Efficacy and Safety of Intravitreal Dexamethasone Implants for Treatment of Refractory Diabetic Macular Edema

Purpose: To evaluate the safety and efficacy of intravitreal dexamethasone (IVD) implants in eyes with diabetic macular edema that did not respond to previous treatment. Methods: We included 46 eyes of 46 patients in this retrospective study. Each month, we recorded patient visual acuity with logarithm of the minimum angle of resolution using the Early Treatment Diabetic Retinopathy Study chart, central macular thickness measurements with optical coherence tomography, intraocular pressure(IOP), and posttreatment complication occurrence. Results: The mean follow-up time was 8.95 ± 1.33 months (range, 6 to 12). Best-corrected visual acuity improved significantly in the first 4 months after IVD, but no statistically significant change was observed over the following 2 months. Although a statistically significant decrease in central macular thickness was observed in the first 3 months, the change was not statistically significant in the following 3 months. There was a statistically significant increase in IOP in the first 2 months, but no statistically significant change was observed in the following months. IOP was controlled with medication in all patients with elevated IOP. Of the 26 phakic patients, two had cataracts requiring surgery. Conclusions: Cases of refractory diabetic macular edema that did not respond to previous treatment, such as anti-vascular endothelial growth factor injections and laser photocoagulation, exhibited improvements in visual acuity and decreases in retinal thickness after IVD implantation. Both functional and anatomical effects were observed in the first 3 months after injection. Repeat injections and frequent examination might be required for continued improvement. Side effects, such as cataracts and elevation of IOP, may require medical or surgical treatment.