Total integration of an ocular implant/prosthesis: preliminary in vivo study of a new design

An ocular implant designed to simplify surgical implantation, minimize infection and extrusion, and improve motility when used as a prosthetic replacement for eyes removed because of damage or disease was tested in rabbit eyes. The implant consisted of a silicone sphere with patches of porous silicone elastomer at the natural insertion sites of the extraocular muscles. Nine implants also had patch material around the base of an integral post designed to distribute the weight of and transfer motility to an overlying prosthetic conformer. Six implants without posts had a circular porous patch on the central anterior surface to facilitate closure of the conjunctiva and Tenon's capsule. Biocompatibility and feasibility were tested in rabbit eyes for < or = 1 year. The patches promoted conjunctival ingrowth, leading to positional stability, and facilitated adherence of the extraocular muscles. Patch material around the post or on the anterior conjunctival surface enhanced conjunctival closure and healing. All 15 implants were retained with no signs of migration, conjunctival dehiscence, or extrusion. Motility on forced duction testing was significant in all directions. The materials appeared to be biocompatible, and the design with the post provided good motility, with the potential for improved coordinated eye movement as a result of the specifically localized attachment of the extraocular muscles.