Choroidal Blood Flow After Intravitreal Ranibizumab in Vitrectomized and Non-Vitrectomized Eyes with Diabetic Macular Edema.

Aim: Diabetic retinopathy staging system and progression predictors are soon to be considered insufficient for ophthalmologic practice. Given the growing evidence of the role of choroidal dysfunction, our purpose was to assess choroidal vascular changes with intravitreal ranibizumab (RBZ) treatment in diabetic macular edema (DME).

Methods: This was a prospective longitudinal cohort study. The study included DME eyes, grouped in vitrectomized (group 1) and non-vitrectomized (group 2) eyes, submitted to RBZ in a pro re nata regimen, with 24 weeks of follow-up. Main outcome measures such as central subfield foveal thickness (CFT), choroidal thickness (CT), and choroidal vascular index (CVI) were obtained from structural OCT, and choriocapillaris flow density (CCD) was obtained from OCT angiography and analyzed before and after treatment.

Results: Thirty-one patients were included, 10 eyes in group 1 and 24 eyes in group 2. The mean number of injections was 5.18 (range 2-6). Globally, there was an improvement in BCVA (+4.3 ETDRS letters, p=0.004) and CFT (-84.6 µm, p<0.001) with no changes in CT, CVI, or CCD (p>0.05). When considering only group 2, there was a significant decrease in CT (p=0.033) and a significant increase in CCD (p=0.010) 6 months after treatment, with no differences in CVI (p=0.111). Baseline CVI was correlated with visual acuity at week 24 both globally (=0.406, p=0.029) and in group 2 (=0.604, p=0.004).

Conclusion: In non-vitrectomized eyes, choriocapillaris blood flow improves with RBZ. Baseline CVI may correlate with visual function after RBZ. ClinicalTrials.gov NCT04387604.