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Y. Rotenstreich; Interocular Amplitude Differences of the Full Field Electroretinogram With Increment Light Intensities in Normal. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2890.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the interocular amplitude response difference of the electroretinogram (ERG) for normal subjects in different light intensities.
36 subjects, without retinal changes of clinical significance by ophthamoscope, and normal ERG responses were included. They included 20 men and 16 women, with a mean age of 40 (SD 16) years and range of 16-67 years. ERG was recorded in both eyes following the International Society for Clinical Electrophysiology of Vision (ISCEV) standard protocol. The interocular percentage differences of the ERG b-wave amplitudes were calculated and presented as percentiles (25th, 50th, 75th, 95th), means (SD), and medians.
Isolated rod, scotopic maximal in 0dB, +10dB, +20dB light intensities, dark adapted 30 Hz flicker, photopic single flash in 0dB, +5dB light intensities, and light adapted 30 Hz flicker responses were recorded. The median interocular percentage differences in the b-wave amplitudes for the above ERG stimulus responses were 8%, 8%, 7%, 7%, 10%, 10% and 7%, respectively. ANOVA identified smaller b-wave interocular percentage differences for the flicker than the single plash and larger photopic than scotopic (p=0.015) however, there was no effect of light intensities (p>0.05). The mean interocular percentage differences were 9%, 9%, 9%, 9%,%, 12%, 13% and 8%. The 95th percentiles for the interocular percentage differences were 22%, 19%, 19%, 24%, 28%, 29%, and 17%, respectively.
The interocular percentage differences in the ERG b-wave amplitudes for seven different stimulus responses showed significant difference in our cohort of individuals without clinically significant retinal changes. Flicker and scotopic single flash responses demonstrated lower interocular percentage differences with median of 7-8% and a 95th percentile of 17-24% than the photopic single flash responses with median of 10% and a 95th percentile of 28-29%. However, different light intensities demonstrated similar interocular percentage differences. Our findings should be useful for determining sample sizes in future therapeutic trials on retinal diseases with monocular therapeutic strategies and may also have application for the more accurate detection of asymmetric retinal disease.
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