Lacritin is a naturally occurring tear protein with antimicrobial activity that is capable of stimulating mitogenesis in human corneal epithelial cells and promoting production of tears in lacrimal gland acinar cells. A recently developed immunoassay for lacritin may help characterize the lacritin response following refractive surgery with the possible development of recombinant lacritin as a novel therapeutic agent for wound healing. Heparanase (HPSE) acts as a regulator for lacritin by cleaving heparan sulfate chains and allowing lacritin to bind. We aim to measure both tear lacritin and HPSE pre- and post-operatively to elucidate lacritin and HPSE's response in patients undergoing PRK (photorefractive keratectomy) and LASIK (Laser-assisted in situ keratomileusis) at the Walter Reed Center for Refractive Surgery.