Subfoveal choroidal thickness in diabetic macular edema

Purpose: To evaluate subfoveal choroidal thickness (SFCT) in eyes with diabetic macular edema (DME) using spectral domain OCT (SD-OCT). Materials and methods: Ninety eyes were divided into three equal groups: group A, non-proliferative diabetic retinopathy (NPDR) with no DME; group B, NPDR having DME; and group C, non-diabetic patients. The central subfield retinal thickness (CSRT) and SFCT were measured using spectral domain OCT. Results: There was a moderate negative correlation between age and SFCT in group B (r=-0.455, P=0.012). We found no significant correlation between best corrected visual acuity (BCVA) and SFCT in all groups (for groups A, B, and C, respectively: r=0.189, P=0.316; r=-0.195, P=0.302; and r=-0.181, P=0.337). There was no significant correlation between duration of diabetes and SFCT (r=-0.118, P=0.534 and r=-0.136, P=0.475 for groups A and B, respectively). The CSRT was 229.13±16.2, 336.4±74.85, and 223.13±16.9 µm in groups A, B, and C, respectively. The mean SFCT was 260.6±49.2, 259±50.8, and 252±50 µm in groups A, B, and C, respectively. We found no significant correlation between CSRT and SFCT in all groups (for groups A, B, and C, respectively: r=-0.049, P=0.796, r=0.239, P=0.204, r=-0.021, P=0.914). There was no significant difference in SFCT between group B (DME) on one hand and groups A and C on the other hand (P=0.9 and 0.59, respectively). Conclusion: There is no significant correlation between CSRT and SFCT in DME. Choroidal thickness assessment is not an indicator of the severity of DME and cannot be used as a monitor of its progression.