Abstract: A process of making soft lenses from an esterifiable, partially cross-linked carboxyl-containing polymer, and a method of attaching a haptic to a swellable intraocular lens. The soft contact lenses are made by first forming a lens button from a hard polymer containing .alpha.,.beta.-ethylenically unsaturated carboxylic acid such as acrylic or methacrylic acid and 0.1-10 mols per 100 mols of monomer of a divinyl cross-linking agent such as 1,4-butanediol dimethacrylate. The hard lens button is then esterified by contact with an alcohol having up to 15 carbon atoms such as n-butanol under esterifying conditions in the substantial absence of water while simultaneously removing water of reaction. Unreacted alcohol may be removed by solvent exchange with a lower molecular weight alcohol and/or drying.