To PI or not to PI—That is the Question: When is a Prophylactic Laser Peripheral Iridotomy Justified?

Angle closure glaucoma is uniquely different from open angle glaucoma and many eye diseases—it is preventable. Early diagnosis of a narrow or closed angle before irreversible damage to the trabecular meshwork (TM) has occurred can, in many cases, lead to treatment that changes the anatomy around the angle and its widening, prevention of further damage to the TM and ultimately prevention of elevated IOP and glaucoma. In most cases of angle closure, there is a dominant mechanism of pupillary block that can be treated with laser peripheral iridotomy (LPI). Since often the clinician is not certain whether a prophylactic LPI is indicated, in this review I shall present current data on this subject and some practical recommendations.