Pathological elevation of intraocular pressure(IOP)is the most prevalent risk factor in the development and progress of glaucoma. Up to date, all treatments for glaucoma are aimed to lower IOP through surgeries and drugs. Prostaglandin analogues are the first-line IOP-lowing drugs for glaucoma due to their ability to reduce IOP. Enough evidences have suggested that they increase aqueous humor outflow through uveoscleral pathway. More recently, people found that bimatoprost was able to increase aqueous humor outflow through trabecular meshwork-Schlemm's canal pathway. Nowadays, a large number of studies are performed to study the mechanism of prostaglandin analogues on lowing intraocular pressure.