Visible light absorbers for ophthalmic lens materials

An azo compound of the formula

• wherein
• R1=C(O)CH═CH2, C(O)C(CH3)═CH2, C(O)NHCH2CH2OC(O)C(CH3)═CH2, or C(O)NHC(CH3)2C6H4C(CH3)═CH2;
• R2=H, C1-C4 alkyl, or C1-C4 alkoxy;
• R3=H, C1-C4 alkyl, F, Cl, Br, CN, NO2, COOR4;
• XOC(O)CH═CH2, XOC(O)C(CH3)═CH2, XOC(O)NHCH2CH2OC(O)C(CH3)═CH2, or XOC(O)NHC(CH3)2C6H4C(CH3)═CH2;
• R4=H or C1-C4 alkyl;
• and
• X=C1-C4 alkyl or C2-C4 alkenyl.