Purchase this article with an account.
J Jason McAnany, Jason C Park; Cone dysfunction in early-stage diabetic retinopathy assessed by electroretinography. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5948.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To quantify cone photoreceptor abnormalities in diabetics who have mild or no retinopathy by assessing the relationship between the activation phase of cone phototransduction and the flicker electroretinogram (ERG) in these individuals.
Light-adapted single flash and flicker ERGs were recorded from 20 subjects with diabetes mellitus (DM) who have no clinically-apparent retinopathy (NDR), 20 DM subjects who have mild nonproliferative diabetic retinopathy (NPDR), and 20 non-diabetic, age-equivalent controls. Values of Rmp3 (maximum amplitude of the massed photoreceptor response) and S (phototransduction sensitivity) were derived from a delayed Gaussian model that was fit to the leading edge of the single flash a-waves. Fundamental amplitude and phase of the flicker ERG were recorded across a broad range of temporal frequencies (6 to 100 Hz).
Analysis of variance (ANVOA) indicated significant differences among the groups (control, NDR, mild NPDR) in log S (F = 9.49, p < 0.001), whereas log Rmp3 did not differ significantly among the groups (F = 2.85, p = 0.07). ANOVA also indicated flicker ERG amplitude differences among the groups (F = 4.56, p = 0.02). Holm-Sidak pairwise comparisons indicated reduced amplitude for the mild NPDR group for frequencies of 45.5 Hz and greater (all t > 2.30, p < 0.05) and reduced amplitude for the NDR group for frequencies of 55.6 Hz and greater (all t > 2.09, p < 0.04). Flicker ERG timing (phase) did not differ significantly among the groups (F = 1.34, p = 0.27). 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).
Log S abnormalities were commonly observed in the DM subjects (50% of the sample), whereas Rmp3 abnormalities were relatively uncommon (13% of the sample). Flicker ERG amplitude abnormalities became increasingly apparent with increasing temporal frequency: 12.5% of the DM subjects had 31.25 Hz flicker ERG reductions, whereas 55% had reductions at 100 Hz. Reduced cone sensitivity and attenuated high frequency flicker ERGs provide evidence for impaired cone function in early-stage DR.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
This PDF is available to Subscribers Only