Test-retest repeatability of the pattern electroretinogram and flicker electroretinogram

Retinal Toxicity Assessment Following Vitreoretinal Surgery: A Comparison of Silicone Oil and Perfluoropropane Tamponade Using Diopsys® NOVA™

PURPOSE

This study aimed to assess and compare the retinal toxicity associated with silicone oil (SO) and perfluoropropane (C3F8) tamponade following vitreoretinal surgery for fresh rhegmatogenous retinal detachment (RRD), utilizing the office-based Diopsys® NOVA™ system for evaluation.

METHODS

Patients who underwent vitreoretinal surgery for fresh RRD and had SO (group 1) or C3F8 (group 2) tamponade were included in a prospective analysis. Flicker full field electroretinography (ffERG) and pattern electroretinography (PERG) tests were performed at 6 months postoperatively.

RESULTS

Postoperative best corrected visual acuity (logMAR) was significantly different in group 1 and group 2 patients, 0.48 ± 0.3 and 0.30 ± 0.2, respectively. No significant disparities were found in demographic variables. Flicker ffERG and PERG recordings revealed notable alterations in retinal function parameters in the group 1 compared to the group 2.

CONCLUSION

Our findings suggest a correlation between SO tamponade and retinal dysfunction, evidenced by office-based ERG measurements. The Diopsys® NOVA™ protocol offers clinical ease in assessing retinal function. Further controlled studies are essential to validate these findings and guide clinical practice effectively.

Evaluation of correlation between Diopsys® NOVA™ fixed-luminance flicker ERG and Diagnosys® Espion 2™ flicker ERG parameters

PURPOSE

Diopsys® NOVA™ is a novel full-field electroretinography (ffERG) device that can make rapid measurements of retinal electrophysiologic function. Diagnosys® Espion 2™ is a clinical gold-standard ERG device. This study aimed to investigate whether light-adapted Diopsys® NOVA™ fixed-luminance flicker ffERG magnitude and implicit time (converted from phase) measurements correlate with light-adapted Diagnosys® Espion 2™ flicker ffERG amplitude and implicit time measurements, respectively.

METHODS

Twelve patients (22 eyes) with various retinal and uveitic diseases underwent light-adapted Diagnosys® Espion 2™ and Diopsys® NOVA™ fixed-luminance flicker testing. Diopsys® magnitude and implicit time (converted from phase) measurements were compared to Diagnosys® amplitude and implicit time measurements, and a Pearson correlation was used to evaluate any existing correlation. Groups were also compared using generalized estimating equations. Bland-Altman plots were utilized to determine agreement between the comparison groups.

RESULTS

Age of patients ranged from 14 to 87 years. 58% (n = 7/12) of patients were female. A significant, positive correlation (r = 0.880, P < 0.001) was observed between magnitude (Diopsys®) and amplitude (Diagnosys®) measurements. Amplitude increases by 6.69 µV for each 1 µV increase in Magnitude (p-value < 0.001). A statistically significant, strong positive correlation was observed between Diopsys® implicit time measurements (converted from phase) and Diagnosys® implicit time measurements (r = 0.814, p-value < 0.001). For each 1 ms increase in Diopsys® implicit time, Diagnosys® implicit time increases by 1.13 ms (p-value < 0.001).

CONCLUSIONS

There is a statistically significant positive correlation between light-adapted Diopsys® NOVA™ fixed-luminance flicker amplitude and Diagnosys® flicker magnitude values. Additionally, there is a statistically significant positive correlation between Diopsys® NOVA™ fixed-luminance flicker implicit time (converted from phase) and Diagnosys® flicker implicit time values. These results imply that the Diopsys® NOVA™ module, which utilizes the nonstandard shortened International Society for Clinical Electrophysiology of Vision (ISCEV) ERG protocol, can produce reliable light-adapted flicker ffERG measurements.

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

Aim

To 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 methods

This 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.

Results

Forty-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.

Conclusion

ssPERG has significant correlations with and is predictive of RNFL, GCL/IPL, and macular thicknesses in glaucoma suspects.

Clinical significance

ssPERG may serve as a useful objective functional tool for identifying and following the progression of disease in glaucoma suspects.

How to cite this article

Tirsi 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.

Aging effects on contrast sensitivity in visual pathways: A pilot study on flicker adaptation

Contrast sensitivity is reduced in older adults and is often measured at an overall perceptual level. Recent human psychophysical studies have provided paradigms to measure contrast sensitivity independently in the magnocellular (MC) and parvocellular (PC) visual pathways and have reported desensitization in the MC pathway after flicker adaptation. The current study investigates the influence of aging on contrast sensitivity and on the desensitization effect in the two visual pathways. The steady- and pulsed-pedestal paradigms were used to measure contrast sensitivity under two adaptation conditions in 45 observers. In the non-flicker adaptation condition, observers adapted to a pedestal array of four 1°×1° squares presented with a steady luminance; in the flicker adaptation condition, observers adapted to a square-wave modulated luminance flicker of 7.5 Hz and 50% contrast. Results showed significant age-related contrast sensitivity reductions in the MC and PC pathways, with a significantly larger decrease of contrast sensitivity for individuals older than 50 years of age in the MC pathway but not in the PC pathway. These results are consistent with the hypothesis that sensitivity reduction observed at the overall perceptual level likely comes from both the MC and PC visual pathways, with a more dramatic reduction resulting from the MC pathway for adults >50 years of age. In addition, a similar desensitization effect from flicker adaptation was observed in the MC pathway for all ages, which suggests that aging may not affect the process of visual adaptation to rapid luminance flicker.

Short-Term Steady-State Pattern Electroretinography Changes Using a Multi-Pressure Dial in Ocular Hypertensive, Glaucoma Suspect, and Mild Open-Angle Glaucoma Patients: A Randomized, Controlled, Prospective, Pilot Study

Introduction

This study evaluates the effects of the multi-pressure dial (MPD) on steady-state pattern electroretinography (ss-pERG) parameters. The study is a randomized, controlled, prospective, pilot trial in a private practice setting with ocular hypertensive (OHT), glaucoma suspect, and open-angle glaucoma (OAG) subjects.

Methods

This study included nine patients (64 ± 9.0 years, nine female) with OHT, glaucoma suspect, or mild OAG. One eye of each subject was randomized to receive negative periocular pressure, while the contralateral eye served as the intrasubject control through the goggle without negative pressure. The Diopsys High Contrast Sensitivity ss-pERG protocol was conducted on both eyes of each subject while wearing the MPD device. Application of negative periocular pressure was set at 50% of baseline intraocular pressure for each study eye.

Results

Following 2 h of negative periocular pressure application, the difference in MagnitudeD (MagD) from baseline for eyes randomized to receive negative periocular pressure (+ 0.17 versus  − 0.26) was statistically significant (p = 0.023). Over the same period, the change in MagD/Magnitude (MagD/Mag ratio) from baseline for eyes randomized to receive negative periocular pressure was also higher (+ 0.14 versus  − 0.16), compared to the control eyes, approached significance (p = 0.059).

Conclusions

Following 2 h of MPD wear, the measured MagD and MagD/Mag ratio improved compared to control, suggesting that negative periocular pressure application to the anterior globe can lead to short-term improvement in one measure of retinal ganglion cell function.

Fixed-Luminance and Multi-Luminance Flicker Electroretinography Parameters in Patients with Early Active Birdshot Chorioretinopathy

Purpose To evaluate the parameters of the Fixed-Luminance and Multi-Luminance flicker electroretinography protocol among patients with early active birdshot chorioretinopathy.Methods Fixed-Luminance magnitude, Fixed-Luminance phase, Multi-Luminance magnitude area under the curve, and Multi-Luminance phase area under the curve parameters were compared between early active birdshot chorioretinopathy patients and an age-matched control group.Results There was no statistically significant difference between the Fixed-Luminance flicker magnitude (P = .6), the Fixed-Luminance flicker phase (P = .9), and the Multi-Luminance flicker phase area under the curve (P = .55) when each was compared to the normal population; however, the difference between the mean Multi-Luminance flicker magnitude area under the curve in our patients and the healthy control group was statistically significant. (P = .003)Conclusions Multi-Luminance flicker magnitude area under the curve has been shown to be significantly different from the normal population in the early active course of the disease.Abbreviations BSCR: birdshot chorioretinopathy; cd: Cadmium; ERG: Electroretinography; FA: Fluorescein angiography; FL-: Fixed-luminance; HVF: Humphrey visual field; Hz: Hertz; ICG: Indocyanine green; m²: Square meter; ML-: Multi-luminance; ms: millisecond; SITA: Swedish interactive thresholding algorithm; SWAP: Short wave-length automated perimetry.