Study of OCT based biomarkers as a predictor of visual outcome in diabetic macular edema

Abstract

To determine the association between optical coherence tomography (SD-OCT) based biomarkers and visual acuity (VA) in diabetic macular edema (DME). This cross-sectional study was conducted at a tertiary care teaching hospitalbetweenJanuary 2021 and July 2022.The study included 54 eyes (30 patients) with DME. Based on the early treatment diabetic retinopathy study (ETDRS) grading system, these were classified as mild (n=1), moderate (n=31), severe (n=14), and very severe (n=8) non-proliferative diabetic retinopathy (NPDR). The demographics, VA recorded using ETDRS chart and ETDRS scoring system, slit lamp biomicroscopy findings, colour fundus pictures and biomarkers determined using macular scans on SD-OCT were noted. Six eyes with proliferative diabetic retinopathy (n-4) and considerable media opacity (n-2) were excluded. The data was entered into Microsoft Excel spreadsheet 2021and IBM's SPSS 26 statistical program was used to calculate the results.VA and biomarkers, which included central macular thickness, disorganisation of retinal inner layers (DRIL), ellipsoid zone disruption (EZD), choroidal thickness were measured on SD-OCT.: The mean age was 59.4±9.4 years, and male to female ratio was 1.3:1. Mean uncorrected and best corrected VA were 46 and 61 letters, 55.12±1.76 and 67.25±10.05 letters for moderate NPDR, 43.07±3.95 and 52.14±17.83 letters for severe NPDR, and 26.50±16.53 and 36±16.38 letters for very severe NPDR, respectively. VA deteriorated with increasing disease severity. Poorer VA was associated with increased average foveal and macular thickness and increased mean horizontal disruption of the inner retinal layers (DRIL). Average choroidal thickness positively correlated with increasing DR severity. : Poorer VA was associated with increasing DR severity, increased central retinal thickness, increased mean horizontal DRIL and increased average foveal choroidal thickness. We found no statistically significant correlation between VA and ellipsoid zone disruption.