Careprost eye drops 0.03% contain bimatoprost, a synthetic analogue (mimic) of the naturally occurring prostamide that has potent ocular hypotensive (pressure reducing) activity and is used to treat glaucoma. The build up of pressure in the eye that is seen in glaucoma is caused by a blockage in the draining system for the eye fluid called aqueous humour, which is produced continually. Although aqueous humour is important for maintaining normal eye pressure and providing nutrients for the eye, increased production or decreased drainage from the eye increases IOP, which can cause damage to the optic nerve fibres that lead out of the back of the eye to the brain and may lead gradual loss of sight. Bimatoprost in Careprost eye drops increases the flow of aqueous humour out of the eye through the spongy tissue called the trabecular network, by opening up the trabecular mesh for fluid drainage. As the flow of fluid into and out of the eye becomes balanced again, the pressure in the eye is lowered and this reduces the risk of damage to the optic nerve and loss of sight that can happen if glaucoma progresses untreated.