Electroretinographic oscillatory potentials in diabetic retinopathy
ABSTRACT The oscillatory potentials of the electroretinogram in dark and light adaptation were evaluated by Fourier transform in 87 diabetics and 74 age-matched controls. The study consisted of four groups: normal control, no observable diabetic retinopathy, background diabetic retinopathy and proliferative diabetic retinopathy. A reduction in the amplitude of each oscillatory potential, the summed amplitudes, the area and the total power of the oscillatory potentials as well as delayed implicit time of each oscillatory potential peak in dark and light adaptation could be found in patients with background diabetic retinopathy and proliferative diabetic retinopathy. The amplitude of oscillatory potential 4 in dark adaptation and the total power of the oscillatory potentials in light adaptation seemed to be affected in patients with no observable diabetic retinopathy. The implicit time of oscillatory potential 2 in dark adaptation was valuable to distinguish between patients with no observable diabetic retinopathy and background diabetic retinopathy.
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ABSTRACT: Glaucoma is a leading cause of blindness. It is a multifactorial condition, the risk factors for which are increasingly well defined from large-scale epidemiological studies. One risk factor that remains controversial is the presence of diabetes. It has been proposed that diabetic eyes are at greater risk of injury from external stressors, such as elevated intraocular pressure. Alternatively, diabetes may cause ganglion cell loss, which becomes additive to a glaucomatous ganglion cell injury. Several clinical trials have considered whether a link exists between diabetes and glaucoma. In this review, we outline these studies and consider the causes for their lack of concordant findings. We also review the biochemical and cellular similarities between the two conditions. Moreover, we review the available literature that attempts to answer the question of whether the presence of diabetes increases the risk of developing glaucoma. At present, laboratory studies provide robust evidence for an association between diabetes and glaucoma.Clinical and Experimental Optometry 01/2011; 94(1):4-23. DOI:10.1111/j.1444-0938.2010.00546.x · 1.26 Impact Factor
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ABSTRACT: PURPOSE. Recording oscillatory potentials (OPs) to document how age impacts on rod- and cone-driven inner retina function. METHODS. Dark- and light-adapted electroretinogram (ERG) luminance-response functions were recorded in healthy human subjects aged 20-39, 40-59, and 60-82 years. Raw ERG traces (0.1-300Hz) were filtered (75-300Hz) to measure OPs trough-to-peak in the time-amplitude domain. Morlet wavelet transform (MWT) allowed documenting OPs time-amplitude-frequency distribution from raw traces. RESULTS. Under dark adaptation, both methods revealed reduced OP amplitudes and prolonged implicit times by 40 years of age. MWT identified a high-frequency band as the main oscillator, which frequency (150-155Hz) was unaffected by age. Under light adaptation, most OP peaks were delayed by 40 years of age. Peak-trough measures yielded inconsistent results in relation to luminance. Contrastingly, MWT distinguished two frequency bands at all luminances: high frequency (135 ± 6Hz) time locked to the onset of early OPs and low frequency (82 ± 7Hz), giving rise to early and late OPs. By 60 years, there was a consistent power reduction specific to the low-frequency band. CONCLUSION. Age-related OP changes precede those seen with a- (photoreceptoral) and b-waves (post-photoreceptoral). In addition, MWT allows quantifying distinct low- and high-frequency oscillators in the human retina, which complement traditional OP analysis methods. The identification of an age-independent OP marker (light-adapted high frequency band) opens a new dimension for the screening of retinal degenrations and their impact on inner retina function.Investigative Ophthalmology & Visual Science 07/2014; 55(8). DOI:10.1167/iovs.14-14219 · 3.66 Impact Factor
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ABSTRACT: In cross-sectional fashion, we recorded the maximal combined response and 30-Hz flicker responses in 178 adult diabetics and 40 normal controls according to the recommendations of the International Society of Clinical Electrophysiology of Vision. The oscillatory potentials were extracted from the maximal combined response by high-pass filtering. The clear media and attached retina were criteria for inclusion in this study. The data were statistically analyzed with the expectation that this procedure may provide a new feature that could have some clinical significance. Timing delays occurred more frequently than amplitude reductions in the maximal combined response and flicker responses, while amplitude reductions were more common in the first and second oscillatory potentials. The hypernormal b-wave amplitude was rare. The summed amplitude of the oscillatory potentials was highly correlated with the total power of the oscillatory potentials (the frequency domain). A reduction of the second oscillatory potential amplitude was more common than a reduction of the summed amplitude or total power. The electroretinographic component that demonstrates retinal dysfunction in the earlier stage may be a valuable indicator. In the early stage, a delay in the a-wave time and a reduction in the second oscillatory potential amplitude were the most frequent abnormalities: analysis of variance demonstrated that the summed amplitude of the oscillatory potentials and second oscillatory potential amplitude and time were the most sensitive measures of the diabetic retina. Hence, the second oscillatory potential amplitude may be the most sensitive and valuable indicator representing a quantitative measure of overall retinal dysfunction.Documenta Ophthalmologica 09/1997; 94(3):201-13. DOI:10.1007/BF02582979 · 1.11 Impact Factor