Comparison of 577nm Multispot versus standard single-spot photocoagulation for Diabetic Retinopathy

Session Details

Session Title: Free Paper Session 11: Vascular Diseases & Diabetic Retinopathy III

Session Date/Time: Friday 08/09/2017 | 11:00-12:30

Paper Time: 11:00

Venue: Room 114

First Author: : R.Passos BRAZIL

Co Author(s): :    J. Belucio Neto   C. Xavier   E. Novais   M. Maia   M. Farah                 

Abstract Details


To evaluate anatomical and functional outcomes in patients with diabetic retinopathy (DR) treated with panretinal photocoagulation (PRP) with 577nm Multispot laser (Supra Scan® Quantel Medical) vs standard 532nm single-spot laser, comparing laser parameters and patient tolerance.


Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo-SP, Brazil


Single-centre, randomized clinical trial involving 33 eyes with proliferative or severe non-proliferative DR. Eyes previously treated with laser or intravitreous drugs in the past 6 months were excluded. Baseline exams performed were best corrected visual acuity (BCVA), OCT and fluorescein angiography. Patients were then randomly allocated to one of 2 possible treatment arms, 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 tolerance measured through a subjective pain scale


Group 1 (n=15) baseline BCVA 0,5±0,3 and central retinal thickness (CRT) 294,1±102,1μm; treatment was divided in 3,3±0,8 sessions, delivering 2739±616,1 spots. Patients’ reported pain (subjective 1-10 scale) was 5,5±2,1 and photofobia 5,8±2,8. After 6 months, mean BCVA 0,5±0,2 and CRT 243,7±59,9; OCT evidenced induction of posterior vitreous detachment (PVD) in 57,1% of patients, macular edema improved in 71,4%. Group 2 (n=18) baseline BCVA 0,5±0,5 and CRT 353,1±196,4μm; Number of spots 1290,9±238,9 divided in 4,1±0,8 sessions; mean pain 6,1±2,1 and photofobia 6,0 ±2,0. In the 6-month visit, mean BVCA 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%.


577nm multispot laser, compared to 532nm single-spot, requires a smaller number of sessions for completing PRP. By increasing treatment density and delivering a greater number of spots, it compensates for the lower fluency of the short pulse burns. It is also better tolerated by patients due to the lower exposure time, seems to induce PVD and to improve macular edema more frequently, while providing similar angiographic improvements after 6 months. However, the regression of new vessels wasn’t observed in the majority of cases within a 6-month follow-up. This seems to be related to the severity of baseline disease and bad systemic control, rather than the treatment modality employed.

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