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Olga Kraszewska, Quentin Davis, Bonnie Stintsman, Robert Feig, Robert Levy, Colette Manning; Flash electroretinogram (fERG) in Age-related Macular Degeneration (AMD). Invest. Ophthalmol. Vis. Sci. 2018;59(9):2416.
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Age-related Macular Degeneration (AMD) is a leading cause of vision loss in the 50+ population. Visual electrodiagnostic testing provides valuable objective assessment of the retinal function. Pattern ERGs and VEPs are typically recorded to assess baseline and determine the prognosis. Flash electroretinogram is often recorded from those patients to rule out other ailments and it would be practical and convenient to evaluate macular function at the same time. In this study we examine flash ERG results obtained from AMD patients enrolled in the RETeval All Comers Trial (REACT).
REACT is a multicenter, cross-sectional study to collect exemplary electroretinograms (ERGs) with the RETeval device (LKC Technologies, Inc. Gaithersburg MD USA). All patients at the trial sites who visited the clinic for an eye appointment were invited to participate. Eleven patients (7 female) with AMD have been tested, aged between 58 and 94. The AMD severity was dry advanced (n=2), dry intermediate (n=1), dry early (n=4), dry but not staged (n=2), and wet (n=2). Sensor strip electrodes and RETeval device have been used to record the ERGs. Patients were dilated and the following photopic responses were evaluated: LA 3.0 flash and flicker, on/off response, and photopic negative response (PhNR). Amplitudes and implicit times were measured and compared to the age-adjusted 95% reference intervals obtained using the visually normal subjects in this trial.
The on-off response was abnormal in 9 subjects (82%). Of the two subjects the on-off response was normal, one had early dry AMD (with 20/25 acuity in the tested eye) and the other had wet AMD (with 20/50 acuity in the tested eye). The LA 3.0 flicker was abnormal in 3 subjects (27%), while the LA 3.0 flash was abnormal in 5 subjects (45%). The PhNR a-wave and b-wave was abnormal is 6 subjects (55%), while the later ganglion cell response of the PhNR was abnormal is only 3 subjects (27%).
The full-field flash ERG is a response from the whole retina, and thus would not be expected to be affected by a macula-only disease. Nevertheless, all ERG measures were abnormal significantly more often than the 5% expected rate when using 95% reference intervals. The on-off test appears to be particularly sensitive to AMD, with a sensitivity of 82% and a specificity of 95%. These initial results indicate an ERG utilizing an on-off stimulus may be useful in the detection of AMD.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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