Summary

In this article we discuss the non medical management of glaucoma - the various laser and surgical treatments.

Laser Treatment

Laser trabeculoplasty

This involves delivery of laser to the trabecular meshwork to enhance aqueous outflow and consequently lower IOP. There are three types, selective laser trabeculoplasty, argon laser trabeculoplasty, and micropulse laser trabeculoplasty. Laser trabeculoplasty is used in a range of open angle glaucomas, particularly after failure of medical therapy, however particularly SLT with it’s good safety profile is increasingly being used as a primary therapy.

In Selective laser trabeculoplasty, a 532 mm frequency doubled, 1 switched Nd:YAG laser is used to target the melanin pigment in the trabecular meshwork. The energy delivered to the trabecular meshwork is much lower than with argon laser, with mild complications (transient inflammation, peripheral anterior synechiae formation and mild IOP elevation).

In Argon laser trabeculoplasty, the principle is the same as SLT however laser burns are targeted to the trabecular meshwork which receives thermal damage, (therefore repeat treatment is not usually performed unlike SLT). Complications are as for SLT, however can be more severe, including cystoid macular oedema.

Micropulse laser trabeculoplasty (MLT) is a newer technique which uses very short pulses of laser to deliver thermal energy. It is far less damaging, using a much smaller area targeted than SLT.

Laser iridotomy

This is mainly used in the case of primary angle closure glaucoma, but may also be useful in secondary angle closure with pupillary block. A hole is created in the iris, thereby allowing aqueous humour to train directly from the posterior to the anterior chamber, hence relieving pupillary block. In general, Nd:YAG laser achieves better results than argon with less damage to the cornea, lens and retina.