Real-world outcomes of naïve, early switch and late switch eyes treated with dexamethasone intravitreal implant for retinal vein occlusion

Purpose To evaluate functional and anatomical outcomes after intravitreal dexamethasone implant (DEXI) in macular edema secondary to retinal vein occlusion (ME-RVO), comparing treatment-naïve eyes with early-switch (ES) and late-switch (LS) eyes previously treated with anti-VEGF, to explore the optimal therapeutic window for switching. Methods A retrospective real-world study including 71 eyes with ME-RVO treated with DEXI and followed for 12 months. Patients were classified as naïve (no prior intravitreal therapy), ES (≤3 anti-VEGF injections before switching), and LS (>3 anti-VEGF injections before switching). Functional outcomes were assessed by best-corrected visual acuity (BCVA), and anatomical outcomes by central macular thickness (CMT) using spectral-domain optical coherence tomography. Results BCVA improved significantly at month 2 in treatment-naïve and ES eyes (p < 0.05), whereas no significant change was observed in LS eyes. A ≥ 2-line gain occurred in 50% of naïve eyes, markedly higher than in previously treated eyes. Naïve patients maintained functional and anatomical improvement throughout follow-up. All groups demonstrated an early reduction in CMT at month 2 ( p < 0.05). Multivariate analysis identified baseline BCVA, but not switching timing, as the main predictor of functional improvement. Conclusions While DEXI improved anatomical outcomes across all subgroups, functional recovery was more frequently observed in naïve and ES eyes. However, baseline BCVA emerged as the main independent determinant of functional response, suggesting that visual outcomes are primarily driven by initial visual status rather than switching timing. By including a naïve comparison group, this study provides novel insights into the management of ME-RVO in patients with suboptimal anti-VEGF response.