Latanoprost, a derivative of the chemical, prostaglandin F2-alpha, is used for the treatment of glaucoma. Glaucoma is a condition in which the pressure exerted by the liquid within the eyeball (the aqueous humor) is too great. The high pressure damages the optic nerve at the back of the eye. The damage interferes with the ability of the nerve to transmit visual images from the eye to the brain and thus can lead to blindness. Prostaglandins control the flow of the aqueous humor out of the eye. Latanoprost, by binding to a specific receptor for prostaglandin, increases the flow of aqueous humor out of the eye, thereby reducing the pressure within the eye and reducing the risk of nerve damage and blindness. When latanoprost and timolol (Timoptic) (a different drug that also is used to treat glaucoma) are used in combination, there is a greater reduction in pressure than when either drug is used alone.