YAG Peripheral Iridotomy (YAG PI)

A YAG laser peripheral iridotomy is performed almost exclusively for patients with narrow angles, narrow angle glaucoma, or acute angle closure glaucoma. Aqueous fluid is made in the ciliary body of the eye, which is anatomically situated behind the iris. The aqueous fluid primarily escapes the eye by flowing between the lens and iris of the eye, and then drains via the trabecular meshwork, which is located in the angle of the eye (where the front clear cornea meets the iris, essentially). 

If the flow of aqueous fluid to the drainage angle (trabecular meshwork) is obstructed by a forwardly bowed iris, the patient is said to have narrow angles. This condition may predispose one to an acute episode of angle closure glaucoma. If the angles are never acutely closed, but glaucoma is still present, the patient is diagnosed with narrow angle glaucoma. 

What is involved with a YAG PI?

A YAG PI involves creating a tiny opening in the peripheral iris, allowing aqueous fluid to flow from behind the iris directly to the anterior chamber of the eye. This typically results in resolution of the forwardly bowed iris and thereby an opening up of the angle of the eye.  The narrow or closed angle thus becomes an open angle.

What should you expect with YAG PI treatment?

The YAG PI is completed in the office. Prior to the procedure, the pupil is constricted with an eye medication known as Pilocarpine. The procedure itself is completed with the patient seated at the laser, and requires no sedation. After topical anesthesia eye drops are instilled, a lens is placed on the eye to better control the laser beam. The entire procedure takes only a few minutes. The lens is removed from the eye and vision will quickly return to normal.

Does a YAG PI hurt?

The surface of the eye is numbed with topical anesthetics for this procedure, but the iris is not numbed. Therefore, when the laser beam hits the iris to create the peripheral iridotomy, mild discomfort may occur. In general, only a few very brief episodes of slight discomfort are associated with this procedure. Also, some patients temporarily experience a slight brow ache above the treated eye. However, generally there is no pain involved post-operatively.