PURPOSE: A resin composition that is composed of a copolymer from 2 different kinds of specific monomers, thus being suitably used as optical lenses, because it has high refractive index with reduced color abberatin as well as high light resistance, shock resistance and processability.

CONSTITUTION: The objective composition is composed of a copolymer from 10W90pts.wt. of a monomer of formula I (n is 0W2; X is H, methyl, Cl, Br; Y1, Y2 are H, Cl, Br, I) and 10W90pts.wt. of monomers copolymerizable with the above-cited monomer such as a monomer of formula II (Y1, Y2 are H, methyl Cl, Br; Z1WZ4 are H, Cl, Br; n1, n2 are 0W3), preferably giving a homopolymer of more than 1.55 refractive index.

EFFECT: The resultant resin composition has more than 35 Abbe number and more than 1.55 refractive index.