ABSTRACTImpact performance by the ballistic technique was determined for 720 test ophthalmic lenses including non-treated, beat-treated and chemical-treated glass lenses and plastic lenses. Half of the lenses were abraded on the front surface. Plastic lenses had the greatest impact resistance, while non-treated glass lenses had the least. Chemical-treated and heat-tempered glass lenses offer similar impact protection. All four types lost impact strength after being scratched on the front surface.