title: Intraocular silicone implant to treat chronic ocular hypotony-preliminary feasibility data.
abstract: OBJECTIVE
  Ocular hypotony secondary to proliferative vitreoretinopathy-related retinal detachment, trauma or inflammation is difficult to treat. Besides endotamponades such as silicone oil, vitreous implants such as iris diaphragms or balloons have been developed to stabilize the eye and to prevent phthisis of the globe. Vitreous implants tested thus far exhibit a seam at the attachment site of the hemispheres, or micropores. This manuscript reports the development of a seamless silicone balloon implant without micropores, which can be filled with silicone oil and surface-modified to improve its biocompatibility. Developed for intraocular placement in the management of chronic hypotony and phthisis prevention, it may also be suitable for tamponading retinal detachments.
  
  
  METHODS
  Silicone was used as the basic structure for the fabrication of a seamless balloon-shaped intraocular implant, which was coated by employing a six-arm star-shaped (sP) macromer of a copolymer of 80 % ethylene oxide (EO) and 20 % propylene oxide (PO) with conjugated functional terminal isocyanate groups, NCO-sP(EO-stat-PO), with and without heparin. Three variants of implants, which differ in their surfaces, were manufactured: uncoated silicone, NCO-sP (EO-stat-PO) coated silicone and heparin-NCO-sP (EO-stat-PO) coated silicone implants. To exert a tamponade effect, the implant was filled with silicone oil and its properties were studied.
  
  
  RESULTS
  Seamless thin balloon implants made of silicone, which are considered biocompatible and intrinsically resistant to biological attacks in vivo, could be fabricated in different sizes. The silicone oil-filled implant can mimic the mechanism of buoyant force and high surface tension of silicone oil, which is the only long-term vitreous substitute currently available. The silicone oil-filled implant can also mimic the natural vitreous body by occupying the entire posterior segment.
  
  
  CONCLUSIONS
  The intraocular silicone implant as an alternative long-term treatment of chronic ocular hypotony might offer a new option for clinical ophthalmological practice. In vivo studies need to be performed to collect more data on the implant's long-term mechanical and optical properties, as well as long-term biocompatibility.
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.|Klinikum Dortmund gGmbh, Dortmund, Germany.
authors.forename: Wesal
authors.initials: W
authors.lastname: Bayoudh
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.|ACTO Aachen Center for Technology Transfer in Ophthalmology, Aachen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Frentz
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Dörthe
authors.initials: D
authors.lastname: Carstesen
authors.affiliation: Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Dittrich
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.|Department of Ophthalmology, Klinikum Köln-Merheim, Köln, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Reismann
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.|ACTO Aachen Center for Technology Transfer in Ophthalmology, Aachen, Germany.|Department of Ophthalmology, Klinikum Köln-Merheim, Köln, Germany.
authors.forename: Norbert F
authors.initials: NF
authors.lastname: Schrage
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Walter
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany. aweinberger@ukaachen.de.|Augenklinik Starnberg, Starnberg, Germany. aweinberger@ukaachen.de.
authors.forename: Andreas W A
authors.initials: AW
authors.lastname: Weinberger
mesh_terms: D001672:Biocompatible Materials; D002908:Chronic Disease; D005240:Feasibility Studies; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008422:Materials Testing; D015814:Ocular Hypotension / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D019736:Prostheses and Implants; D011474:Prosthesis Design; D012828:Silicones; D014821:Vitrectomy / Q000379:methods; D018630:Vitreoretinopathy, Proliferative / Q000150:complications* / Q000175:diagnosis / Q000601:surgery
chemical_list: D001672:Biocompatible Materials; D012828:Silicones
keywords: Intraocular implant; Ocular hypotony; Ocular silicone balloon implant; Proliferative vitreoretinopathy; Retina surgery; Vitreous substitute