Scientists at UCL (University College London) have developed a more reliable test for detecting vision loss in people with age-related macular disease (AMD), the leading cause of blindness in the UK and US. The method, which centres on a visual illusion, could lead to earlier self-diagnosis of sight deterioration encouraging patients to access medical assistance earlier on and potentially delay loss of vision.
Recent developments in the treatment of AMD mean that vision can be retained in some people with the injection of drugs into the eye, as long as they present to an eye clinic soon after the development of symptoms. These advances mean that accurate diagnosis is increasingly crucial in delaying sight-loss.
The new test, described in the current issue of PLoS ONE, relies on a visual illusion known as the twinkle after-effect, where a moving pattern can be induced in regions of the eye which have vision loss. Previously, this illusion has been demonstrated in normally sighted subjects, by using artificial scotoma (a way of blocking vision in a specific area). This is the first time it has been translated to people with eye disease and the results indicate it could be a powerful diagnostic tool.
Dr Michael Crossland, UCL Institute of Ophthalmology, is one of the researchers involved in this study. He explained: At present, people identified as being at risk of AMD are given a grid chart to observe on a daily basis, and are instructed to attend hospital if they notice any new distortion on this chart.
However, as many as 1 in 2 people will not be able to detect their vision loss using this chart, as the brain fills-in the missing information and perceives the chart as normal, when they actually should see distortion.
The initial data on our test indicates that it is quick, accurate and resistant to the effects of filling-in.
Dr Peter Bex from Harvard Medical School, a co-author on the paper, said: The qua
|Contact: Ruth Metcalfe|
University College London