US Patent 7326423 Copolymerizable azo compounds and articles containing them

Polymerizable light absorbing azo dyes are disclosed useful as monomers in the formation of devices such as, but not limited to ocular lenses. Specifically, intraocular lenses (IOL) are disclosed wherein one or more of the light absorbing dye is covalently bonded to other structural polymers though ethylene unsaturated groups. The resulting IOLs possess light absorbing properties without significant amounts of free (un-bound) azo dye molecules present in the final structural polymer matrix.