The outcome of fluocinolone acetonide intravitreal implant is predicted by the response to dexamethasone implant in diabetic macular edema

Background/Objectives To investigate if the visual and anatomic response to the first dexamethasone implant (DEX) predicts the 12-month clinical outcome after shifting to fluocinolone acetonide (FAc) implant in patients with diabetic macular oedema (DMO). Methods Retrospective cohort study including pseudophakic patients with previously treated DMO, undergone one or more DEX injections before FAc. Functional and morphologic response to DEX was defined based on the best-corrected visual acuity (BCVA) and central macular thickness (CMT) changes after the first DEX, respectively. Steroid-response was defined as intraocular pressure (IOP) elevation >= 5 mmHg or IOP > 21 mmHg after any previous DEX exposure. Pairwise comparisons for BCVA, CMT, and IOP after FAc were performed with linear mixed models and a repeated-measure design. Results Forty-four eyes of 33 patients were included. Patients were shifted to FAc after a mean +/- standard deviation of 4.6 +/- 3.2 DEX injections. Overall, BCVA and CMT improved during the first 12 months after switching to FAc (p = 0.04 and p < 0.001, respectively). Only eyes with a good morphologic response to DEX had a significant CMT reduction after FAc (p < 0.001), while no significant relationship was found between BCVA improvement after DEX and after FAc. IOP elevation occurred in 9 eyes (20%) following DEX implant. These eyes carried a 20-fold increased risk of having an IOP rise after FAc (p < 0.001), with a non-linear relationship between the IOP increase after DEX and the one after FAc. Conclusion The response to previous DEX may anticipate the morphologic response to subsequent FAc. Eyes with steroid-induced IOP elevation after DEX are at a high risk of IOP increase after FAc. The visual response after FAc was not associated with the visual response to previous steroids, indicating that FAc may have a role also in patients refractory to DEX implant.