This procedure is often recommended in eyes with angle closure where a relative pupillary block prevents the flow of fluid from the posterior chamber into the anterior chamber (see Angle closure glaucoma).
Herein an opening is made in the iris with a laser machine for the fluid to drain from the posterior to the anterior chamber of the eye, bypassing the pupillary block. This procedure is done in eyes with narrow angle to prevent an angle closure attack and also as a treatment if the patient is having an acute attack.
