Optical Coherence Tomography Biomarkers in Patients With Macular Edema Secondary to Retinal Vein Occlusion

Abstract

\n Purpose: To evaluate the impact of optical coherence tomography biomarkers on intravitreal dexamethasone (DEX) implant clinical outcomes in patients with macular edema (ME) secondary to retinal vein occlusion (RVO). Additionally, the effect of DEX on central retinal thickness (CRT) and visual acuity (BCVA) was also evaluated. Methods: Retrospective study conducted on a cohort of patients with ME secondary to RVO, either naïve or previously treated, who underwent treatment with DEX implant and had a minimum follow-up of 6 months. Success was defined as a CRT < 250µm or a relative reduction of CRT ≥ 10% from baseline. Results: Fifty-seven eyes were included in the study. 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. Among the 35 eyes with subretinal fluid (SRF) at baseline, those with a SRF thickness > median (119 µm) had a worse baseline BCVA than those with a SRF thickness ≤ median (Hodges-Lehmann median difference: -15.0 letters, 95% CI: -30.0 to -5.0 letters, p=0.0061). 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). CRT was significantly decreased from 567.6±226.2 µm at baseline to 326.9±141.0 µm at month 6 (p<0.0001). 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 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 with no differences between central RVO and branch RVO eyes or between treatment-naïve eyes and those previously treated. DEX implant significantly reduced the presence of cysts and their volume. Additionally, greater amount of SRF, presence of DRIL, presence of HRF (>20), or disrupted ELM were significantly associated with worse baseline BCVA.