A resin having excellent ophthalmic lens performance was produced by radical polymerization of a mixture of bifunctional methacrylate, such as tetraethylene glycol dimethacrylate or triethylene glycol dimethacrylate, a styrenic monomer such as styrene or alpha-methylstyrene, and acrylonitrile. We provide a totally balanced resin composition suitable for an ophthalmic lens, having a high refractive index, large Abbe number, high impact strength, low specific gravity, heat resistance, cutting processability, tintability, and durability.