| abstract |
The present invention provides compositions and kits of materials for forming a component of a rigid gas-permeable lens. An exemplary composition comprises a hydroxyl-terminated polyurethane prepolymer having an average of more than one hydroxyl group per molecule comprising: i) the residue of an aliphatic diisocyanate, a block comprising polysiloxane and a block comprising a poly (hydroxide oxide) alkylene), or ii) the residue of an aliphatic diisocyanate, a block comprising a fluoroalkyl or fluoroalkyl ether group, and a block comprising a hydrophobic poly (alkylene oxide). The composition further comprises a free aliphatic diisocyanate and a monomeric polyol, or a propoxylate thereof. The average number of hydroxyl groups of the hydroxyl terminated prepolymer plus the average number of hydroxyl groups of the monomeric polyol, or a propoxylate thereof is between 4.5 and 5.5. The invention also relates to kits of materials comprising elements which, when combined, form the composition. The invention further relates to ocular articles and devices comprising components formed from the compositions or kits. |