Yag Peripheral Iridotmy


Lasers have been used in the treatment of glaucoma for many years and as there are a number of different types of glaucoma so there are a number of different laser treatments available that aim to achieve goals that are specific to the condition. In open angle glaucoma laser treatment can reduce the intraocular pressure (IOP) by increasing outflow of aqueous fluid from the eye (laser trabeculoplasty), or decrease the formation of aqueous fluid (cyclophotocoagulation). In narrow angle glaucoma aqueous outflow is improved via laser iridotomy where a small hole is made in the iris, or via iridoplasty where the iris is tightened and the drainage angle opened.

Laser treatment for closed and narrow angle glaucoma

Laser iridotomy

In this treatment a small hole is made with the laser in order to relieve a narrow or closed angle. The aqueous then passes through the hole inducing the iris to fall back away from the drainage meshwork thus allowing the aqueous to drain freely through the meshwork. Treatment is with the Yag laser, first used in 1984, and no anaesthetic other than numbing eye drops is usually required.

Brown irises are often thicker and may require pre-treatment with a different laser and in this instance anaesthesia other than drops may be required. It is often necessary to perform the treatment on the other eye to prevent a rise in IOP at a later date. In some eyes the iris does not fall back as desired and other treatments are required. Even with a good iris position, the eye may still require medication, or sometimes surgery, to control the IOP. Laser iridotomy is most often used following an attack of acute angle closure (red eye, blurred vision and severe pain are the symptoms of this condition) where the other eye is usually at risk and also requires laser iridotomy to prevent a similar attack.

Peripheral iridoplasty

In an eye that has undergone a laser iridotomy but the iris has not fallen back well, an argon (or frequency doubled Yag) peripheral iridoplasty may be used. Laser is applied to the outer margins of the iris to shrink the iris away from the drainage meshwork and open the drainage angle. Anaesthesia other than drops may be required. Both forms of laser treatment for closed/narrow angle glaucoma require post-laser drops, usually in the form of steroids and perhaps anti-glaucoma drops temporarily or indefinitely.