Study results recognize the need for the use of antiscarring agents in Asian eyes, which are known to have a greater propensity to post-operative scarring and as a result can significantly limit the success of the surgery.

Introduction

Glaucoma is a disease of the optic nerve that is characterized by raised eye pressure (intraocular pressure), visual field loss, and characteristic changes to the optic nerve appearance. Glaucoma is the leading cause of irreversible blindness worldwide. The main risk factor for the development and progression of glaucoma is raised intraocular pressure. Topical anti-glaucoma medications are the first line treatment for lowering intraocular pressure. Glaucoma filtration surgery (trabeculectomy), which lowers the eye pressure through the creation of a new channel for the fluid (aqueous humour) to leave the eye, is reserved for cases with intraocular pressures that are insufficiently low on eyedrops alone to preview the disease from progressing and ultimately blindness. Although very effective in reducing eye pressure, the post-operative wound healing response following trabeculectomy can hamper the success of the surgery in the long-term from scar tissue obstructing the flow of aqueous humour out of the eye, with an inevitable rise in intraocular pressure once again. Eye surgeons often use drugs to reduce the scarring response at the time of the surgery. The safety and efficacy of these drugs was not entirely known in Asian eyes.

The Study

To address this, the Singapore National Eye Centre conducted a large clinical study. The Singapore 5-Fluorouracil Trabeculectomy Study is a recently published prospective clinical trial reporting the long-term effects of the use of the antiscarring agent, 5-fluorouracil on safety, surgical outcome and glaucoma disease progression in Asian eyes, in the journal of Ophthalmology, (February issue, volume116, pages 175-84).

It was at the time the largest clinical trial of its kind to be funded by the National Medical Research Council of Singapore. The landmark study of 243 patients took almost a decade to complete and report (5 years recruitment all subjects followed by another 3 years of post surgical follow-up) was conducted at the Singapore National Eye Centre. Local and international collaborating institutions included NUH, TTSH and Moorfields Eye Hospital, London, UK.

Major Results and Clinical Application

The results from the trail report that the use of 5-Fluororacil delays visual field loss, and 5-Fluororacil is safe to be administered at the time of surgery. There was also a reported trend for a greater number of subjects treated with 5-fluorouracil to obtain lower intraocular pressures compared to placebo treatment.

This clinical study conducted at Singapore National Eye Centre is the first and largest report to confirm that glaucoma surgery in Asian Eyes benefit from the use of the antiscarring agent, 5-fluorouracil. In fact antiscarring agents are now a standard treatment given at the time of surgery to improve surgical success.

"More importantly, the results from the study has recognized the need for the use of antiscarring agents in Asian eyes, which are known to have a greater propensity to post-operative scarring and as a result can significantly limit the success of the surgery. In fact, the use of antiscarring agents at the time of surgery are standard in Asian eyes and current practice is such that stronger antiscarring agents than 5-Fluorouracil are now employed," Dr Tina Wong, consultant ophthalmologist with the Glaucoma Service, Singapore National Eye Centre who is also the paper's first author, pointed out.

Research at SERI

"The Ocular Wound Healing and Therapeutics group in Singapore Eye Research Institute continues in its drive to develop new antiscarring strategies and design novel therapeutic drug delivery systems for the management of Asian glaucoma through its Translational Clinical Research (TCR) program which was awarded by the National Research Foundation in 2008", Dr Wong added.

Press Release by Singapore National Eye Centre

For more information and interviews with the study authors at the SNEC, please contact:

Ravi Chandran
Corporate Communications
Singapore National Eye Centre
Tel: 6322 8394
Email: ravi.chandran@snec.com.sg