Abstract: A novel calcium fluoroaluminosilicate glass consisting essentially of from 25 to 35% by weight of silicon calculated as silica, from 30 to 40% by weight of aluminum calculated as alumina, from 20 to 35% by weight calcium, calculated as calcium oxide, and up to 9% by weight fluorine (preferably 4-7%) can be associated with a poly(carboxylic acid) e.g. as an intimate mixture of glass and acid to constitute a composition curable on contact with water and useful, for example, as a loading on a splinting bandage. Such a bandage preferably has a ratio of set time to gel time from 4:1 to 8:1 with a minimum gel time of 60 seconds.

Abstract: A copolymeric hydrogel for contact lenses with physiological saline uptake 65-85% is formed from an N-vinyl lactam e.g. N-vinyl-2-pyrrolidone and up to 15% of a hydrophobic comonomer of formula ##STR1## where R.sup.1 is H or C.sub.1 -C.sub.4 alkyl (preferably methyl) X is --O-- or --NH-- and R.sup.2 is aryl, C.sub.1 -C.sub.6 alkyl substituted by aryl or aryloxy, or C.sub.1 -C.sub.6 alkoxy substituted by aryl or aryloxy. Preferably the aryl or aryloxy group contain one or two six-membered carbocyclic aromatic rings; they may be C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, or halogen, substituted. Crosslinking agents used preferably have their two functional groups differing in reactivity e.g. allyl, or 3-allyloxy-2-hydroxypropyl, methacrylates.

Abstract: Water-swellable lightly cross-linked copolymers, specifically terpolymers, between 3-methoxy-2-hydroxy-propyl methacrylate (G-MEMA), at least one N-vinyl lactam and at least one copolymerizable monomer to increase strength and stiffness, have utility as contact lenses. Preferred examples contain methyl methacrylate (MMA) and vinylpyrrolidone (VP) as comonomers, and up to 5% e.g. 2% of a cross-linking agent, preferably with non-equivalent functional groups such as allyl methacrylate. Preferably the water content is up to 65% based on total gel, e.g. 50-60% by weight; the VP:MMA ratio is from 50:50 to 70:30 and from 10-75% by weight G-MEMA units are present.