inner surface of the handle forming a gap 20 the handle also has a window 18 which allows light to pass through the middle portion of the handle referring to fig3 the hydrophobic porous polymer film is a polymer matrix which can be made from the same material used in general surgery for tissue replacement such as products sold under the trademark of gore tex proplast and impra this hydrophobic porous polymers becomes wetted when implanted into the eye in particular several ptfe porous films are custom made by france chirurgie instrument for use as a keratoprosthesis material these polymers were found to be very biocompatible with eye tissues experiments have shown that although body fluids can pass across the polymer matrix cellular in growth in 250 u03bcm thick polymer films having 20 u03bcm pores was extremely slow it usually takes longer than 6 months for cellular in growth to occur eventually fibrocyte cells which have a diameter of approximately 6 u03bcm will invade the implant and obstruct flow by further reducing the pore size to 1 5 u03bcm the cellular in growth is prevented another consideration is that the pores must be larger than 1 u03bcm in order to prevent the forming of proteinic aggregates which are naturally found in aqueous humor of non inflamed human eyes the length of the pore has to be small less than 200 u03bcm to prevent accumulation of proteins and subsequent flow obstruction the pore 39 s surface must be.