Background: Diabetic Macular Edema is a critical complication of diabetic eye disease, the effect of Anti-VEGF injection in diabetic eyes does not stop at the retina alone as it also influences the choroidal circulation.
 
Aim of the study: To compare subfoveal choroidal thickness (SFCT) before and after intravitreal injection of ranibizumab in DME with the use of Cirrus HD-OCT by enhanced depth spectral-domain imaging (EDI-OCT).
 
Patient and methods: A prospective study that was demonstrated on 50 eyes of 35 cases with DME. Fundus fluorescein angiography was done for all patients. All patients were received three intravitreal injection of (0.5 mg/0.05 ml ranibizumab) with one-month interval. EDI-OCT was done preoperative and one-month following the third injection.
 
Results: The mean CT (Choroidal Thickness) was 257.62 ±49.207 µm with a range from 154 µm to 361 m preoperatively. While the mean CT was 239.78 ± 47.225 µm with a range from 150 µm to 346 µm postoperatively, There were obvious changes between the preoperative and the postoperative SFCT measured by EDI-OCT and there was a positive significant correlation among the baseline SFCT and the change of SFCT (p. value 0.036).
 
Conclusion: Intravitreal injection of 0.5 mg/0.05 ml ranibizumab in the treatment of DME resulting in significant reduction of SFCT with greater response in cases with higher baseline SFCT, but improvement of BCVA was related to retinal thickness not to CT which needs further evaluation.