title: Therapeutic window of retinal photocoagulation with green (532-nm) and yellow (577-nm) lasers.
abstract: OBJECTIVE
  The 577-nm (yellow) laser provides an alternative to the 532-nm (green) laser in retinal photocoagulation, with potential benefits in macular treatment and through ocular opacities. To assess relative risk of thermomechanical rupture of Bruch's membrane with yellow laser in photocoagulation, the therapeutic window, the ratio of threshold powers for mild coagulation and rupture, was measured.
  
  
  METHODS
  Retinal coagulation and rupture thresholds, visualized ophthalmoscopically, were measured with 577- and 532-nm lasers using 10- to 100-ms pulses in 34 rabbit eyes. Lesions at 1 and 7 days were assessed histologically.
  
  
  RESULTS
  Coagulation threshold with yellow laser was 26% lower than with green laser. The therapeutic window increased linearly with log-duration for both wavelengths with a difference in parallel-slope intercept of 0.36 ± 0.20, corresponding to 8% to 15% wider therapeutic window for yellow wavelength.
  
  
  CONCLUSIONS
  The therapeutic window of retinal photocoagulation in rabbits at 577 nm is slightly wider than at 532 nm, whereas histologically the lesions are similar.
authors.affiliation: Topcon Medical Laser Systems Inc., 3130 Coronado Dr., Santa Clara, CA 94054, USA. csramek@topcon.com
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Sramek
authors.forename: Loh-Shan B
authors.initials: LS
authors.lastname: Leung
authors.forename: Yannis M
authors.initials: YM
authors.lastname: Paulus
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Palanker
mesh_terms: D000818:Animals; D016570:Bruch Membrane / Q000293:injuries* / Q000473:pathology; D017075:Laser Coagulation / Q000295:instrumentation*; D054025:Lasers, Dye / Q000009:adverse effects*; D053844:Lasers, Solid-State / Q000009:adverse effects*; D011817:Rabbits; D012160:Retina / Q000473:pathology / Q000601:surgery*; D012164:Retinal Diseases / Q000601:surgery