title: Single-session vs multiple-session pattern scanning laser panretinal photocoagulation in proliferative diabetic retinopathy: The Manchester Pascal Study.
abstract: 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-mum 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.
  
  
  METHODS
  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 mum at 4 weeks, 95% CI, -32.25 to -10.75; 20 mum 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: University of Manchester, Manchester Royal Eye Hospital, Oxford Road, Manchester M139WH, England.
authors.forename: Mahiul M K
authors.initials: MM
authors.lastname: Muqit
authors.forename: George R
authors.initials: GR
authors.lastname: Marcellino
authors.forename: David B
authors.initials: DB
authors.lastname: Henson
authors.forename: Lorna B
authors.initials: LB
authors.lastname: Young
authors.forename: Niall
authors.initials: N
authors.lastname: Patton
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Charles
authors.forename: George S
authors.initials: GS
authors.lastname: Turner
authors.forename: Paulo E
authors.initials: PE
authors.lastname: Stanga
mesh_terms: D000328:Adult; D000465:Algorithms; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D017075:Laser Coagulation; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011446:Prospective Studies; D012160:Retina / Q000473:pathology / Q000601:surgery*; D015861:Retinal Neovascularization / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D019233:Retreatment; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields