Predictive impact of optical coherence tomography biomarkers in anti-vascular endothelial growth factor resistant macular edema treated with dexamethasone implant

Purpose: To perform a longitudinal analysis of the effect of optic coherence tomography (OCT) biomarkers on macular thickness in patients with persistent macular edema secondary to diabetes mellitus and retinal vein occlusion who recieved intravitreal dexamethasone (DEX) implant. Methods: Eighty-nine patients were included in the retrospective study. Patients with anti-VEGF-resistant macular edema were included in the study. The effect of the presence or absence of OCT biomarkers before intravitreal DEX implant therapy on central foveal thickness (CFT) was evaluated. In addition, the change in biomarkers from the baseline visit to the final visit was evaluated. The evaluated OCT biomarkers were as follows: ellipsoid zone and external limiting membrane (ELM) integrity, hyperreflective foci (HRF), disorganization of inner retinal layers (DRIL), hard exudates, serous macular detachment (SMD), pearl necklace, posterior vitreous detachment and the epiretinal membrane (ERM). Results: The mean age of the overall sample in the study was 64.4 +/- 9.6. CFT decreased significantly from 625.3 +/- 22.3 mu m at baseline to 365.0 +/- 21.7 mu m in the 1st month but increased significantly to 430.2 +/- 22.6 mu m in the 3rd month. In the presence of HRF and SMD, recurrence of macular edema was significant in the 3rd month. The percentage of ELM disruption, DRIL, and ERM deteriorated significantly and the percentage of SMD improved significantly at the final visit. Conclusions: DEX implant therapy resulted in a satisfactory reduction in CFT in patients with DME and RVO. The presence of HRF and SMD is a negative predictor of recurrence in CFT in short term. DEX implant therapy resulted in satisfactory improvement in SMD.