Photopic negative response of full-field electroretinography in patients with different stages of glaucomatous optic neuropathy

Abstract

PurposeTo evaluate photopic negative response (PhNR) discrimination ability between healthy and glaucomatous patients. MethodsNinety eyes of 50 patients with primary open angle glaucoma (POAG) and 45 eyes of 23 healthy age- and sex-matched controls were investigated. Based on European Glaucoma Society criteria, POAG patients were divided into three groups: early, moderate and advanced glaucoma. Following measurements were analysed: mean defect (MD) from Humphrey Visual Field Analyzer, SITA standard 24-2 white on white perimetry; nerve fibre index (NFI) obtained from scanning laser polarimetry; and GDx and PhNR amplitude and PhNR/b-wave ratio. PhNR was elicited by red stimuli with flash strength of 1.6 cd s/m2 on blue background of 25 cd/m2. Correlations between retinal ganglion cells function (PhNR), retinal sensitivity (MD) and structure (NFI) were calculated. Sensitivity and specificity of PhNR parameters were calculated with standard formulas. Receiver operating characteristic (ROC) curves were used to determine optimal cut-off values. The area under the curve (AUC) was used to compare the ROC curves results between PhNR amplitude and ratio.ResultsPhNR amplitude and ratio were significantly reduced in early, moderate and advanced glaucoma groups compared to controls. The sensitivity and specificity to detect glaucoma in early POAG were equal to 53.3 and 90.0 % for PhNR amplitude and 60.0 and 70.0 % for PhNR ratio; in moderate POAG 63.3 and 80.0 % for PhNR amplitude and 60.0 and 86.7 % for PhNR ratio; and in advanced POAG 76.6 and 80.0 % for PhNR amplitude, 90.0 and 73.3 % for PhNR ratio. There were no significant differences between AUC for PhNR amplitude (0.76–0.86) and PhNR ratio (0.78–0.86), p > 0.05. PhNR amplitudes and ratios correlated significantly with MD measured by SAP and NFI obtained from GDx (p < 0.05). PhNR amplitude significantly decreases with advancement of visual field defects in glaucoma patients.ConclusionsPhNR reveals dysfunction of RGCs in early, moderate and advanced stage of POAG. PhNR has good discrimination ability in detecting glaucomatous patients. PhNR might be a useful test in glaucoma diagnosis.

Asiatic Acid Prevents Retinal Ganglion Cell Apoptosis in a Rat Model of Glaucoma

“…Retinal ganglion cell dysfunction precedes RGC death, and RGC dysfunction may be reversible at the early stage of RGC injury ( Porciatti, 2015 ). We analyzed the PhNR, a sensitive marker of inner retinal layer function in patients with glaucoma ( Preiser et al, 2013 ; ElGohary and Elshazly, 2015 ; Kirkiewicz et al, 2016 ), to determine whether AA improved retinal function in a rat model of experimental glaucoma ( Figures 6A – D ). PhNR amplitudes were significantly reduced by 63.22 ± 13.89% (mean ± SD) and 57.88 ± 6.95% in the COHT eyes and COHT+vehicle eyes compared to NC eyes at 2 weeks ( Figure 6E ).…”

Comparing three different modes of electroretinography in experimental glaucoma: diagnostic performance and correlation to structure

“…The utility of the PhNR for assessment of retinal ganglion cell function in glaucoma was first described by Viswanathan and colleagues [36,42] and has since been confirmed by numerous other investigators in clinical studies, particularly when normalized to B-wave amplitude [59,39,60,22,24,61–64] as well as in laboratory studies of both rodent [65,66] and NHP optic nerve injury models [28]. It is possible that limiting the stimulus to localized areas of the macula [67–69,62,23] and/or to a narrower spectral range (with a goal of stronger chromatic contrast) [43] might offer greater improvement of diagnostic performance of the PhNR as compared to the conditions used in this study.…”

The Genetics of Leber’s Hereditary Optic Neuropathy: A Literature Review

“…Numerous studies have evaluated the predictability of disease pathology such as glaucoma, various optic neuropathies, retinal vascular diseases, and idiopathic intracranial hypertension using the PhNR (32)(33)(34)(35)(36)(37). In full-field ERG, the PhNR amplitude reflects cone-related RGC function and is significantly reduced with advancing visual field loss and reduced RNFL thickness as seen on OCT (38). The thinning of the RNFL typically follows the decreased PhNR amplitude, suggesting that functional changes precede structural abnormalities in the ganglions cells in LHON (38).…”

“…In full-field ERG, the PhNR amplitude reflects cone-related RGC function and is significantly reduced with advancing visual field loss and reduced RNFL thickness as seen on OCT (38). The thinning of the RNFL typically follows the decreased PhNR amplitude, suggesting that functional changes precede structural abnormalities in the ganglions cells in LHON (38). In summary, there is good evidence to suggest the use of clinical ERG including the PhNR and ocular imaging such as OCT in aiding the diagnosis and monitoring the severity of disease in patients with LHON.…”