Abstract
Purpose :
To identify the type and prevalence of retinal edema in the initial stages of retinopathy in diabetes type 2.
Methods :
In this retrospective cross-sectional study, SD-OCT layer by layer analysis of the retina in association with OCT-Leakage, a new algorithm to detect sites of low optical reflectivity (LOR) ratios, were used to examine eyes with minimal, mild and moderate diabetic retinopathy (DR). Increased retinal thickness (RT) with corresponding increased LOR ratios identifies extracellular edema whereas increased RT without corresponding increased LOR ratios identifies intracellular edema. The eyes were grouped by DR severity using the 7 field ETDRS protocol (levels 10-20, 35 and 43-47).
Results :
A total of 142 eyes from 142 patients (28% women) aged 52-88 years were imaged. Macular edema, either subclinical (SCME) or central involved (CIME), was present in 43% of eyes in group 10-20, 41% of eyes in group 35 and 38% in group 43-47. CIME was found in 7%, 7% and 12%, respectively for each group. In the eyes with increased retinal thickness, the INL, was the layer showing higher and most frequent increases in retinal thickness (79%). The edema was identified as predominantly intracellular in group 10-20 (65%) and extracellular in groups 35 (77%) and 43-47 (69%). Multivariate analysis showed correlation of retinal edema with metabolic control (p=0.007) but not with age, duration of disease or visual acuity.
Conclusions :
Eyes from diabetic patients in the initial stages of DR with different ETDRS retinopathy grading show similar prevalence of SCME and CIME, indicating that retinal edema can occur at any time since the initial stages of diabetic retinal disease, independently of the severity of the retinopathy. Diabetic retinal edema is located mainly in the INL and appears to be mostly extracellular except in the earliest stages of the disease where intracellular edema is present.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.