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Irfan Nizarali Kherani, Shveta Bali, Ange-Lynca Kantungane, Asma Hermas, Garfield Miller, Stuart G Coupland; Applying the Pattern Electroretinogram (PERG), Uniform Field Electroretinogram (ERG) and Photopic Negative Response (PhNR) in Clinical Glaucoma Practice. Invest. Ophthalmol. Vis. Sci. 2019;60(9):2444.
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© ARVO (1962-2015); The Authors (2016-present)
Visual electrodiagnostics objectively record the electrical activity of the visual system in response to stimuli. Glaucoma is traditionally followed with optical coherence tomography (OCT) assessment of the thickness of the retinal nerve fiber layer (RNFL) and Humphrey visual field (HVF) automated perimetry. Study has shown that eletrodiagnostics may indicate glaucoma progression even earlier than the present-day standard of care. The primary purpose of this study is to compare the Diagnosys Espion E3 and Envoy pattern electroretinogram (PERG), uniform field eletroretinogram (UFERG) including photopic negative (PhNR) response results as well as the OCT-RNFL and HVF results in normal, glaucoma suspect and glaucoma patients.
Patients with suspect, early or moderate glaucoma assessed at clinics at the University of Ottawa Eye Institute and Riverside Eye Care Centre were recruited. All patients completed OCT-RNFL and HVF as part of their follow-up. They subsequently underwent PERG and UFERG including the PhNR assessments.
A total of 102 eyes have been recruited to the study. While the visual field and OCT RNFL showed statistically significant differences between glaucoma suspect and glaucoma patients, the IOP and visual acuity did not. The PERG bars N95 amplitude and latency were significantly decreased in both glaucoma suspects and glaucoma patients relative to normal. The PERG checks N95 amplitude and latency were also significantly decreased in both glaucoma suspects and glaucoma patients relative to normal. The PhNR amplitude and latency were both significantly decreased in glaucoma suspects and glaucoma patients relative to normal patients. There were no statistically significant differences in the UFERG a or b waves, in either amplitude or latency.
Glaucoma appears to be associated with a statistically significant reduction in the PERG bars and checks N95 amplitude and latency as well as the PhNR amplitude and latency in both glaucoma suspect and glaucoma patients relative to normal. This early identification of changes secondary to glaucoma could permit earlier diagnosis and management for what is a progressive irreversible disease.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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