Can Variability of Pattern ERG Signal Help to Detect Retinal Ganglion Cells Dysfunction in Glaucomatous Eyes?

Abstract

Objective. To evaluate variability of steady-state pattern electroretinogram (SS-PERG) signal in normal, suspected, and glaucomatous eyes. Methods. Twenty-one subjects with suspected glaucoma due to disc abnormalities (GS), 37 patients with early glaucoma (EG), and 24 normal control (NC) were tested with spectral-domain optical coherence tomography (SD-OCT), standard automated perimetry (SAP), and SS-PERG. Mean deviation (MD), pattern standard deviation (PSD), retinal nerve fiber layer (RNFL), and ganglionar complex cells (GCC) were evaluated. The SS-PERG was recorded five consecutive times and the amplitude and phase of second harmonic were measured. PERG amplitude and coefficient of variation of phase (CVphase) were recorded, and correlation with structural and functional parameters of disease, by means of one-way ANOVA and Pearson's correlation, was analysed. Results. PERG amplitude was reduced, as expression of retinal ganglion cells (RGCs) dysfunction, in EG patients and GS subjects compared to NC patients (P < 0.0001). CVphase was significantly increased in EG patients and GS subjects, compared to healthy (P < 0.0001), and it was also correlated with PSD (P = 0.0009), GCC (P = 0.028), and RNFL (P = 0.0078) only in EG patients. Conclusions. Increased intrasession variability of phase in suspected glaucomatous eyes may be a sign of RGCs dysfunction.

Steady‐state pattern electroretinogram and short‐duration transient visual evoked potentials in glaucomatous and healthy eyes

“…This difference in phase consistency is demonstrated in Figures c,d. A low ss‐PERG phase consistency and decreased amplitude have been previously seen in patients with glaucoma . Accordingly, we found MagnitudeD to be significantly lower in patients with glaucoma than in healthy controls.…”

RE-PERG, a new procedure for electrophysiologic diagnosis of glaucoma that may improve PERG specificity

“…We considered a low amplitude in SS-PERG (<1.5 μm) and a high phase variability of PERG signal in RE-PERG (>0.15 SD) as pathologic. 36 , 41 …”

“…A similar electrode placed on the lid of the unstimulated eye was used as a reference, as described in other studies. 36 In all cases, the impedance was below 5 k. The responses were amplified (gain of 100,000), filtered (bandwidth: 130 Hz), and sampled with a resolution of 12 bits. The analysis time was equal to the time period of the stimulus (133 ms).…”

“…In a previous study, 36 we showed that the individual-intrinsic within-trial variability of the PERG signal in test–retest of the same eye (ie, five consecutive stimulations without pause, a procedure that we called RE-PERG or REPERG) of early GP was greater than the physiologic one present in healthy individuals; in addition, it was also correlated with markers of disease severity such as retinal thickness and visual field indices. The aim of this study was to verify that such variations are not influenced by optic media opacities and, therefore, that the RE-PERG can be more reliable than the standard SS-PERG in the discrimination of GP.…”

Noninvasive Prenatal Diagnosis Significance of ERG Methylation as a Biomarker in Down’s Syndrome

“…Chromosome detection of amniotic fluid cells is an effective way to diagnose DS, but it has limitations, such as being a complicated process and it is time-consuming [ 12 , 13 ]. Noninvasive gene detection technique is a novel method for DS examination, and its theoretical basis is that blood of pregnant women contains genomic DNA of the fetus [ 14 – 16 ], which can help determine whether the fetus has trisomy 21 or ERG mutation by use of sequence comparative analysis based on DNA sequencing of the pregnant woman’s blood [ 17 ]. It is very difficult to detect a small amount of DNA from the fetus in the blood of a pregnant woman, which makes noninvasive gene detection difficult [ 18 ].…”