Date Published: 29 January 2009
Visionary test a sight for sick eyes
A new method for detecting and managing the debilitating eye disease glaucoma developed by researchers at The Australian National University is set to revolutionise testing for the disease.
The device, called the TrueField Analyser, potentially solves many of the problems associated with current test methods and provides much more information to health professionals in much less time.
Glaucoma and other blinding diseases affect about two per cent of all people over the age of 50 years, impacting around 60 million people worldwide. The new test, developed by Dr Andrew James and Ted Maddess, Head of the Centre for Visual Sciences at ANU, uses multifocal pupillographic perimetry to make diagnosis quicker and more accurate.
“To diagnose and manage blinding diseases such as glaucoma it is necessary to measure how people see across their complete field of vision, a process known as perimetry,” said Dr Maddess.
“Standard perimetry examinations take up to 8 minutes per eye and rely on patients making hundreds of difficult subjective judgments about whether or not they have seen test visual stimuli.
The upshot is that it is very difficult to produce a consistent and dependable result from this type of testing. Because the test is so long and in-depth, about 10% of patients fail to complete a proper perimetry test, even though it is critical to the management or diagnosis of their glaucoma,” he said.
The new method objectively measures the visual fields of both eyes concurrently, using only the responses of the pupils to 88 concurrently presented stimuli. The resulting tiny pupil contractions are monitored by a video camera system. The new test is about twice a fast as conventional methods are and at least as accurate and reproducible. It also provides much more information on brain and retinal function than conventional perimeters and so is of interest to a wider range of health professionals.
Drs Maddess and James will be presenting the results of a study carried out with ANU colleagues, Maria Kolic and Rohan Essex from the new ANU Ophthalmology department at The Canberra Hospital at the 29th annual Australian Neuroscience Society in Canberra on Friday.
The new test, the TrueField Perimeter, is a joint venture between the ANU/ARC Centre of Excellence in Vision Science and an Australian company, Seeing Machines Ltd. The study reported at the conference is about one of a series of large clinical experiments designed to fine tune the TrueField method in the search for the best method. The study found that commerciality viable results were achievable. Subsequent studies have refined the method further. The TrueField has regulatory approval and it is hoped it will be on the market in mid-2009.