Optical coherence tomography patterns of diabetic macular edema in a Saudi population

Purpose: The study aims to describe the patterns of diabetic macular edema (DME) and their association with visual acuity using optical coherence tomography (OCT). Patients and methods: This is a retrospective observational study with chart review of patients with DME including both type 1 and 2 diabetics seen between January 2015 and January 2016. Main Outcome Measures: Type of diabetes, diabetes duration, best-corrected visual acuity, DME pattern, central macular thickness (CMT), and stage of diabetic retinopathy. DME was classified based on OCT scans into: sponge-like diffuse retinal thickness (SLDRT), cystoids macular edema (CME), and sub-retinal fluid (SRF). Results: 227 eyes (144 patients) were included. The SLDRT represented 67.84%, CME 19.82%, and presence of SRF 2.20%. OCT scan from 21 patients (22 eyes) displayed more than a single pattern. The CMT and visual acuities varied depending on the DME morphologic patterns. SLDRT was associated with the least affected mean visual acuity of 0.2±0.21. SRF signified the worst mean visual acuities. Increase in CMT significantly correlated with reduced visual acuity (P=0.005). A statistically significant positive correlations between diabetic stage—high risk proliferative diabetic retinopathy (PDR) and severe non-proliferative diabetic retinopathy (NPDR)—with the CMT (P=0.050) and (P=0.021) respectively, were observed. A significant positive correlation between the duration of diabetes, age and type 1 diabetes with visual acuity in LogMAR (P=0.003), (P=0.03), and (P=0.0005) respectively. Conclusions: SLDRT was the most common morphological subtype of DME patterns and increasing retinal thickness impaired the visual acuity. Older ages, longer diabetic duration and type 1 diabetes are considered significant risk factors for visual acuity impairment. The study also suggests that there is a significant correlation between the DME patterns and visual acuity.