The iStent is the smallest medical device implantable in the human body. For patients who have manage their glaucoma with medication but need cataract surgery, the iStent can help fix two problems at once. The iStent can lower IOP and lessen the need for glaucoma medication. The iStent creates a bypass in the eye’s natural drainage pathway. This permanent bypass improves the eye’s natural outflow of fluid to lower intraocular pressure.