Transient reduction in macular deep capillary density on optical coherence tomography angiography after phacoemulsification surgery in diabetic patients

BACKGROUND: To evaluate macular microvascular changes and associated factors in diabetic patients following uncomplicated phacoemulsification surgery. METHODS: In this prospective observational study, we enrolled diabetic patients and non-diabetic controls who underwent phacoemulsification surgery. Participants were examined at postoperative day 1 (POD1), 10 (POD10), 30 (POD30), and 90 (POD90), using macular 3x3mm OCT angiography scan (RTVue-XR Avanti; Optovue, Inc., Fremont, CA). Integrated automated algorithms were used to quantify parafoveal vessel density (VD) in superficial capillary plexus (SCP) and deep capillary plexus (DCP). To minimize measurement bias, subjects with corneal edema or capsular opacity at any postoperative visit were excluded. RESULTS: The study included 21 eyes of 21 diabetic patients and 21 eyes of 21 non-diabetic controls. In diabetic patients, no significant change in SCP-VD could be detected (P = 0.57); DCP-VD reduced from 50.24 ± 2.33% at POD1 to 48.33 ± 3.07% at POD30 (P = 0.019), and restored to 50.74 ± 3.44% at POD90 (P = 1.00). The DCP-VD change at POD30 in diabetic patients (− 1.90 ± 2.61%) was significantly different from that in controls (1.31 ± 2.61%) (P < 0.001). The amount of DCP-VD reduction was correlated with foveal and parafoveal thickening (r = 0.431, P = 0.051 and r = 0.514, P = 0.017, respectively), high cumulative dissipated energy (P = 0.032) and increased hemoglobin A1c concentration (P = 0.037). CONCLUSIONS: Phacoemulsification in diabetic patients caused transient reduction in DCP-VD, which was associated with poor glycemic control, surgical trauma, and postoperative macular thickening. Our results added a new dimension to our understanding of the complex biologic effects of cataract surgery in diabetic subjects.