Surgery is an effective way to lower IOP, and in some cases it can normalise pressure for a period of time without the use of medications. However, surgery is only rarely chosen first as a treatment option due to the risk of complications in eyes affected by diabetes and eyes not affected by diabetes.
Most surgical procedures for glaucoma lower IOP by reshaping tissue to clear blockages, or by opening new channels for aqueous humour to drain. Less frequently, surgery is used to decrease aqueous humour production by reshaping the ciliary body, the part of the eye where aqueous humour is produced.
Glaucoma drainage devices or “aqueous shunts” are used to enhance standard glaucoma surgery by positioning a device that will help keep the surgically-created drainage opening from healing and closing down. Many current implants include a tube through which the aqueous fluid passes. Others are solid and promote the flow of fluid along the surface of the implant.