Subretinal injection of balanced salt solution for macular edema secondary to retinal vein occlusion

To investigate the efficacy and safety of subretinal balanced salt solution (BSS) injections for macular edema secondary to retinal vein occlusion (RVO-ME).

We retrospectively analyzed 19 eyes of 19 patients characterized by Retinal vein occlusion (RVO) diagnosed using retinal angiography and persistent or recurrent edema on optical coherence tomography after at least three standard-dose anti-vascular endothelial growth factor (VEGF) treatments. The operation group received pars plana vitrectomy (PPV) combined with internal limiting membrane (ILM) peeling and subretinal injection of BSS. The injection group continued to receive intravitreal injection of anti-VEGF drugs. The results of visual acuity, retinal morphology, and recurrence were analyzed and compared between the two groups after treatment. Statistical comparisons were adjusted for baseline imbalances using analysis of covariance.

After adjustment for baseline best corrected visual acuity (BCVA) and prior injection number, the difference in final BCVA between the surgery and injection groups was not statistically significant (p = 0.081). However, the surgery group demonstrated a statistically significant reduction in final Central macular thickness after adjustment (adjusted mean: 222.67 μm vs. 270.60 μm, p = 0.048). The surgery group also showed a strong trend toward a lower recurrence rate (40.0% vs. 88.9%, p = 0.051) and a longer median time to recurrence (10.0 vs. 4.0 months), though the latter was not statistically significant (log-rank p = 0.503). No serious adverse events were observed.

This preliminary study suggests that PPV combine with ILM peeling and subretinal BSS injection was feasible and associated with significant anatomical improvement in refractory RVO-ME. The procedure has shown potential in controlling edema and reducing recurrence. While visual outcomes were comparable to anti-VEGF after adjustment, the anatomical benefit warrants further investigation in prospective trials.