Role of subthreshold micropulse photocoagulation using 532 nm green laser for persistent macular edema secondary to branch retinal vein occlusion.

BACKGROUND

Macular edema is a leading cause of vision impairment in patients with branch retinal vein occlusion (BRVO). While anti-vascular endothelial growth factor (anti-VEGF) therapies are commonly used, some patients experience persistent or recurrent edema despite multiple injections. Subthreshold micropulse (STMP) laser therapy using a 532 nm green laser has emerged as a potential alternative treatment.

METHODS

This prospective interventional cohort study included 30 eyes with persistent macular edema secondary to BRVO, unresponsive to at least three prior anti-VEGF injections. Participants underwent 532 nm STMP laser treatment, with follow-up assessments at 1, 3, and 6 months. Primary outcomes measured were changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) over the 6-month period.

RESULTS

The mean baseline BCVA was 0.80 ± 0.24 LogMAR, improving to 0.72 ± 0.34 at 6 months (P < 0.04). CMT significantly decreased from 448 ± 68.77 µm at baseline to 353.23 ± 88.33 µm at 6 months (P < 0.01). Complete resolution of macular edema was observed in 16.67% of eyes at 3 months and 33.33% at 6 months. Rescue laser treatment was required in 20% of eyes at 3 months. No procedure-related complications were reported.

CONCLUSION

The 532 nm STMP laser therapy appears to be a safe and effective treatment for persistent macular edema secondary to BRVO, offering significant anatomical and functional improvements over a 6-month period. Further studies with larger sample sizes and longer follow-up are recommended to validate these findings.