AIM: To investigate for any detectable change in sub-foveal choroidal thickness following intravitreal injections of Ranibizumab or Aflibercept in patients with central involving diabetic macula edema(DME), evidenced by optical coherence tomography(OCT).

METHODS: Totally 17 patients with central involving DME who required and agreed to intravitreal anti-VEGF injection were invited to be the subject of this study. These injection-naive subjects were undergone three loading doses of monthly intravitreal anti-VEGF(Ranibizumab 0.5 mg/0.05 mL for 9 patients or Aflibercept 2 mg/0.05 mL for 8 patients)injection, and a clinic review appointment 1mo after the third injection. The changes of foveal choroidal thickness, visual acuity and central retinal thickness at 1mo were observed before and after treatment in 2 groups by enhanced depth image-optical coherence tomography(EDI-OCT).

RESULTS: We recorded a significant sub-foveal choroidal thinning and vision improvement after three loading doses of anti-VEGF(all P<0.05). The thinning effect between Ranibizumab and Aflibercept group was insignificant(all P>0.05). There was no significant correlation between pre-treatment sub-foveal choroidal thickness and vision improvement(r_s=-0.269, P=0.296). There was also no significant correlation between choroidal thickness changes with vision improvement, central retinal thickness change and age of subjects(all P >0.05).

CONCLUSION: Intravitreal Ranibizumab and Aflibercept injections both leads to significant sub-foveal choroidal thinning in DME subjects. It was accompanied with significant vision improvement with no evidence of immediate detrimental effect of choroidal thinning. Future research with a longer study duration would help in establishing the duration and long term effect of choroidal thinning.