title: Ocular findings at initial pan retinal photocoagulation for proliferative diabetic retinopathy predict the need for future pars plana vitrectomy.
abstract: OBJECTIVE
  To determine the 1-year and 2-year likelihood of vitrectomy in diabetic patients undergoing initial pan retinal photocoagulation (PRP).
  
  
  METHODS
  Diabetic eyes receiving initial PRP for proliferative diabetic retinopathy (PDR) were analyzed to determine their risk for vitrectomy based on clinical findings.
  
  
  RESULTS
  In total, 374 eyes of 272 patients were analyzed. The percentage of eyes undergoing vitrectomy 1 year and 2 years following initial PRP was 19.1% and 26.2%, respectively. Of the eyes in Group 1 (PDR alone), Group 2 (PDR and vitreous hemorrhage), and Group 3 (PDR and iris neovascularization, vitreous hemorrhage with traction or fibrosis, or fibrosis alone), the percentage receiving pars plana vitrectomy at 1 year and 2 years was 9.73% (18/185) and 15.7% (29/185), 26.9% (43/160) and 34.4% (55/160), and 37.9% (11/29) and 48.3% (14/29), respectively. Eyes in Group 2 had 2.78 times greater likelihood (P < 0.0001) and eyes in Group 3 had 3.54 times higher likelihood (P < 0.0001) of requiring pars plana vitrectomy within 2 years than those with PDR alone.
  
  
  CONCLUSIONS
  Eyes receiving PRP for PDR with associated hemorrhage or traction were more likely to undergo pars plana vitrectomy within 1 year and 2 years following initial PRP compared with eyes with only PDR, providing important prognostic information for PRP-naive patients.
authors.affiliation: Departments of *Ophthalmology and Visual Sciences, †Biomedical Informatics, and ‡Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Ravi
authors.initials: R
authors.lastname: Parikh
authors.forename: Rohan J
authors.initials: RJ
authors.lastname: Shah
authors.forename: Jacob P
authors.initials: JP
authors.lastname: VanHouten
authors.forename: Edward F
authors.initials: EF
authors.lastname: Cherney
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000601:surgery*; D005260:Female; D006801:Humans; D007498:Iris / Q000098:blood supply*; D017075:Laser Coagulation; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000175:diagnosis / Q000601:surgery*; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D014821:Vitrectomy / Q000706:statistics & numerical data*; D014823:Vitreous Hemorrhage / Q000175:diagnosis / Q000601:surgery*; D055815:Young Adult