Switch of Intravitreal Therapy for Macular Edema Secondary to Retinal Vein Occlusion from Anti-VEGF to Dexamethasone Implant and Vice Versa

Purpose. To evaluate the anatomical and functional outcome of intravitreal dexamethasone implant for macular edema secondary to central (C) or branch (B) retinal vein occlusion (RVO) in patients with persistent macular edema (ME) refractory to intravitreal antivascular endothelial growth factor (VEGF) treatment compared to treatment naive patients and to dexamethasone-refractory eyes switched to anti-VEGF. Methods. Retrospective, observational study including 30 eyes previously treated with anti-VEGF (8 CRVO, 22 BRVO, mean age 69 +/- 10 yrs), compared to 11 treatment naive eyes (6 CRVO, 5 BRVO, 73 +/- 11 yrs) and compared to dexamethasone nonresponders (2 CRVO, 4 BRVO, 69 +/- 12). Outcome parameters were change in best-corrected visual acuity (BCVA) and central foveal thickness (CFT) measured by spectral-domain optical coherence tomography. Results. Mean BCVA improvement after switch to dexamethasone implant was 4 letters (p = 0.08), and treatment naive eyes gained 10 letters (p = 0.66), while we noted no change in eyes after switch to anti-VEGF (p = 0.74). Median CFT decrease was most pronounced in treatment naive patients (-437 mu m, p = 0.002) compared to anti-VEGF refractory eyes (-170 mu m, p = 0.003) and dexamethasone-refractory eyes (-157, p = 0.31). Conclusions. Dexamethasone significantly reduced ME secondary to RVO refractory to anti-VEGF. Functional gain was limited compared to treatment naive eyes, probably due to worse BCVA and CFT at baseline in treatment naive eyes.