Abstract: The present invention relates to optically clear polysiloxane-based compositions which are employed, in particular, for the production of contact optical articles such as contact lenses, scleral lenses and intraocular lenses.

Abstract: The invention relates to new cross-linked copolymers of N-vinyl pyrrolidone, N-alkyl-N-vinyl carboxylic acid amides, methacrylates and optionally further copolymerizing monomers of a specific composition. the copolymers have a water absorption capacity of up to about 80% by weight, based on the hydrated state, and are suitable for the production of shaped articles which are in contact with living tissue in use. Examples include soft contact lenses and scleral lenses of high mechanical strength, in particular thin to very thin lenses for prolonged wear.

Abstract: The optical contact objects contain a wettable, optionally crosslinked copolymer comprising the components N-vinylcarboxamide, (meth)acrylates of a polysiloxane and, optionally, vinyl monomers.

Abstract: Contact lenses prepared from a polymer alloy essentially free from low molecular weight plasticizers and which comprises(A) 97-80% by weight of one or more cellulose esters of one or more aliphatic carboxylic acids, and(B) 3-30% by weight of an aliphatic polymeric compound having ester moieties, carbonate moieties or both ester and carbonate moieties in the polymer chain and having an average molecular weight of 2,000 to 300,000, with less than 2% by weight of compounds having a molecular weight below 500.

Abstract: Contact lenses and contact shells of light-refracting material consisting essentially of a copolymer of(I) from 40 to 90% by weight of methyl methacrylate and(II) from 10 to 60% by weight of methyl acrylate and/or esters corresponding to formula (1): ##STR1## in which R represents H or CH.sub.3,R' represents H, CH.sub.3 or C.sub.2 H.sub.5 andn=1 or 2,the sum of I and II amounting to 100% by weight.