Optical coherence tomography biomarkers in patients with macular edema secondary to retinal vein occlusion treated with dexamethasone implant

PURPOSE: To evaluate the impact of optical coherence tomography (OCT) biomarkers on intravitreal dexamethasone (DEX) implant clinical outcomes in patients with macular edema secondary to retinal vein occlusion (RVO-ME). METHODS: Retrospective study conducted on a cohort of patients with RVO-ME, either naïve or previously treated, who underwent treatment with DEX implant and had a follow-up of 6 months. Anatomic success was defined as a central retinal thickness (CRT) < 250 μm or a relative reduction of CRT ≥10% from baseline. The primary endpoint was the mean change in CRT from baseline to month-6. Secondary end-points included changes in BCVA, the impact of baseline OCT biomarkers on functional and anatomic outcomes; and the impact of treatment on the different OCT biomarkers. OCT biomarkers associated with functional and anatomic outcomes were estimated using a logistic regression model. RESULTS: Fifty-seven eyes were included in the study. Baseline CRT was significantly decreased from 567.6 ± 226.2 μm to 326.9 ± 141.0 μm at month-6 (p < 0.0001). Baseline BCVA was significantly lower in the eyes with disrupted external limiting membrane (ELM) (mean 40.3 ± 21.3 letters) than in those with non-disrupted (mean 68.6 ± 10.7 letters) or partially-disrupted ELM (mean 59.6 ± 13.2 letters), p = 0.0001 and p = 0.0011, respectively. Baseline BCVA was significantly lower in eyes with > 20 hyperreflective foci (HRF) than in those with < 10 HRF (p = 0.0388). The eyes with disorganization of the retinal inner layers (DRIL) had lower baseline BCVA than those without DRIL (Hodges-Lehmann median difference: − 12.0 letters, 95% CI: − 25.0 to − 5.0 letters, p = 0.0042). At month-6, 26 (45.6%); 24 (42.1%), and 20 (35.1%) eyes achieved a BCVA improvement ≥5, ≥10, and ≥ 15 letters respectively. Forty (70.2%) eyes were classified as anatomic success at month-6. Logistic regression analysis found none factor significantly associated with success in the multivariate analysis. CONCLUSIONS: The results of this study suggested a positive impact of DEX on CRT and BCVA in eyes with RVO-ME. No OCT-biomarkers were identified as predictors of clinical-outcomes. Additionally, presence of DRIL, presence of HRF (> 20), or disrupted ELM were significantly associated with worse baseline BCVA.