J Jason McAnany1,2, Jason C Park1. 1. Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States. 2. Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, United States.
Abstract
Purpose: To define the nature and extent of cone photoreceptor abnormalities in diabetic individuals who have mild or no retinopathy by assessing the activation phase of cone phototransduction and the flicker ERG in these individuals. Methods: Light-adapted single-flash and flicker ERGs were recorded from 20 diabetic individuals who have no clinically apparent retinopathy (NDR), 20 diabetic individuals who have mild nonproliferative diabetic retinopathy (NPDR), and 20 nondiabetic, age-equivalent controls. A-waves elicited by flashes of different retinal illuminance were fit with a delayed Gaussian model to derive Rmp3 (maximum amplitude of the massed photoreceptor response) and S (phototransduction sensitivity). Fundamental amplitude and phase of ERGs elicited by full-field sinusoidal flicker were obtained across a frequency range of 6 to 100 Hz. Results: ANVOA indicated that both diabetic groups had significant S losses compared with the controls, whereas mean Rmp3 did not differ significantly among the groups. ANOVA also indicated significantly reduced flicker ERG amplitude for frequencies ≥56 Hz for both diabetic groups compared with the controls. Flicker ERG timing (phase) did not differ significantly among the groups. Log Rmp3 + log S was significantly correlated with the patients' high-frequency (62.5 Hz) flicker ERG amplitude loss (r = 0.69, P < 0.001). Conclusions: The delayed Gaussian a-wave model is useful for characterizing abnormalities in the activation phase of cone phototransduction and can help explain flicker ERG abnormalities in early-stage diabetic retinopathy. Reduced cone sensitivity and attenuated high-frequency flicker ERGs provide evidence for impaired cone function in these individuals.
Purpose: To define the nature and extent of cone photoreceptor abnormalities in diabetic individuals who have mild or no retinopathy by assessing the activation phase of cone phototransduction and the flicker ERG in these individuals. Methods: Light-adapted single-flash and flicker ERGs were recorded from 20 diabetic individuals who have no clinically apparent retinopathy (NDR), 20 diabetic individuals who have mild nonproliferative diabetic retinopathy (NPDR), and 20 nondiabetic, age-equivalent controls. A-waves elicited by flashes of different retinal illuminance were fit with a delayed Gaussian model to derive Rmp3 (maximum amplitude of the massed photoreceptor response) and S (phototransduction sensitivity). Fundamental amplitude and phase of ERGs elicited by full-field sinusoidal flicker were obtained across a frequency range of 6 to 100 Hz. Results: ANVOA indicated that both diabetic groups had significant S losses compared with the controls, whereas mean Rmp3 did not differ significantly among the groups. ANOVA also indicated significantly reduced flicker ERG amplitude for frequencies ≥56 Hz for both diabetic groups compared with the controls. Flicker ERG timing (phase) did not differ significantly among the groups. Log Rmp3 + log S was significantly correlated with the patients' high-frequency (62.5 Hz) flicker ERG amplitude loss (r = 0.69, P < 0.001). Conclusions: The delayed Gaussian a-wave model is useful for characterizing abnormalities in the activation phase of cone phototransduction and can help explain flicker ERG abnormalities in early-stage diabetic retinopathy. Reduced cone sensitivity and attenuated high-frequency flicker ERGs provide evidence for impaired cone function in these individuals.
Authors: Elliott H Sohn; Hille W van Dijk; Chunhua Jiao; Pauline H B Kok; Woojin Jeong; Nazli Demirkaya; Allison Garmager; Ferdinand Wit; Murat Kucukevcilioglu; Mirjam E J van Velthoven; J Hans DeVries; Robert F Mullins; Markus H Kuehn; Reinier Otto Schlingemann; Milan Sonka; Frank D Verbraak; Michael David Abràmoff Journal: Proc Natl Acad Sci U S A Date: 2016-04-25 Impact factor: 11.205
Authors: Hille W van Dijk; Pauline H B Kok; Mona Garvin; Milan Sonka; J Hans Devries; Robert P J Michels; Mirjam E J van Velthoven; Reinier O Schlingemann; Frank D Verbraak; Michael D Abràmoff Journal: Invest Ophthalmol Vis Sci Date: 2009-01-17 Impact factor: 4.799
Authors: J Jason McAnany; Jason C Park; Karen Liu; Michelle Liu; Yi-Fan Chen; Felix Y Chau; Jennifer I Lim Journal: Acta Ophthalmol Date: 2019-09-13 Impact factor: 3.761