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R.P. Danis, The Diabetic Retinopathy Clinical Research Network; Diurnal Variation in Retinal Thickening Measured by OCT . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5695.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate diurnal variation in Optical Coherence Tomography (OCT) measured retinal thickness in patients with center–involved diabetic macular edema (DME).
Ninety–one subjects with DME (median age 59 years, 46% female, 81% with type 2 diabetes and median diabetes duration 16 years) were recruited at 23 centers participating in the Diabetic Retinopathy Clinical Research Network (DRCR.net). In 145 eyes, all having OCT center point (CP) retinal thickness ≥ 200 microns at 8AM, CP thickness and visual acuity (VA) were measured at 8AM, 12PM, and 4PM, with additional OCT measurements at 9AM, 10AM, and 2PM. OCT3 retinal thickness maps were assessed by a reading center and manual re–measurements of CP thickness performed if necessary. To be considered clinically relevant, a relative change in calculated CP thickening (measured thickness minus mean normal thickness) between 8AM and 4PM had to be ≥ 25% and the absolute change in thickness had to be ≥ 50 microns (determined from preliminary analysis of reproducibility calculating the 95% half–width confidence interval for detection of change).
At 8AM, the median CP thickness was 328 microns and the median VA was 68 letters (approximately 20/50). Between 8AM and 4PM, 9 eyes of 7 subjects (6% of eyes, 95% CI, 3% to 12%) had a clinically relevant decrease in CP thickening; 3 eyes of 3 subjects (2%, 95% CI, 1% to 6%) had a clinically relevant increase in CP thickening. VA improved by >10 letters in 16 eyes and worsened by >10 letters in 8 eyes. Of the 9 eyes with a clinically relevant decrease in CP thickening, VA improved ≥ 10 letters in 1, and worsened ≥ 10 letters in 1.
Between 8AM and 4PM, we did not identify consistent clinically relevant change in retinal thickening or VA in the majority of eyes with DME, although they may systematically vary in a subset of these eyes. Our data do not provide information as to whether such eyes exhibit consistent daily diurnal variation. Supported by NEI grants U10 EY14231, 5 U10 EY14269–03, 5 U10 EY14229.
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