Clinical Trials
May 2010

Single-Session vs Multiple-Session Pattern Scanning Laser Panretinal Photocoagulation in Proliferative Diabetic RetinopathyThe Manchester Pascal Study

Author Affiliations

Author Affiliations: Manchester Royal Eye Hospital (Drs Muqit, Henson, Young, Patton, Charles, Turner, and Stanga), and University of Manchester (Drs Muqit, Henson, and Stanga), Manchester, England; and OptiMedica Corporation, Santa Clara, California (Dr Marcellino).




Copyright 2010 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2010

Arch Ophthalmol. 2010;128(5):525-533. doi:10.1001/archophthalmol.2010.60

Objective  To investigate the effects of pattern scanning laser (Pascal; OptiMedica, Santa Clara, California) multispot panretinal photocoagulation given in a single-session (SS-PRP) vs single-spot multiple-session PRP (MS-PRP) on proliferative diabetic retinopathy (PDR).

Methods  Single-center, randomized clinical trial of 40 eyes. Proliferative diabetic retinopathy was treated with a 400-μm spot size in 1500 burns given either as Pascal in 20-millisecond SS-PRP or in 3 sessions (100-millisecond MS-PRP) during a 4-week period. Visual acuity, central subfield retinal thickness (CRT), and 24-2 Swedish interactive thresholding algorithm visual fields were recorded at baseline and 4 and 12 weeks.

Main Outcome Measures  Central subfield retinal thickness, mean deviation, and PDR grade at 12 weeks.

Results  There was a significant increase in mean CRT with MS-PRP (22 μm at 4 weeks, 95% CI, −32.25 to −10.75; 20 μm at 12 weeks, 95% CI, −28.75 to −10.82; P < .001) and no significant increase in the SS-PRP group. The mean deviation increased significantly in the SS-PRP group after 4 weeks (0.73 dB, P = .048), with no significant changes in either group at other points. A positive effect on PDR was observed in 74% of eyes in the SS-PRP group vs 53% in the MS-PRP group (P = .31). Mean treatment time for SS-PRP was 5.04 minutes (SD, 1.5 minutes) compared with 59.3 (SD, 12.7 minutes) in the MS-PRP group (P < .001).

Conclusions  There were no adverse outcomes (CRT, visual acuity, or visual field) from using multispot SS-PRP vs single-spot MS-PRP at 12 weeks postlaser, and treatment times were significantly shorter for multispot SS-PRP. Pascal SS-PRP was as effective as MS-PRP in the treatment of PDR.

Application to Clinical Practice  Twenty-millisecond Pascal SS-PRP may be safely and rapidly performed in 1500 burns with a similar efficacy to conventional MS-PRP.

Trial Identifier  Research and Development Office PIN R00037, Central Manchester University Hospitals Foundation Trust.