title: In vitro and in vivo comparison of two suprachoroidal shunts.
abstract: OBJECTIVE
  To compare fibrosis, aqueous humor dynamics, and intraocular pressure (IOP) of two suprachoroidal shunts as part of a new class of glaucoma drainage devices.
  
  
  METHODS
  Following proliferation analysis in vitro, 20 rabbits were implanted with either a gold shunt (GS, GMSplus+, SOLX) or a polypropylene shunt (PS, Aquashunt, OPKO). Ten eyes received mitomycin C (MMC) and triamcinolone. Peak and trough IOP were monitored with a pneumatonometer and tono-pen for 15 weeks. Aqueous humor dynamics were evaluated fluorophotometrically and tonographically. Fibrosis was quantified.
  
  
  RESULTS
  In vitro proliferation was similar. In vivo, both shunts were devoid of foreign body reaction but exhibited fibrosis, and GS showed vascularization. There was no significant difference in aqueous or uveoscleral flow. Preoperative morning IOP was 23.7 ± 2 mm Hg, and evening IOP was 26.5 ± 2 mm Hg (P = 0.000). Morning IOP was decreased through 15 weeks and evening IOP through 8 weeks in all groups. The morning IOP decrease was most profound at 15 weeks in PS (41%) compared to GS (18%). Antifibrotics initially enhanced but eventually diminished shunt performance. At 15 weeks, thickness of scleral fibrosis was greater in GS (246 ± 47 μm) and PS (188 ± 47 μm, P = 0.285) compared with GS+MMC (109 ± 26 μm, P = 0.023 to GS) and PS+MMC (48 ± 30 μm, P = 0.028 to PS).
  
  
  CONCLUSIONS
  In a rabbit model, suprachoroidal polypropylene and gold shunts allow access to a new drainage pathway with different IOP profiles that can be modified with antifibrotics.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Yale University School of Medicine, 300 George Street, Suite 8100, New Haven, CT 06511, USA. julius.oatts@yale.edu
authors.forename: Julius T
authors.initials: JT
authors.lastname: Oatts
authors.forename: Ze
authors.initials: Z
authors.lastname: Zhang
authors.forename: Harry
authors.initials: H
authors.lastname: Tseng
authors.forename: M Bruce
authors.initials: MB
authors.lastname: Shields
authors.forename: John H
authors.initials: JH
authors.lastname: Sinard
authors.forename: Nils A
authors.initials: NA
authors.lastname: Loewen
mesh_terms: D000818:Animals; D002829:Choroid / Q000601:surgery*; D004195:Disease Models, Animal; D015590:Fluorophotometry; D005901:Glaucoma / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D007429:Intraocular Pressure / Q000502:physiology*; D011474:Prosthesis Design; D011817:Rabbits; D014065:Tonometry, Ocular; D016896:Treatment Outcome
keywords: glaucoma drainage device; rabbit; suprachoroidal shunt