New test to detect "sneak theif of blindness" By Damon Shorter A new instrument which diagnoses the devastating eye disease glaucoma more effectively is expected to reach Australian doctors this month. The instrument, based on an idea by ANU visual scientist Ted Maddess, accurately identifies 95 per cent of early glaucoma cases and is quicker, easier to use and approximately half the price of conventional diagnostic machines. Welch Allyn, the US medical instrument company that launched the device in July, says it represents a breakthrough in the detection of early, treatable cases of glaucoma, a disease which affects 2 per cent of the population over 40 and is the third most common cause of blindness in the world. Glaucoma is often referred to as the "sneak thief of blindness" because the degeneration of cells in the retina which causes the disease begins in the periphery of vision and often goes unnoticed until symptoms are quite advanced. Patients may lose up to 30 per cent of their retinal cells and still retain normal reading ability, Dr Maddess said. If untreated, patients develop tunnel vision degenerating into full blindness. A combination of high pressure in the eyeball and restricted blood flow to the retina is thought to destroy the cells that lead into the optic nerve, creating patchy blindness, Dr Maddess said. Current tests for the disease measure the pressure in the eyeball (often normal in glaucoma patients) or use a series of tiny lights to detect holes in the visual field. The pressure test accurately diagnoses only 50 per cent of glaucoma patients and the visual test is long, tedious and accurate in only 9 out of 10 cases. The new instrument, known as frequency doubling perimetry technology (FDT) device, uses an optical illusion to identify glaucoma symptoms. Patients with even minor nerve cell deficits in their retina are unable to recognise the illusion, which is created by switching quickly between alternate patterns of black and white lines on a computer screen. The ANU's commercial arm, ANUTECH, began negotiating to commercialise Dr Maddess' idea for a new glaucoma diagnostic test in 1988. "It is fantastic to see it finally come to fruition because it is a superb technology and its success makes all our combined efforts worthwhile," said Dr Lex Beardsell, ANUTECH's General Manager of Technology and Marketing. Welch Allyn's involvement in the project began in 1990 when they started funding Dr Maddess' research at the Research School of Biological Sciences (RSBS). In 1994 they took over the project and designed the FDT instrument. Dr Maddess was consulted throughout the development process. Humphrey Instruments, the largest international manufacturer of ophthalmic devices, has formed a partnership with Welch Allyn to market the new instrument internationally. Dr Maddess says his commission on instrument sales is unlikely to make him rich but admits he could probably retire from research if the machine sells as well as Welch Allyn are predicting. "I could, but I probably wouldn't," he said. "I'd just keep on doing what I'm doing because it's too much fun."