaucoma: comparing the two-flash multifocal electroretinogram to optical coherence tomography and visual fields

Abstract

Purpose: To correlate multifocal electroretinogram (mfERG) findings in the macular area of glaucoma patients with automated perimetry (visual fields) and with optical coherence tomography (OCT). Methods: A two-global flash mfERG (VERIS™) was recorded in 20 eyes with primary open-angle glaucoma. The root mean square was calculated, and three response epochs were analysed: the direct component (15–45 ms) and two induced components (IC-1 at 45–75 ms and IC-2 at 75–105 ms). The central 10° of the mfERG was compared to the central 10° of the OCT and of the visual field. Responses grouped in a superior and in an inferior semicircle, extending between 10° and 20°, were also compared to the corresponding areas of the OCT and of the visual fields. In addition, the area of the papillomacular bundle was also analysed separately. Results: In glaucoma patients, mfERG responses showed a significant positive association with retinal thickness in the central 10° for IC2 (p = 0.001) and a trend for IC1 (p = 0.066). A significant association was found between the central IC1 and IC2 of the mfERG and corresponding perimetric sensitivities expressed in linear units (p < 0.01). The OCT showed a positive association with visual field sensitivities (p < 0.05) in all areas examined (p < 0.05). Separation of the papillomacular bundle area did not improve structure–function association further. Conclusions: In our study, mfERG showed a statistically significant correlation with perimetric sensitivity measured in linear units and with structural macular changes detected with time-domain OCT.