Biocompatibility of Nanofilm‐Encapsulated Silicone and Silicone‐Hydrogel Contact Lenses

Abstract

A material placed in or in contact with a biological system, that causes the minimum perturbation that can be tolerated by the host biological system, can be considered to be biocompatible. The major effects caused by a contact lens can be considered to be 1) the blocking of the natural supply of oxygen to the epithelium cells of the cornea, 2) interference with the normal evaporation of water from the tear fluid layer, and 3) hindrance of the normal functions of blinking for replenishing oxygen-saturated tear fluid and removing dead epithelium cells, which result from apoptosis. The encapsulation of a highly oxygen-permeable contact lens by a nanofilm with an imperturbable surface state minimizes all these terms. The encapsulated contact lens can be worn safely in extended wear.

Kinetics ofIn VitroLysozyme Deposition on Silicone Hydrogel, PMMA, and FDA Groups I, II, and IV Contact Lens Materials

“…81 Hence, lysozyme can easily penetrate into the matrix of these lens materials, resulting in increased amounts of deposition than other SH lens materials. The plasma coating on some of the SH lens materials can create an imperturbable surface state, 82,83 which could result in lower adsorption of lysozyme in these materials than when compared with CH lens materials. Thus, because of their unique surface and bulk properties, these newly developed SH lens materials are highly resistant to protein deposition and demonstrate lysozyme kinetic profiles that are similar to that observed with the FDA group I and II materials, in that no plateauing was seen.…”

Effects of poly(2-hydroxyethyl methacrylate) and poly(vinyl-pyrrolidone) hydrogel implants on myopic and normal chick sclera

“…Our goal was to strengthen the sclera in both cases, although the underlying mechanisms were expected to be different. The choice of pHEMA hydrogel was based on their proven ocular biocompatibility as contact lenses (Kidane et al, 1998; Yasuda, 2006). We anticipated fibrous encapsulation of the pHEMA implant, which was not expected to show any substantial degradation over time.…”

Efficacy of an Extraction Solvent Used to Quantify Albumin Deposition on Hydrogel Contact Lens Materials

“…52 However, examination of Tables 3 and 4 clearly indicate that the efficacy of this method in extracting albumin from SH lens materials is lower. The current technique could extract approximately 90% of the albumin deposited on artificially spoiled nonsurface modified Johnson & Johnson SH lenses (galyfilcon A and senofilcon A) (Table 3); however, the current method was not as [67][68][69][70][71] whereas the balafilcon lenses are surface treated in a gas plasma reactive chamber, which transforms the silicone components on the surface of the lenses into hydrophilic silicate compounds. 72,73 Galyfilcon and senofilcon lenses do not require any surface treatment process, as these materials incorporate an internal wetting agent (polyvinyl pyrrolidone), 74 and the etafilcon lens material does not require any surface modification process as it has no siloxane groups incorporated.…”