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Torcato Santos, Inês Marques, Maria Helena Madeira, Ana Rita Santos, Conceicão F Lobo, Jose G Cunha-Vaz; Characterization of macular edema in the initial stages of diabetic retinopathy: a 3-year longitudinal study. Invest. Ophthalmol. Vis. Sci. 2021;62(8):2531.
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To characterize the prevalence and progression of macular edema in minimal to moderate non-proliferative diabetic retinopathy (DR) using measurements of tissue optical reflectivity (OCT-Leakage).
Seventy-four eyes from 74 diabetic DR type 2 patients were imaged annually during a 3-year follow up with the CIRRUS™ HD-OCT 5000 with AngioPlex (Zeiss, Dublin, CA) using the “Angiography 6mmx6mm” protocol. Forty healthy eyes from 40 control volunteers were also imaged on a single visit.OCT-A structural data was segmented using an in-house segmentation algorithm. OCT-Leakage, an algorithm to detect sites of low optical reflectivity (LOR) was applied to the full retina and to each retinal layer. Extracellular fluid was measured by the LOR area ratio, which stands for the fraction of the number of A-scans with LOR and the total number of A-scans, within the considered area. DRCR.net standards were used to identify eyes with subclinical (SCME) and clinical macular edema (central involved macular edema - CIME).
The 74 eyes from 74 patients were classified using the ETDRS severity scale, Grade 10 to 20 (n=23), 35 (n=31) and 43 to 47 (n=20).CIME was found in the first visit in 8.7% of eyes in ETDRS group 10-20, 9.7% of eyes in ETDRS group 35 and 15.0% of eyes in ETDRS group 43-47. In the eyes with increased central retinal thickness (CRT), the inner nuclear layer (INL) is the layer showing most frequent increase in thickness (52.9%). In the eyes with CIME at baseline, there is a strong correlation between the INL OCT-Leakage LOR (LOR-INL) and CRT value differences from V01 to V04 (Spearman rho=0.73, p-value=0.03). The changes in CRT and LOR-INL occur in parallel and are characterized by frequent fluctuations. The variations observed in the LOR-INL showed a much wider range well demonstrated by the standard deviation of the measurements of the average value (The Table).
Eyes from diabetic patients in the initial stages of DR with different ETDRS retinopathy grading shows similar prevalence of macular edema, showing that it increases only moderately with severity of the retinopathy. OCT-Leakage measurements of INL correlate with the presence of CIME and its evolution over a series of 4 visits during a 3-year period of follow up, showing that its course is characterized by frequent fluctuations.
This is a 2021 ARVO Annual Meeting abstract.
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