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These articles will be changed regularly and cannot be reproduced without the prior consent of Glaucoma Australia Inc. Click here to return view previous Articles of the Month index page RESEARCH AND DEVELOPMENT SCAR WARS - IMPROVING GLAUCOMA SURGERY
Eye drops and laser treatments do not always adequately reduce eye pressure in glaucoma. In these cases surgery can be used to reduce the pressure to safe levels. The most common surgery for glaucoma is called "trabeculectomy". In this operation, an opening is created to permit fluid (aqueous humor) to drain out of the eye. The major obstacle to successful surgery, however, is a build up of scar tissue which can block the opening, leading to a build-up of pressure again. Despite the best of operations, strong scarring can completely reverse the benefits of surgery In successful surgery a boggy area can often be seen on the surface of the eye, usually under the upper eyelid. This area, known as a "bleb" contains fluid which has drained out of the eye through the opening created during surgery. In general, the larger the size of the bleb, the more fluid can drain out and the lower the pressure left in the eye. In the images below, a bleb can be seen in the eye on the left (demarcated by arrows). Over a period of months, scar formation has led to a reduction of the size of the bleb (right image). The flow of fluid has become restricted leading to a rise in eye pressure.
Figure 1. The bleb (arrows) in the first few weeks after surgery becomes reduced over time (right) as a consequence of excessive scarring A number of medicines are now available which can reduce the amount of scarring. These drugs are either used during surgery or after surgery in the form of eye drops or injections The most commonly used drugs are steroid eye drops, which can be prescribed for up to six months after surgery to reduce inflammation and scarring. But the biggest weapons in the fight against scarring are called "5-fluorouracil" and "mitomycin-C". These were initially developed for the treatment of cancers. But it was discovered that applying these drugs to the outside of the eye for as little as a few minutes could reduce scar tissue in the long-term. As a consequence, these treatments are now used in the majority of glaucoma operations in countries such as the USA. Although these advances have been a great benefit, trabeculectomy results still vary greatly and many questions remain unanswered. A new Glaucoma Research Laboratory has been set up at Westmead Millennium Research Institute, Westmead Hospital in collaboration with the Wound Healing Research Unit at the Institute of Ophthalmology and Moorfields Eye Hospital in London. It has received a major grant from Glaucoma Australia (through the Ophthalmic Research Institute of Australia). The focus of the research is to improve the way current antiscarring drugs are given as well as discovering new methods for switching off the scarring response after surgery. As excess scarring is currently the biggest hurdle to successful glaucoma surgery, it is hoped that this research will give glaucoma surgeons the know-how to provide a better outcome from glaucoma surgery.
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