title: Methods, statistical features, and baseline results of a standardized, multicentered ophthalmologic surgical trial: the Silicone Study.
abstract: This article describes the trial design and baseline results for the Silicone Study, a multicenter, randomized surgical trial designed to compare the effectiveness of silicone fluid versus long-acting gas in the treatment of proliferative vitreoretinopathy (PVR). Design features include (1) standardization of the surgical protocol to reduce intersurgeon variability, (2) formulation of a PVR clinical classification system relevant to modern vitreoretinal surgery, and (3) creation of a photographic protocol to document PVR pathology. Statistical issues affecting the analysis of the outcome data include (1) the addition of a second group of patients with more severely diseased eyes after the trial began, (2) the change to a different long-acting gas during the course of the trial, and (3) recurrent retinal detachments that require reoperations with the randomized treatment, and, in some instances, a crossover from the randomized to the alternate treatment. Demographic and baseline ocular characteristics are presented for the two groups under study.
authors.affiliation: Department of Ophthalmology, University of Southern California, Los Angeles 90033.
authors.forename: S P
authors.initials: SP
authors.lastname: Azen
authors.forename: D C
authors.initials: DC
authors.lastname: Boone
authors.forename: W
authors.initials: W
authors.lastname: Barlow
authors.forename: B W
authors.initials: BW
authors.lastname: McCuen
authors.forename: A F
authors.initials: AF
authors.lastname: Walonker
authors.forename: M M
authors.initials: MM
authors.lastname: Anderson
authors.forename: J S
authors.initials: JS
authors.lastname: Lean
authors.forename: R L
authors.initials: RL
authors.lastname: Mowery
authors.forename: S J
authors.initials: SJ
authors.lastname: Ryan
authors.forename: W
authors.initials: W
authors.lastname: Stern
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002568:Certification; D004282:Documentation; D005128:Eye Diseases / Q000628:therapy; D005260:Female; D005740:Gases / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009885:Ophthalmology / Q000379:methods* / Q000592:standards; D010781:Photography; D011183:Postoperative Complications; D012086:Reoperation; D012107:Research Design; D012163:Retinal Detachment / Q000209:etiology / Q000628:therapy*; D012164:Retinal Diseases / Q000628:therapy; D012828:Silicones / Q000627:therapeutic use; D014822:Vitreous Body
chemical_list: D005740:Gases; D012828:Silicones