There are 2 groups of patients who benefit from this treatment.

i) Patients with narrow anterior chamber angles (usually long-sighted individuals) who are predisposed to have acute glaucoma.  In this condition, fluid produced behind the iris cannot escape into the front part of the eye, where fluid is drained out of the eye.  As a result, the pressure in the eye can go extremely high, resulting in sudden loss of vision, pain, redness and vomiting.  By placing a small hole in the iris, fluid can move directly from behind to in front of the iris, which in 98% of the time protects the patient from acute glaucoma.

ii) Patients with Pigment Dispersion Syndrome (PDS).  This condition may lead to a rise in intraocular pressure because of deposition of pigment from behind the iris into the drainage pathways of the eye (anterior chamber angle).  In patients with PDS, the iris is bowed backwards and rubs on the zonular support for the lens.  This releases pigment from the back of the iris.  By placing a small hole in the iris, the shape of the iris is normalised, moving the iris plane away from the lens supporting structures.