Correlation Between Diabetic Macular Edema and Subfoveal Choroidal Thickness by Optical Coherence Tomography

Background: The choroidal thickness (CT) in patients with diabetic macular edema (DME) exhibited different patterns, including thickening, thinning, or no changes. Research indicated that the average thickness of the choroid layer beneath the fovea, known as subfoveal choroidal thickness (SFCT), was dramatically decreased in these individuals. However, other studies found that SFCT was greater in thickness..Aim: The aim of the study was to assess subfoveal choroidal thickness in patients with diabetic macular edema (DME).Patients and methods: This cross-sectional observational controlled study included 60 human eyes divided into three groups, Group I which included 20 diabetic eyes with central macular thickness (CMT) > 400 µm, Group II which included 20 diabetic eyes with CMT < 400 µm, and Group III (Control) which included 20 normal eyes. All participants were subjected to optical coherence tomography (OCT) imaging by swept source Topcon 3D OCT 2000. OCT exam includes measurement of CMT and SFCTResults: In group I, the mean CMT was 469.25 ± 63.795 µm, and SFCT mean value was 258.35±63.14 µm. In group II, the mean CMT was 317.25±35.437 µm, and SFCT was 275.05±90.213 µm. In control group, CMT mean value was 237.56±9 µm, and SFCT mean value was 214.33±71.97 µm. There is a statistically significant difference between group I, group II and control group as regard CMT (P =0.001). However, the difference between the three groups was insignificant statistically in terms of SFTC (P = 0.34). The difference between each two groups of our study regarding SFCT was insignificant statistically (P= 0.2, 0.08, and 0.5 respectively).Conclusion: There is insignificant relation between CMT and SFCT in patients with DME. Choroidal thickness evaluation does not indicate the severity of DME and cannot be used to track its progression