Pattern Electroretinogram Parameters Research Articles

Bilateral Pattern Electroretinogram Abnormalities in Patients with Herpes Zoster Keratitis and Conjunctivitis.

Herpes zoster ophthalmicus (HZO) results from the reactivation of varicella zoster virus (VZV) in the ophthalmic branch of the trigeminal nerve. The inflammation caused by VZV involves multiple tissues in the eyes. Our goal is to evaluate pattern electroretinogram (PERG) changes and their relationship with corneal sub-basal nerve changes in patients with HZO. Twenty-two patients with herpes zoster keratitis or conjunctivitis and 20 healthy volunteers were recruited for this cross-sectional study. A PERG test was performed on both eyes of HZO patients and one eye of the healthy controls. In vivo confocal microscopy (IVCM) was also performed on both eyes of the HZO patients to detect corneal nerve damage. Our results showed changes in the PERG parameters in both eyes of HZO patients compared to the healthy controls. Affected eyes showed delayed N95 peak time and decreased P50 and N95 amplitude compared to the unaffected eyes (p < 0.05, respectively). Both affected and unaffected eyes in HZO patients showed delayed P50 peak time and decreased N95 amplitude (p < 0.05, respectively) compared to controls. In HZO patients, no significant differences in each PERG parameter were found between eyes with and without corneal lesions or between eyes with and without increased Langham's cells in the corneal epithelial sub-basal layer. The IVCM images showed decreased total nerve length and number at the sub-basal layer of the epithelial cornea in affected eyes compared to unaffected eyes (p < 0.05). No significant correlation was found between total nerve length and PERG changes. Our results showed that VZV-affected eyes without central cornea involvement displayed reduced N95 amplitude and prolonged P50 peak time in bilateral eyes compared to the healthy controls. Larger studies are needed to further explore the effect of HZO on the electrophysiological response of the eye and the posterior segment.

Hemifield-based analysis of pattern electroretinography in normal subjects and patients with preperimetric glaucoma

This prospective cross-sectional study investigated the visual function of preperimetric glaucoma (PPG) patients based on hemifield (HF) pattern electroretinogram (PERG) amplitudes. Thirty-two (32) normal subjects and 33 PPG patients were enrolled in control and PPG groups, respectively. All of the participants had undergone full ophthalmic examinations, including spectral-domain optical coherence tomography (SD-OCT), visual field (VF) examination and pattern electroretinography (PERG). The PERG parameters along with the HF ratios of SD-OCT and PERG were compared between the control and PPG groups. Pairwise Pearson's correlation coefficients and linear regression models were fitted to investigate the correlations. The PERG N95 amplitudes were significantly lower in the PPG group (P < 0.001). The smaller/larger HF N95 amplitude ratio of the PPG group was found to be smaller than that of the control group (0.73 ± 0.20 vs. 0.86 ± 0.12; P = 0.003) and showed positive correlations with affected HF average ganglion cell-inner plexiform layer (GCIPL) thickness (r = 0.377, P = 0.034) and with average GCIPL thickness (r = 0.341, P = 0.005). The smaller/larger HF N95 amplitude ratio did not significantly change with age (β = − 0.005, P = 0.195), whereas the full-field N95 amplitude showed a negative correlation with age (β = − 0.081, P < 0.001). HF analysis of PERG N95 amplitudes might be particularly useful for patients with early glaucoma.

Retinal Ganglion Cell Functional Recovery after Intraocular Pressure Lowering Treatment Using Prostaglandin Analogs in Glaucoma Suspects: A Prospective Pilot Study.

To evaluate the ability of pattern electroretinogram (PERG) to detect improvement of retinal ganglion cell (RGC) function in glaucoma suspects (GS) after medically reducing intraocular pressure (IOP) using prostaglandin analog drops. Six subjects (eight eyes) received topical IOP lowering treatment based on their clinical examination and were observed at Manhattan Eye, Ear & Throat Hospital over an average of 3.1 ± 2.2 months. During this time, participants underwent a full ophthalmologic exam and were evaluated with a Humphrey visual field analyzer (HFA) 24-2 [24-2 mean deviation (MD), 24-2 pattern standard deviation (PSD), and 24-2 visual field indices (VFI)], Diopsys NOVA PERG optimized for glaucoma [magnitude (Mag), magnitudeD (MagD), and magnitudeD/magnitude ratio (MagD/Mag ratio)] and optical coherence tomography (OCT)-derived average retinal nerve fiber layer thickness (avRNFLT) and average ganglion cell layer + inner plexiform layer (avGCL + IPL) thicknesses at baseline visit (pretreatment) and 3 months later (posttreatment). Goldman applanation tonometry was used to measure IOP at each visit. Paired sample t-tests were conducted to determine the statistical significance of the change in IOP, HFA indices, PERG parameters, and OCT thickness measurements between the two visits. Lowering IOP by 22.29% resulted in a significant increase (32.98 and 15.49%) in MagD [t (7) = -3.174, 95% confidence interval (CI) = -0.53, -0.08, p = 0.016] and MagD/Mag ratio [t (7) = -3.233, 95% CI = -0.20, -0.03, p = 0.014], respectively. There was a positive percentage change for all variables of interest, however, 24-2 MD, Mag, avRNFLT, and GCL+ IPLT did not reach statistical significance. After reducing IOP by 22.29% for a duration of 3.1 months, the PERG parameters, MagD and MagD/Mag ratio, significantly improved by 32.98 and 15.49%, respectively. Pattern electroretinogram (PERG) may be a crucial tool for clinicians to locate a window of opportunity in which degenerating yet viable RGCs could be rescued from irreversible damage. We suggest consideration of PERG as a tool in early retinal ganglion cell (RGC) dysfunction detection as well as for monitoring IOP lowering treatment. Tirsi A, Gliagias V, Sheha H, et al. Retinal Ganglion Cell Functional Recovery after Intraocular Pressure Lowering Treatment Using Prostaglandin Analogs in Glaucoma Suspects: A Prospective Pilot Study. J Curr Glaucoma Pract 2023;17(4):178-190.

Hypotensive therapy effectiveness evaluation in primary open-angle glaucoma evidenced by pattern electroretinogram data

Purpose. To evaluate the change in the functional activity of retinal ganglion cells (RGCs) in response to intraocular pressure (IOP) drop in patients with newly diagnosed early stage primary open-angle glaucoma (POAG) using a pattern electroretinogram (PERG). Material and methods. A prospective non-randomized cohort study included 12 patients (24 eyes) including 5 men, 7 women, aged 63.42 ± 2.96 years with newly diagnosed early stage POAG in at least one eye, who underwent PERG (Diopsys Nova, Diopsys, Inc.) in addition to an ophthalmologic examination. After being diagnosed with POAG, all patients were prescribed prostaglandin analogues as monotherapy. One and four months into the treatment, repeated examinations took place. Results. At these time points, a significant decrease in IOP was noted, accompanied by an increase in PERG parameters , which indicates an improvement in the functional activity of RGCs, yet no linear relationship between the IOP decrease and the improvement in PERG parameters could be found. Conclusion. Early stage naïve-treatment POAG patients with minimally impaired visual fields as determined by threshold computer perimetry may have their RGCs functional activity partially restored and IOP lessened thanks to continuous IOP-lowering therapy with prostaglandin analogues. PERG can be used as a method for evaluating the effectiveness of glaucoma hypotensive therapy in terms of maintaining and improving the functional activity of RGCs.

Pattern Electroretinogram Parameters and their Associations with Optical Coherence Tomography in Glaucoma Suspects.

AimTo investigate whether steady state pattern electroretinogram (ssPERG) could identify retinal ganglion cell (RGC) dysfunction, and to assess the relationship between ssPERG with optical coherence tomography (OCT) measurements in glaucoma suspects (GS).Materials and methodsThis was a prospective cohort study of GS, identified based on suspicious optic disk appearance and glaucoma risk factors. Complete eye exam, Standard automated perimetry, OCT, and ssPERG were performed. Magnitude (Mag), Magnitude D (MagD), and MagD/Mag ratio were subsequently used in the correlation and linear regression analyses between ssPERG parameters and the RNFL, GCL/IPL, and macular thicknesses measurements.ResultsForty-nine eyes of 26 patients were included. Mag and MagD were significantly correlated with the superior, inferior, and average RNFL thicknesses (avRNFLT). All ssPERG parameters were significantly correlated with the average and minimum GCL/IPL thicknesses and the inner macular sector thicknesses. Mag and MagD significantly predicted the superior, inferior, and avRNFLT in the regression analysis. All ssPERG parameters were predictive of GCL/IPL thickness in all sectors as well as the average and minimum GCL/IPL thicknesses. All ssPERG parameters were predictive of all inner macular sector thicknesses and MagD was also predictive of some outer macular sector thicknesses as well.ConclusionssPERG has significant correlations with and is predictive of RNFL, GCL/IPL, and macular thicknesses in glaucoma suspects.Clinical significancessPERG may serve as a useful objective functional tool for identifying and following the progression of disease in glaucoma suspects.How to cite this articleTirsi A, Wong A, Zhu D, et al. Pattern Electroretinogram Parameters and their Associations with Optical Coherence Tomography in Glaucoma Suspects. J Curr Glaucoma Pract 2022;16(2):96-104.

Pattern Electroretinogram Parameters Are Associated with Optic Nerve Morphology in Preperimetric Glaucoma after Adjusting for Disc Area.

Purpose We examined the relationships between pattern electroretinogram and optical coherence tomography derived optic nerve head measurements, after controlling for disc area. Methods Thirty-two eyes from 20 subjects with preperimetric glaucoma underwent pattern electroretinogram and optical coherence tomography. Pattern electroretinogram parameters (Magnitude, MagnitudeD, and MagnitudeD/Magnitude ratio) and optic nerve head measurements (rim area, average cup to disc ratio, vertical cup to disc ratio, cup volume, retinal nerve fiber layer thickness sectors, and Bruch's membrane opening-minimum rim width thickness sectors) were analyzed after controlling for disc area. Results Magnitude and MagnitudeD were significantly associated with rim area (r ≥ 0.503, p ≤ 0.004). All pattern electroretinogram parameters significantly correlated with Bruch's membrane opening-minimum rim width sectors—temporal superior and nasal inferior (r = 0.400, p=0.039)—and retinal nerve fiber layer sectors—superior, nasal superior, and inferior (r ≥ 0.428, p ≤ 0.026). Magnitude and MagnitudeD explained an additional 26.8% and 25.2% of variance in rim area (B = 0.174 (95% CI: 0.065, 0.283), p=0.003, and B = 0.160 (95% CI: 0.056, 0.265), p=0.004), respectively. MagnitudeD and MagnitudeD/Magnitude ratio explained an additional 13.4% and 12.8% of the variance in Bruch's membrane opening-minimum rim width global (B = 38.921 [95% CI: 3.872, 73.970], p=0.031, and B = 129.024 (95% CI: 9.589, 248.460), p=0.035), respectively. All Bruch's membrane opening-minimum rim width sectors and retinal nerve fiber layer sectors (nasal superior, nasal inferior, and inferior) were significantly correlated with rim area (r ≥ 0.389, p ≤ 0.045). Conclusion PERG abnormalities can predict rim area loss in preperimetric glaucoma after controlling for disc area. We recommend controlling for disc area to increase diagnostic accuracy in early glaucoma.

The role of pattern electroretinograms and optical coherence tomography angiography in the diagnosis of normal-tension glaucoma

In this study, we investigated the correlation between pattern electroretinogram (PERG) and optical coherence tomography angiography (OCTA) parameters for diagnosis in patients with normal-tension glaucoma (NTG). Forty-nine normal individuals (49 eyes) and 60 patients with NTG (60 eyes) were enrolled. OCTA and PERG parameters, such as macular vessel density (VD) and the amplitude of N35–P50 and P50–N95, were measured. Correlation analyses were performed between the parameters, and the area under the curve (AUC) was used to identify their diagnostic ability for NTG. Macular VD and the amplitude of N35–P50 and P50–N95 showed significant differences between the normal individuals and patients with NTG. Correlation between P50 and N95 amplitude and macular VD was significant in the normal and early glaucoma groups. Macular VD showed a higher AUC value (0.730) than that of P50–N95 amplitude (0.645) in the early glaucoma group. In the moderate to severe glaucoma group, the AUC value of the amplitude of P50–N95 (0.907) was higher than that of macular VD (0.876). The results indicate that PERG and OCTA parameters may identify glaucoma in its early stage, based on the severity of glaucomatous damage in patients with NTG.

Pattern Electroretinograms in Preperimetric and Perimetric Glaucoma

To investigate whether visual function can be graded in detail using pattern electroretinogram (PERG) in preperimetric to perimetric glaucoma. Cross-sectional observational study. Twenty-six normal subjects, 113 preperimetric glaucoma patients (which included glaucoma suspect patients), and 52 early perimetric glaucoma patients with a mean deviation (MD) >-10 dB were included. Structural and functional measurements were performed using spectral-domain optical coherence tomography and a commercial ERG stimulator, respectively. The average retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness were thinnest in the perimetric group, followed by the preperimetric group and the control group (P < .001). PERG N95 amplitude was the largest in the control group, followed by the preperimetric group and the perimetric group (P < .001). Among the preperimetric glaucoma patients, presence of the RNFL defect was associated with lower PERG N95 amplitude (P= .013). The N95 amplitude showed a significant relationship with average RNFL thickness (r= 0.336, P < .001) and GCIPL thickness (r= 0.376, P < .001). In the preperimetric group with the RNFL defect, the N95 amplitude showed larger areas under the receiver operating characteristic curve (0.779) than the MD (0.533, P= .005). PERG N95 amplitudes decreased from the control to preperimetric glaucoma group and were reduced more in perimetric glaucoma. The functional assessment for detecting early glaucomatous damage could be complemented by PERG N95 amplitude. Usefulness of PERG parameters except N95 amplitude seemed to be limited in a clinical setting because of relatively low diagnostic performance in preperimetric glaucoma.

Early detection of neurodegeneration in type 2 diabetic patients without diabetic retinopathy using electroretinogram and spectral-domain optical coherence tomography

Purpose The aim was to assess early functional and structural changes in the neural retina in type 2 diabetic patients with no clinical signs of diabetic retinopathy (DR). Patients and methods A total of 92 eyes of 48 patients were included, which were divided into the following groups: 30 eyes of 16 participants with type 2 diabetes mellitus without clinical DR, with a mean age of 48.75±3.09 years, as group 1; 30 eyes of 16 participants with type 2 diabetes mellitus with DR, with a mean age of 51.75±2.86 years, as group 2; and a control group of 32 eyes of 16 healthy age-matched and sex-matched participants, with a mean age of 49.88±4.26 years. After full ophthalmologic examination, spectral-domain optical coherence tomography scans, multifocal electroretinogram (Mf-ERG), pattern electroretinogram (PERG), and photonegative response (PhNR) were tested for all participants. Statistical analysis was performed to compare ganglion cell complex (GCC) thicknesses, multifocal electroretinogram, PERG, and phNR values between the groups. Results There were no statistically significant differences between the studied groups regarding age, sex, refraction, or intraocular pressure (P=0.056,0.72, 0.16, and 0.35, respectively). There were significant differences of total GCC thickness values among group 1 (107.13±7.04 μm), group 2 (97.27±10.97 μm), and control group (113.81±5.26 μm) (P Conclusion The preclinical DR presents with neural loss in the macular area, evident by the reduction GCC thickness and impairments of mf-ERG, PERG, and phNR parameters. Neurodegenerative changes precede the microvascular damage in these patients.

Evaluation of Retinal Nerve Fiber Layer Thickness, Electroretinogram and Visual Evoked Potential in Patients with Alzheimer's Disease.

Objective To study the retinal nerve fibre layer (RNFL) thickness and visual electrophysiology testing in patients with Alzheimer's disease (AD). Methods A cross-sectional, hospital-based study: 25 AD subjects and 25 controls were recruited. Candidates who fulfil the criteria with normal ocular examinations were made to proceed with scanning laser polarimetry, pattern electroretinogram (PERG), and pattern visual evoked potential (PVEP) examinations of the right eye. RNFL thickness, PERG, and PVEP readings were evaluated. Results In AD, the mean of average RNFL thickness was 45.28 μm, SD = 3.61, P < 0.001 (P < 0.05), while the superior RNFL thickness was 54.44 μm, SD = 2.85, P < 0.001 (P < 0.05) and inferior RNFL thickness was 47.11 μm, SD = 4.52, P < 0.001 (P < 0.05). For PERG, the mean P50 latency was 63.88 ms, SD = 7.94, P < 0.001 (P < 0.05) and the mean amplitudes of P50 waves were 1.79 μV, SD = 0.64, P < 0.001 (P < 0.05) and N95 waves were 2.43 μV, SD = 0.90, P < 0.001 (P < 0.05). For PVEP, the mean latency of P100 was 119.00 ms, SD = 9.07, P < 0.001 (P < 0.05), while the mean latency of N135 was 145.20 ms, SD = 8.53, P < 0.001 (P < 0.05). The mean amplitude of P100 waves was 3.71 μV, SD = 1.60, P < 0.001 (P < 0.05), whereas the mean amplitude of N135 waves was 3.67 μV, SD = 2.02, P < 0.001 (P < 0.05). RNFL thickness strongly correlates with PERG readings, with P50 latency R = 0.582, R2 = 0.339, P=0.002 (P < 0.05), amplitude of P50 wave at R = 0.749, R2 = 0.561, P ≤ 0.001 (P < 0.05), and amplitude of N95 wave at R = 0.500, R2 = 0.250, P=0.011 (P < 0.05). No significant difference and correlation were observed on PVEP readings. Conclusion The mean of the average, superior and inferior RNFL thickness were significantly lower in the AD group compared with control. There is also significant difference of PERG and PVEP parameters between AD and controls. Regression analysis showed average RNFL thickness having significantly linear relationship with the PERG parameters.

Reduced pattern electroretinogram signal in affected patients with Leber Hereditary Optic Neuropathy

AbstractPurposeThe pattern electroretinogram (PERG) signal has been reported to be a sensitive tool for the detection of retinal ganglion cell (RGC) dysfunction in both animal models and patients suffering from optic neuropathies. This study investigated whether functional PERG can detect different levels of RGC dysfunction in both carriers and affected patients with Leber Hereditary Optic Neuropathy (LHON).MethodsPERG signals were recorded using both checkerboard (0.8° check size, 2 reversals/sec) and bars (0.5 cycles/deg) stimuli with mean luminance of 300 cd/m2 and 100% contrast. PERG signals were measured against functional full field Photopic Negative Response (PhNR) recordings (red flashes at 5 cd s/m2 stimulus intensity on blue rod saturating background) and subjective measures of retinal sensitivity (mean deviation [MD] via 30‐2 automated visual fields) and structural metrics (both ganglion cell complex [GCC] and retinal nerve fiber layer [RNFL] thickness from optical coherence tomography [OCT] scans).ResultsPERG P50 amplitudes were similar across controls, carriers, and LHON affected patients. P50 implicit times were significantly reduced in LHON affected patients (CHECKS: 45.8 ± 1.1 ms; BARS: 43.5 ± 0.8 ms; n = 32) compared to controls (CHECKS: 49.3 ± 0.5 ms; BARS: 48.1 ± 0.4 ms; n = 72). N95 amplitudes elicited by the checkerboard stimulus were significantly reduced and implicit times significantly increased in LHON affected patients (−3.4 ± 0.4 µV; 93.6 ± 2.2 ms; n = 32) compared to controls (−5.9 ± 0.5 µV; 85.3 ± 0.8 ms; n = 72). No differences were seen in PERG signals between control or LHON affected patients and carriers. Although PERG parameters were significantly different in LHON affected patients, the measurements were not correlated with PhNR signals, MD and RNFL thickness in all four quadrants around the optic disc. On the other hand, PhNR amplitudes, which were significantly reduced in LHON affected (−16.3 ± 3.4 µV; n = 32) and in carriers (−21.8 ± 3.0 µV; n = 30) compared to controls (−34.2 ± 2.5 µV; n = 28), were correlated with MD (r = −0.611, p &lt; 0.0005; n = 28), average GCC (r = −0.618, p &lt; 0.0001; n = 32) and average RNFL thickness (r = −0.553, p &lt; 0.001; n = 31) in affected patients.ConclusionsSignificant differences in PERG recordings were measured between control and LHON affected patients. However, no significant differences were seen in carriers and PERG metrics were not correlated with functional PhNR parameters and other subjective and objective measurements tested. Our results suggest that PERG may not be as sensitive as PhNR to discriminate different levels of RGC dysfunction between LHON affected patients and carriers.

Test-retest repeatability of the pattern electroretinogram and flicker electroretinogram.

To evaluate the repeatability of the steady-state pattern electroretinogram (PERG) and full-field flicker electroretinogram (Flicker ERG) protocols, delivered by the office-based Neuro Optic Vision Assessment (NOVA)™ testing platform, in healthy subjects. Healthy individuals underwent PERG (16° and 24°) and Flicker ERG [fixed luminance (FL) and multi-luminance (ML)] testing protocols. Test-retest repeatability of protocols was calculated using intra-class correlation coefficients (ICC). Reference values of the parameters of the aforementioned tests were also calculated. The ICCs for the PERG parameters ranged from 0.793 to 0.911 (p < 0.001). The ICCs for the Flicker ERG parameters ranged from 0.968 to 0.994 (p < 0.001). A linear regression analysis was applied to assess the impact of age on ERG responses. Age had a significant impact on all PERG parameters (16° or 24°). The phase response of the FL Flicker ERG significantly decreased with age (β = - 0.837, p ≤ 0.001). The FL Flicker ERG Magnitude was also impacted with a significant quadratic effect of age (β = - 0.0047, p = 0.0004). Similarly, the Phase Area Under the Curve (Phase AUC) of the ML Flicker ERG significantly declined with age (β = - 0.007, p = 0.009), and the impact on the Magnitude AUC was significant as well, with a negative quadratic age effect. The PERG and Flicker ERG protocols, delivered by an office-based testing platform, were shown to have good-to-excellent test-retest repeatability when tests were performed in the same order and in immediate succession.

Role of Pattern Electroretinogram in Ocular Hypertension and Early Glaucoma.

To test whether pattern electroretinogram (PERG) can early detect retinal ganglion cells dysfunction in ocular hypertension. Cross-sectional observational study. The study included 3 groups: control, primary open-angle glaucoma (POAG) and ocular hypertension (OHT) groups with 30 eyes in each group. Visual fields were examined using automated perimetry with central 24-2 program. Optical coherent tomography (OCT) was done to assess the neuroretinal rim area, vertical cup/disc ratio, and average superior and inferior retinal nerve fiber layer thickness. PERG was recorded using skin electrodes. Amplitude and latency of P50 and N95 were documented. PERG data: the mean P50 and N95 latency were significantly higher in the POAG group and the OHT group compared with the control group (P<0.001, <0.001, respectively). Also, the mean P50 and N95 amplitude were significantly lower in the POAG group and the OHT group compared with the control group (P<0.001,<0.001, respectively). In the POAG group, there was a significant negative correlation between PSD on one hand and P50 amplitude (r=-0.620, P=0.001) and N95 amplitude (r=-0.61, P<0.001) on the other hand. Also, the mean deviation was positively correlated with P50 amplitude (r=0.51, P=0.007) and N95 amplitudes (r=0.50, P=0.002). However, there was no significant correlation between PERG parameters and OCT parameters. In the OHT group, PERG parameters did not correlate with visual field and OCT parameters. PERG can detect the dysfunctional, but still live retinal ganglion cells earlier than OCT in OHT cases, allowing the early start of treatment that can restore the ganglion cell function before irreversible damage occurs.

Efficacy of N95 amplitude of pattern electroretinogram measured from baseline to N95 trough in the traumatic optic neuropathy.

To investigate the utility of selected pattern electroretinogram (PERG) parameters-including N95 amplitude and N95/P50 ratio, and a BL-N95 amplitude-in the analysis of visual function(s) and for predicting changes in retinal ganglion cell structures in traumatic optic neuropathy. A retrospective, observational case series performed at a single center. Forty-four eyes from 36 patients diagnosed with optic neuropathy were included. A BL-N95 amplitude was defined as the amplitude measured from baseline to the trough of N95. PERG and pattern visual evoked potential (pVEP) measures were acquired within 1week after onset of optic neuropathies. To compare functional and anatomical changes, mean temporal peripapillary retinal nerve fiber layer (pRNFL) and average and minimum ganglion cell-inner plexiform layer (GC-IPL) thicknesses were measured using optical coherence tomography. Thirty-six patients (20 men, 16 women; mean age 37.5 ± 17.6years) were evaluated. The BL-N95 amplitude was significantly smaller than the N95 amplitude (1.01 ± 0.56μV and 2.45 ± 1.02μV, respectively; p < 0.0001). Both the N95 (r = - 0.38, p = 0.010) and BL-N95 r = - 0.32, p = 0.029) amplitudes were significantly correlated with visual acuity. Although P100 latency was not correlated with all PERG parameters, the N95 (r = 0.32, p = 0.032) and BL-N95 (r = 0.41, p = 0.005) amplitudes demonstrated a positive correlation with P100 amplitude in pVEP. PERG parameters, including the N95 and BL-N95 amplitudes, and N95/P50 ratio, were not correlated with pRNFL thickness in optical coherence tomography. Only the BL-N95 amplitude demonstrated a significant correlation with GC-IPL. The BL-N95 amplitude-measured from baseline to the trough of N95-was valuable in the analysis of visual function(s) and for predicting changes in retinal ganglion cell structures in traumatic optic neuropathy.

Functional Changes of Retinal Ganglion Cells and Visual Pathways in Patients with Chronic Leber’s Hereditary Optic Neuropathy during One Year of Follow-up

To assess changes of retinal ganglion cells (RGCs) and visual pathways' function in patients with Leber's hereditary optic neuropathy (LHON) during 12 months of follow-up of the chronic phase. Retrospective case series. Twenty-two patients with LHON (mean age, 36.3±9.3 years) in the "chronic phase" of the disease, providing 42 eyes (LHON group) with different pathogenic mitochondrial DNA mutations (group 11778: 21 eyes; group 3460: 4 eyes; group 14484: 13 eyes; and group 14568: 4 eyes) were enrolled. Twenty-five age-similar healthy participants, providing 25 eyes, served as controls. Pattern electroretinogram (PERG) and visual evoked potentials (VEP), in response to 60' and 15' checks visual stimuli, were recorded at baseline in all subjects and after 6 and 12 months of follow-up in patients with LHON. At baseline, in all LHON eyes for each PERG and VEP parameter (amplitude and implicit time), the 95% confidence limit (CL) of test-retest variability was calculated. The PERG and VEP mean values observed in LHON eyes were compared (1-way analysis of variance [ANOVA]) with those of controls. During the follow-up, the PERG and VEP differences observed with respect to baseline were evaluated by ANOVA. Changes of individual and mean absolute values of 60' and 15' PERG amplitude and VEP amplitude and implicit time at each time point compared with baseline values in the LHON group. At baseline, mean values of PERG and VEP parameters detected in the LHON group were significantly (P < 0.01) different with respect to control values. In the LHON group, at 6 and 12 months of follow-up, the majority of eyes showed unmodified (within 95% CL) PERG and VEP values, and mean absolute values of these measures were not significantly (P > 0.01) different from baseline values. In our untreated patients with chronic LHON, with different specific pathogenic mutations, RGCs and visual pathways function were not significantly modified during 12 months of follow-up. This should be considered in the disease natural history when attempts for treatments are proposed in chronic LHON.

Early detection of glaucoma suspect by pattern electroretinogram

Aim This study was intended to estimate the significance of pattern electroretinogram (PERG) in evaluation of the retinal ganglion cell function in patients with glaucoma. Patients and methods An observational case–control study was done on 40 eyes of individuals whose age ranged between 30 and 65 years of age. They were divided into two equal groups. Control group had normal visual field and optical coherence tomography optic nerve, intraocular pressure (IOP) less than 21 mmHg, visual acuity more than 0.3, and cup disc ratio (C/D) less than 0.5. The case group was divided into two equal subgroups: group A had IOP more than 21 mmHg and C/D less than 0.5, and group B had IOP less than 21 mmHg and C/D more than 0.5. We excluded all cases with ocular or systemic diseases with negative effect on retinal function such as retinal detachment, retinitis pigmentosa, rheumatoid arthritis on hydroxychloroquine, diabetic patients on insulin or oral hypoglycemic, or cases with abnormal optic disc appearance such as optic disc drusen, coloboma, or tilted disc. All cases underwent full ophthalmological examination, including best-corrected visual acuity, complete anterior segment examination with slit-lamp biomicroscopy, and posterior segment examination using volk 90 D lens, along with IOP measurement using Goldmann applanation tonometer. Visual field assessment was done using Heidelberg Edge Perimeter, optical coherence tomography optic nerve using Heidelberg engineering, and glaucoma screening with ERG using glaucoma screening program. Results There was a highly statistically significant difference between the groups regarding C/D and IOP. Regarding the PERG and different visual fields parameters, there was a highly statistically significant difference between the groups. There was a statistically significant negative correlation between PERG and both IOP and VF parameters in all different groups. No statistically significant correlation was found between PERG and C/D in all different groups. Conclusion PERG has a prognostic value in recognition of retinal ganglion cell dysfunction, as an early indication for glaucoma development.

Macular and Multifocal PERG and FD-OCT in Preperimetric and Hemifield Loss Glaucoma.

To evaluate the ability of macular and multifocal (mf) pattern electroretinogram (PERG) to differentiate preperimetric glaucoma (PG) and glaucoma with hemifield loss (GHL) from controls, to compare the discrimination ability of PERG and fourier-domain optical coherence tomography (FD-OCT), and to assess the relationship between measurements. Standard automated perimetry, steady-state and transient PERG and mfPERG measurements were obtained from PG (n=14, 24 eyes), GHL (n=5, 7 eyes), and controls (n=19, 22 eyes). Circumpapillary retinal nerve fiber layer (cpRNFL), full-thickness macula, and segmented macular layer thicknesses on FD-OCT were investigated. Measurements were compared using mixed effects linear models. The relationships between measurements and the diagnostic performance of each technology were assessed. Compared with controls, average P50 peak time transient PERG responses were reduced in PG and GHL, whereas average latency and amplitude steady-state and mfPERG responses were abnormal only in GHL. cpRNFL and macular thickness measurements in PG and GHL differed significantly from controls. A significant relationship was found between PERG and most FD-OCT or SAP parameters. Partial least squares discriminant analysis revealed that OCT parameters, along with mfPERG and transient PERG parameters had similar ability to discriminate PG and GHL from healthy controls. PERG and OCT parameters may be abnormal, with significant correlations between measurements, in PG eyes. Both technologies may be useful for detection of early glaucoma.

Evaluation of retinal ganglion cell function after intraocular pressure reduction measured by pattern electroretinogram in patients with primary open-angle glaucoma

Background To evaluate retinal ganglion cell (RGC) function after intraocular pressure (IOP) reduction measured by pattern electroretinogram (PERG) in patients with newly diagnosed, non-treated preperimetric and early stages of primary open-angle glaucoma (POAG).MethodsTwenty-four eyes from 24 patients with POAG: 11 eyes with preperimetric glaucoma and 13 eyes with early glaucoma received Ganfort® (bimatoprost + timolol) once a day for a period of 1 month. Before and after the treatment, following measurements were analyzed: IOP, mean ocular perfusion pressure (MOPP), peak time of P50 and amplitude of P50 and N95 waves in PERG (ISCEV standard 2012). Correlations between PERG P50 and N95 waves, IOP and MOPP were calculated.ResultsAfter therapy, IOP significantly decreased in all eyes, on average 31%. Significant increase in MOPP in all eyes on average 14% was detected. PERG amplitude of P50 and N95 waves increased in 75 and 79% eyes, respectively, on average P50 by 28% and N95 by 38%. There were no significant interactions between the change of PERG parameters in time and stage of glaucoma.ConclusionsSignificant IOP-lowering therapy can improve RGC function measured by PERG, in patients with preperimetric and early stages of POAG.

Association between Asymptomatic Unilateral Internal Carotid Artery Stenosis and Electrophysiological Function of the Retina and Optic Nerve.

Purpose. This study was designed to assess retinal and optic nerve bioelectrical function in patients with unilateral asymptomatic but hemodynamically significant internal carotid artery stenosis (ICAS). Methods. Forty-two subjects with a diagnosis of unilateral ICAS and 34 controls were analyzed. Full-field electroretinogram (ERG), pattern electroretinogram (PERG), and pattern visual-evoked potentials, as well as optical coherence tomography and ophthalmological examination, were performed. Data analysis included eyes ipsilateral to ICAS (EIS) and eyes contralateral to ICAS (ECS). Results. Intraocular pressure was significantly decreased in EIS and ECS compared to that in the controls. In the macula, both the cube average thickness and cube volume values were significantly reduced both in EIS and ECS compared to those in the controls. Similarly, PERG P50 and N95 wave amplitudes were significantly smaller in EIS and ECS compared to those in the controls. The ERG rod b-wave and rod-cone a-wave amplitudes were decreased, and implicit times were significantly prolonged, whereas the OP wave index was reduced in EIS compared to that in the controls. No differences in IOP, OCT, or ERG and PERG parameters were identified between EIS and ECS. Conclusions. Our study demonstrated that retinal bioelectrical function is negatively affected by ICAS despite the absence of objective clinical signs and symptoms of ocular ischemia.

Effects of coenzyme Q10 in conjunction with vitamin E on retinal-evoked and cortical-evoked responses in patients with open-angle glaucoma.

To evaluate pattern-evoked retinal and cortical responses [pattern electroretinogram (PERG) and visual-evoked potential (VEP), respectively] after treatment with coenzyme Q10 in conjunction with vitamin E in open-angle glaucoma (OAG) patients. Forty-three OAG patients (mean age, 52.5±5.29 y; intraocular pressure <18 mm Hg with β-blocker monoterapy only) were enrolled. At baseline and after 6 and 12 months, simultaneous recordings of PERG and VEPs were obtained from 22 OAG patients who underwent treatment consisting of coenzyme Q10 and vitamin E (Coqun, 2 drops/d) in addition to β-blocker monoterapy (GC group), and from 21 OAG patients who were only treated with β-blockers (GP group). At baseline, intraocular pressure, PERG, and VEP parameters were similar in both GC and GP groups (analysis of variance, P>0.05). After 6 and 12 months, PERG and VEP response parameters of GP patients were unchanged when compared to baseline. In GC patients, PERG P50 and VEP P100 implicit times were decreased, whereas PERG P50-N95 and VEP N75-P100 amplitudes were increased (P<0.01) when compared to baseline. In the GC group, the differences in implicit times and amplitudes with respect to baseline were significantly larger (P<0.01) than those recorded in the GP group. The improvement (12 mo minus baseline) of VEP implicit time was significantly correlated with the changes of PERG P50-N95 amplitude (r=-0.66171, P=0.0008) and P50 implicit time (r=0.68364, P=0.00045) over a period of 12 months. Coenzyme Q10 associated with vitamin E administration in OAG shows a beneficial effect on the inner retinal function (PERG improvement) with consequent enhancement of the visual cortical responses (VEP improvement).