Changes in chorioretinal flow index after cataract surgery: an optical coherence tomography angiography study.

ABSTRACT

PURPOSE: Pseudophakic cystoid macular edema (CME) occurs in up to 2% of uneventful cataract surgeries. This study evaluates changes in macular blood flow succeeding uneventful phacoemulsification cataract extraction among otherwise visually healthy subjects. METHODS: This prospective study included 18 eyes of 18 patients undergoing routine phacoemulsification. Optical coherence tomography angiography (OCT-A) was performed using the Angio-Retina 6 × 6 mm protocol with the XR Avanti Angio-Vue system (Optovue Inc., Fremont, California) prior to the surgery and 4-8 weeks thereafter. Exclusion criteria included motion artifacts, segmentation errors and signal strength index (SSI) < 40. The main outcome measure was change in flow index (FI) measured in all 4 retinal segmentation layers within an area of 1 mm diameter around the foveal center. RESULTS: Following surgery, a significant increase in SSI (46.65 ± 8.62 versus 53.12 ± 8.07, p = 0.01), superficial plexus FI (0.98 ± 0.23 versus 1.16 ± 0.16, p = 0.02) and deep plexus FI (0.54 ± 0.46 versus 0.93 ± 0.39, p = 0.01) was found. No significant changes were noted in the outer retina or the choriocapillaris. CONCLUSION: The study demonstrates a significant increase in FI in the superficial and deep retinal plexus following uneventful cataract surgery, with the greatest changes occurring in the latter. These findings corroborate evidence from structural imaging and support the vascular etiology of pseudophakic CME.