Combined Intravitreal Dexamethasone Implant and Cataract Surgery in Patients with Diabetic Retinopathy: Effect on Retinal Morphology and Function

Introduction: Cataract surgery can be associated with vision-threatening complications in patients with diabetes. This study aimed to assess the functional and anatomic outcomes of the intravitreal dexamethasone (DEX) implant, administered at the time as cataract surgery, in patients with diabetic retinopathy and diabetic macular edema (DME). Methods: This was a retrospective, observational, and single-center study. The primary endpoint was the mean change in central macular thickness (CMT) from baseline to month 1. Secondary endpoints included mean change in best corrected visual acuity (BCVA) from baseline to month 1 and 3, mean change in CMT from baseline to month 3, the photopic negative response (PhNR) and the b wave of flash full-field electroretinogram from baseline to month 1, and the incidence of adverse events. Results: Twenty-four eyes of 21 patients were included in the study. The mean (range) age of patients was 69 (63–87) years and 13 (61.9%) were men. Mean (standard deviation) CMT significantly decreased from 447 (134) lm at baseline to 341 (134) lm at month 1 (mean difference - 106 ± 134 lm, 95% CI - 183.9 to - 28.1 lm; p = 0.0087). BCVA significantly improved from 46 (20) ETDRS letters at baseline to 59 (22) ETDRS letters at month 1 (mean difference 13 ± 21 letters, 95% CI 0.8–25.2 letters; p = 0.0375). Regarding electrophysiology, there was a statistically significant reduction in mean PhNR from 5.24 (1.67) lV at baseline to 3.73 (1.19) lV at month 1 (mean difference - 1.51 ± 0.42 lV, 95% CI - 2.4 to - 0.7 lV, p = 0.0008); whereas b wave amplitude did not change (12.69 ± 6.89 lV at baseline versus 12.29 ± 6.30 lV at month 1; p = 0.8347). Four (16.7%) eyes developed ocular hypertension over the course of follow-up, which was successfully controlled with topical hypotensive medication. Conclusion: Perioperative DEX implant significantly improved both anatomic and functional outcomes in patients with DME who underwent cataract surgery.