Local researchers have discovered a potential new treatment for glaucoma, Hong Kong's leading cause of blindness. A research team at the Chinese University of Hong Kong, which announced its findings yesterday, said the drug Topical Sodium 4-Phenylbutyrate was found to prevent and treat steroid-induced glaucoma in rabbits. It has been used as a treatment for urea cycle disorder, a genetic disorder in which nitrogen accumulates in the form of ammonia, and is unable to be removed from the body. Left untreated, the disorder can lead to brain damage. Now, researchers are hopeful that the compound can be used in eye drops to prevent and treat glaucoma, which is caused by an increase in eye pressure. It leads to progressive damage to the optic nerve and can result in blindness. More than 60 million people have glaucoma worldwide, including 15 million Chinese, said Dr Christopher Leung Kai-shun, associate professor in the university's department of ophthalmology and visual sciences. In Hong Kong, glaucoma has been found to be the leading cause of blindness, accounting for 23 per cent of all cases, according to a previous study. Five glaucoma medications are currently used to lower eye pressure. Some patients may only need one glaucoma medication, but others may require four to five to treat their condition. Professor Dennis Lam Shun-chiu, the study's principal investigator, said the discovery 'can bring hope to steroid-induced glaucoma patients whose eye pressure cannot be controlled with all the currently available medications'. Steroid-induced glaucoma is a preventable condition, which is caused by the use of steroid medications, such as using eye drops or injection of a steroid to cure the infectious eye disease. More than half of all glaucoma patients had sensitivity to steroids, the researchers said. The team expects clinical trials to begin in two or three years.