Subthreshold Grid Laser Treatment of Macular Edema Secondary to Branch Retinal Vein Occlusion With Micropulse Infrared (810 Nm) Diode Laser

Purpose: To evaluate the effectiveness of subthreshold grid laser therapy with infrared micropulse 810 nm diode laser in the treatment of macular edema secondary to branch retinal vein occlusion (BRVO). Methods: In a prospective, randomized clinical trial, thirty–six patients with macular edema secondary to BRVO were randomized either to infrared subthreshold (no intraoperative visible endpoint) grid laser treatment, or to conventional threshold (visible endpoint) grid laser treatment with 647 nm krypton laser. The primary outcome measure was the number of eyes that gained at least 10 letters (approximately 2 or more lines of visual acuity gain) at the 12– and 24–month examinations in the two groups. Results: By the month–12 visit, an improvement of at least 2 lines of visual acuity was registered in 59% and 58% of patients treated using infrared subthreshold grid and using krypton laser, respectively. A gain of at least 2 lines of visual acuity was registered in 64% and 58% of patients treated using infrared subthreshold grid and using krypton laser, respectively, by the month–24 examination. Interestingly, no clinically or angiographically visible sign of the administered laser spots was detectable after subthreshold grid laser treatment. Conclusions: Subthreshold infrared micropulsed grid laser treatment is as effective as krypton grid laser treatment in improving visual acuity in patients affected by macular edema secondary to BRVO.