Application of intravitreal dexamethasone implant in diabetic macular edema resistant to treatment of intravitreal ranibizumab

Purpose: To evaluate the efficiency and possible complications of intravitreal dexamethasone implant (IVD) in diabetic macular edema (DME) resistant to treatment of three consecutive intravitreal ranibizumab (IVR) injections. Materials & Methods: Fifty eyes of 38 patients were considered in this study. The best corrected visual acuity (BCVA), central macular thickness (CMT), values of intraocular pressure (IOP) are examined preoperatively and postoperatively in 1st, 2nd, 4th and 6th months of IVD implantation. Results: Twenty of the patients were women and 18 of the patients were men. Mean age was 64.63±7.15 (52–83) years. Mean number of IVR injection before IVD implantation was 3.4. Mean BCVA (LogMAR) was 0.874±0.398 before IVD implantation, 0.598±0.306 at 1st month, 0.602±0.340 at 2nd month, 0.708±0.359 at 4th month and 0.800±0.370 at 6th month. Mean of CMT was 519.700±155.802 µ before IVD implantation, 274.000±73.112 µ at 1st month, 307.98±87.869 µ at 2nd month, 387.82±110.503 µ at 4th month and 478.54±163.743 µ at 6th month. Improvements in BCVA and CMT were statistically significant (p<0.05) at 1st, 2nd and 4th months; however these values were not statistically significant at 6 months. At 1st day, 1st and 2nd months, the values of IOP were increased significantly after IVD. These values were observed to decrease to baseline after 3 months of implantation. During the follow-up period, it was recorded that IOP of 5 patients were higher than 21 mmHg. IOP of these patients were well controlled with topical medication. Cataract progression was observed in just 1 of the 22 phakic patients. Conclusion: In DME resistant to treatment of consecutive IVR, IVD implantation has been observed to be effective in increasing BCVA and decreasing CMT in first 3 months. IVD implantation can be considered as an alternative method in treatment of resistant DME. Key words: Diabetes, intravitreal dexamethasone, intravitreal ranibizumab, macular edema