Choroidal thickness and vascularity in diabetic macular edema: impact of serous macular detachment.

PURPOSE

This comparative study aimed to investigate the role of the choroidal vascular system in the formation of serous macular detachment (SMD) in diabetic macular edema (DME).

METHODS

A study population of 126 naive patients was divided into two groups: group 1 (DME without serous macular detachment, n = 90) and group 2 (DME with serous macular detachment, n = 36). The following assessments were conducted: best corrected visual acuity (BCVA), central macular thickness (CMT), the height of the SMD, subfoveal central choroidal thickness (SFCT), choroidal thickness at the nasal (SFNCT) and temporal (SFTCT) borders of the subfoveal 1500-micron area, choroidal thickness at the nasal (SMNCT) and temporal (SMTCT) borders of the submacular 6000-micron area, and subfoveal and submacular choroidal vascularity index (CVI).

RESULTS

BCVA was significantly better in group 1, whereas CMT was greater in group 2 (p = 0.002, p < 0.001, respectively). The logMAR BCVA was positively correlated with CMT in both groups (p < 0.001 for both, r = 0.940, and r = 0.920, respectively), but BCVA was not significantly correlated with SFCT, CVI or submacular CVI. Group 2 also showed significantly greater values for SFCT, SFNCT and SFTCT (p < 0.001) and SMNCT (p = 0.046); whereas SMTCT values showed no significant difference (p = 0.074). With regard to the subfoveal and submacular CVI, no significant differences were found between the groups (p = 0.142, p = 0.468).

CONCLUSION

While the presence of SMD in DME affects choroidal thickness, no significant difference was observed in the choroidal vascularity index. These findings may enlighten SMD pathogenesis, supporting the hypothesis that choroidal changes are not directly linked to alterations in vascular structure.