title: Experience with the Pascal® photocoagulator: an analysis of over 1,200 laser procedures with regard to parameter refinement.
abstract: OBJECTIVE
  To systematically refine and recommend parameter settings of spot size, power, and treatment duration using the Pascal® photocoagulator, a multi-spot, semi-automated, short-duration laser system.
  
  
  METHODS
  A retrospective consecutive series with 752 Caucasian eyes and 1242 laser procedures over two years were grouped into, (1) 374 macular focal / grid photocoagulation (FP), (2), 666 panretinal photocoagulation (PRP), and (3) 202 barrage photocoagulation (BP). Parameters for power, duration, spot number, and spot size were recorded for every group.
  
  
  RESULTS
  Power parameters for all groups showed a non-gaussian distribution; FP group, median 190 mW, range 100 - 950 mW, and PRP group, median 800 mW, range 100 - 2000 mW. On subgroup comparison, for similar spot size, as treatment duration decreased, the power required increased, albeit in a much lesser proportion than that given by energy = power x time. Most frequently used patterns were single spot (89% of cases) in FP, 5 Χ 5 box (72%) in PRP, and 2 Χ 2 box (78%) in BP. Spot diameters as high as ≈ 700 μm on retina were given in the PRP group. Single session PRP was attempted in six eyes with a median spot count of 3500.
  
  
  CONCLUSIONS
  Overall, due to the small duration of its pulse, the Pascal® photocoagulator tends to use higher powers, although much lower cumulative energies, than those used in a conventional laser. The consequent lesser heat dissipation, especially lateral, can allow one to use relatively larger spot sizes and give more closely spaced burns, without incurring significant side effects.
authors.affiliation: Department of Ophthalmology, University of Udine, Udine, Italy. saumil_sheth@hotmail.com
authors.forename: Saumil
authors.initials: S
authors.lastname: Sheth
authors.forename: Paolo
authors.initials: P
authors.lastname: Lanzetta
authors.forename: Daniele
authors.initials: D
authors.lastname: Veritti
authors.forename: Ilaria
authors.initials: I
authors.lastname: Zucchiatti
authors.forename: Carola
authors.initials: C
authors.lastname: Savorgnani
authors.forename: Francesco
authors.initials: F
authors.lastname: Bandello
mesh_terms: D001331:Automation; D048909:Diabetes Complications / Q000601:surgery*; D003930:Diabetic Retinopathy / Q000601:surgery*; D006801:Humans; D017075:Laser Coagulation / Q000295:instrumentation* / Q000592:standards / Q000706:statistics & numerical data; D008269:Macular Edema / Q000601:surgery*; D016011:Normal Distribution; D012167:Retinal Perforations / Q000601:surgery*; D012189:Retrospective Studies; D013997:Time Factors; D044465:White People