Glycemic control and macular edema in patients undergoing cataract surgery

Aims: Cataract, the most common cause of blindness, has higher prevalence among patients with diabetes mellitus. About 20% of cataract surgeries are performed on patients with diabetes. One of the complications of cataract surgery is pseudophakic cystoid macular edema (CME). This study examined whether patients’ glycemic control (as indicated by HbA1c level before cataract surgery) is associated with CME incidence within one year post-surgery. Methods: We conducted a retrospective cohort study of 1285 diabetes patients over age 18 who underwent cataract surgery between January 2015 and January 2020. Data were obtained from medical records reporting glycated hemoglobin (HbA1c) level prior to surgery and post-operative CME with intraocular anti-vascular endothelial growth factor injections. Results: The patients with CME complications were younger, with longer duration diabetes, and higher percentages of type 1 diabetes and diabetic retinopathy. The main variables influencing risk of post-operative CME were found to be diabetic retinopathy and HbA1c level. Multivariate analysis revealed that HbA1c is an independent risk for post-operative CME with a relative risk of 2.01 when HBa1c is above 7 c (95% CI, 1.10–3.67). Conclusion: The study demonstrates that pre-cataract surgery diabetes control, measured by HbA1c level, is an independent risk factor for developing post-surgery CME.