Abstract
Purpose. To determine the relationship among photopic negative response (PhNR) of the electroretinogram (ERG), retinal nerve fiber layer (RNFL) thickness, and the visual field in normal and glaucomatous patients. Methods. Thirty-eight normal volunteers and one hundred twenty-four patients with Primary open-angle glaucoma (POAG) were enrolled in the study. The PhNRs were elicited by white stimuli on a white background and red stimuli on a blue background. The visual field parameters were measured using the standard automated perimetry (SAP). The spectral domain optical coherence tomography (SD-OCT) was used to measure the retinal nerve fiber layer (RNFL) thickness around the optic disc. Results. The PhNR amplitude (W/W, B/R), MD, and mean RNFL thickness in POAG eyes were significantly lower than normal eyes (P = 0.001). The R value in Normal + Glaucomatous group was higher than that of the only glaucomatous group. The R values of PhNR amplitude (B/R) with MD and RNFL were higher than those of PhNR amplitude (W/W). Significant linear association was found in the relationship between RNFL thickness and PhNR amplitude (B/R) (R 2 = 0.5, P = 0.001). However, significant curve associations were found in the relationship between MD and PhNR amplitude (B/R) and RNFL thickness (R 2 = 0.525, 0.442, P = 0.001). Conclusions. The ganglion cell activity can be more efficiently evaluated with the PhNR elicited with a red than with a broadband stimulus. The linear relationship between the PhNR amplitude and RNFL thickness indicates that inner retinal function declines proportionately with neural loss in glaucomatous eyes. The PhNR and RNFLT are more objective tools to detect glaucomatous damage than visual field.
Highlights
Glaucoma is an optic neuropathy characterized by progressive loss of retinal ganglion cells (RGCs) and their axons, changes in optic disc topography, and associated deficits of visual function
The purpose of this study was to evaluate the clinical significance of the photopic negative response (PhNR) recorded from eyes with Primary open-angle glaucoma (POAG) by correlating the amplitudes of the PhNR with the retinal nerve fiber layer thickness (RNFLT), and mean deviation (MD) is obtained in glaucomatous eyes by the newer instruments
The reduction of the PhNR amplitude correlated with the degree of visual field defect and with the neural loss assessed by anatomic structure of retinal nerve fiber layer (RNFL) [14,15,16]
Summary
Glaucoma is an optic neuropathy characterized by progressive loss of retinal ganglion cells (RGCs) and their axons, changes in optic disc topography, and associated deficits of visual function. Detection is important to initiate treatment in the earliest phases of glaucoma and to avoid its natural progression to blindness. It was generally believed that the neural activity of retinal ganglion cells (RGCs) contributes little to shaping the ERGs. a response driven by RGCs receiving signals from cones was newly discovered and called the PhNR [1]. The PhNR is strongly attenuated in primates with experimentally induced glaucoma [1] and after an intravitreous injection of tetrodotoxin that blocks the voltage-gated sodium channels in retinal neurons including RGCs, amacrine cells, cone bipolar cells, and cones [2,3,4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
