Abstract
Purpose :
To evaluate anatomical and functional outcomes in patients with diabetic retinopathy (DR) submitted to panretinal photocoagulation (PRP) with 577nm multispot laser (Supra Scan® Quantel Medical) vs 532nm single-spot laser (PASCAL® Topcon), and to compare laser parameters and patient comfort.
Methods :
Single-center, randomized clinical trial involving 48 patients with DR who met criteria for PRP. Eyes with ocular commorbidities or previous intravitreal injection or vitrectomy were excluded. Baseline best corrected visual acuity (BCVA), OCT and fluorescein angiography were performed. Patients were then submitted to PRP, either using 577nm multispot laser with 20ms exposure time (group 1) or 532nm single-spot laser with 100ms exposure time (group 2). Exams were repeated 6 months after treatment. The main outcome was BCVA, and secondary outcomes were FA and OCT changes, laser parameters, number of sessions required for PRP and patient comfort.
Results :
10 patients were excluded and 5 have not yet completed treatment. Group 1 included 15 patients; baseline mean BCVA was 0,5±0,3 and central retinal thickness (CRT) was 294,1±102,1μm; treatment was divided in 3,3±0,8 sessions, delivering 2739±616,1 spots. Patients reported discomfort during PRP as a subjective scale from 0 to 10; mean pain was 5,5±2,1 and photofobia was 5,8±2,8. After 6 months, mean BCVA was 0,5±0,2 and CRT was 243,7±59,9; OCT evidenced induction of posterior vitreous detachment (PVD) in 57,1% of patients, and macular edema improved in 71,4%. Group 2 included 18 patients; baseline mean BCVA was 0,5±0,5 and CRT was 353,1±196,4μm; 1290,9±238,9 spots were produced in 4,1±0,8 sessions; mean pain was 6,1±2,1 and photofobia was 6,0 ±2,0. In the 6-month visit, mean BVCA was 0,7±0,6; OCT showed PVD induction in 37,5% of patients, and macular edema improved in 50%. Angiographic evaluation 6 months after PRP in group 1 showed reduction of vasculitis and non-perfusion areas in 71,4% of patients and regression of new vessels in 28,7%; those numbers in group 2 were, respectively, 75% and 50%.
Conclusions :
577nm multispot laser, compared to 532nm single-spot, requires a smaller number of sessions for completing PRP (using higher treatment density), is better tolerated by patients, seems to induct PVD and to improve macular edema more frequently, and provides similar angiographic improvements.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.