Antiglaucoma medications are the first line therapy for the patients with primary open-angle glaucoma (POAG).As these intraocular pressure (IOP)-lowering agents are used for spanning years,good tolerability and better compliance are desired.Long-term application of antiglaucoma medications may exert side effects on ocular surface,which includes tear film,conjunctiva and cornea.These side effects can be attributable to the preservatives contained in the eye drops,e.g.,benzalkonium chloride (BAK).Preservative-free eye drops,vitamin A palmitate,antimetabolites,and new drug deliveries such as nanoemulsions and cationic emulsions,can contribute to minimizing the side effects as well as promoting the compliance and continuation of medication therapy.