The iStent is inserted into the eye’s natural drainage channel – the trabecular meshwork. The aqueous humour is then able to bypass the trabecular meshwork and drain through the iStent lowering the eye pressure (IOP) as well as the need for glaucoma eye drops. Insertion of the iStent involves a short surgical procedure that is often performed at the same time as cataract surgery, usually as a day case procedure. The implantation of the iStent only adds an addition 5-10 minutes to the surgical time of the cataract surgery. The operation is usually performed under local anaesthetic using eye drops to numb the eye (topical anaesthesia).