Early Retinal and Choroidal Coat Thickness Changes after Intravitreal Dexamethasone Implant Injection for Diabetic Macular Edema

BACKGROUND: Intravitreal steroid injection is one of the treatment options for diabetic macular edema. Dexamethasone implant is the most novel form of intravitreal steroid therapy. Improvement in macular thickness is a well-known effect of Dexamethasone implant however, subfoveal choroidal coat thickness changes require investigation. AIMS: To evaluate the early central macular thickness and subfoveal choroidal thickness alterations after single-dose dexamethasone implant injection in diabetic macular edema. STUDY DESIGN: Cross-sectional study. METHODS: We identified 29 patients with diabetic macular edema (29 eyes) who underwent optical coherence tomography and fundus fluorescein angiography. All patients received a single-dose intravitreal Dexamethasone implant and were followed up for central macular thickness and subfoveal choroidal thickness alterations for 1 hour, 1 week, 1 month, and 3 months post-injection. RESULTS: The preoperative mean central macular thickness and subfoveal choroidal thickness measurements were 592.3±122.3 (412–879) μm and 264.8±53.7 (165–397) μm, respectively. Central macular thickness measurements decreased significantly in the first hour (p<0.050) and continued to decrease until the third month (p<0.001), whereas the subfoveal choroidal thickness decrement was only significant on the first day (p<0.05). Decreases in subfoveal choroidal thickness and central macular thickness of 1.5% and 5% were observed at 1 hour; however, the difference was not significant (p>0.050). The decrease in central macular thickness was significantly greater than that in subfoveal choroidal thickness at 1 day, 1 week, 1 month, and 3 months (p<0.001). CONCLUSION: Intravitreal Dexamethasone implant has a meaningful effect on central macular thickness in patients with diabetic macular edema, while subfoveal choroidal thickness decreases significantly at first day.