Glaucoma

Glaucoma is one of the major causes of preventable, irreversible, blindness in Australia. It is caused most often by raised pressure inside the eye, which leads to a permanent damage of the optic nerve. The mainstay of treatment has been to lower the intraocular pressures. There are many treatment options available, ranging from medical treatments like drops and tablets to surgical options like Selective Laser Trabeculoplasty (SLT), Minimally Invasive Glaucoma Surgery (MIGS), Trabeculectomy and Tube/Shunt surgery.

A trabeculectomy is a surgical procedure in which an external opening is created to the anterior chamber of the eye. This needs to be performed in a hospital setting under a microscope. A partial thickness incision is made through the white of the eye, which gets stitched closed again to form a slow-leaking, trap-door-like opening. This is covered by the conjunctiva (mucus membrane of the eye) and leads to the formation of a small blister on the eye known as a bleb.

The trabeculectomy has a long-standing history as a glaucoma procedure, with good outcomes for the management of intraocular pressure. The unpredictability of the healing after surgery, together with long-term risk of infection and complications like hypotony (too low pressure) or late scaring and failure of the bleb, are the reasons why trabeculectomy is mostly used only in severe glaucoma cases.

The latest approach to glaucoma surgery comes in the form of micro stents that can be placed into the drainage system of the eye. These can be implanted during cataract surgery or as a standalone procedure. They provide good pressure drop in mild to moderate glaucoma cases and often lead to the reduction, and even the cessation, of glaucoma drops.

The procedure is done in a hospital setting under a surgical microscope. Only local anaesthetic is needed to numb the eye. The procedure is comfortable with no pain expected post-operatively.

In severe glaucoma cases, where previous trabeculectomy has failed or is destined to fail, an external device can be placed onto the eye with a tube that extends into the anterior chamber. This device allows for the maintenance of a long-standing bleb, to control the intraocular pressure. Shunt surgery is undertaken in a hospital setting.

Approximately 10% of people with glaucoma have anatomically narrow angles in the front section of the eye. This can lead to a sudden increase in intraocular pressure and cause significant optic nerve damage, known as acute angle-closure glaucoma.

This ocular emergency is treated by creating a small laser opening in the iris. Known as an Iridotomy, this can be placed preventatively in patients that are at risk of developing angle-closure glaucoma. The procedure is painless and is done with topical anaesthetic in the clinic rooms.