Researchers at Glasgow Caledonian University (GCU) are developing a new eye test which they hope can be used to diagnose glaucoma at an early stage.
Current optometry tests often cannot pick up the eye condition until it is at a relatively advanced stage, by which time there is significant nerve damage to the eye.
With funding from the College of Optometrists, GCU PhD researcher, Michelle Snowball, is trialling a computer-based test that measures whether people can manage to spot subtle differences between circles.
The test has been developed by GCU Professor of Visual Neuroscience Gunter Loffler and his colleagues, Drs Graeme Kennedy and Gael Gordon. The research team is planning to run it on a range of patients – both with glaucoma and without – to determine if shape perception is adversely affected in glaucoma.
The test is based on being able to spot the difference between circles, some of which have a ‘deformed’ part, on a computer screen. Early lab trials have proved promising, with glaucoma detected through the shape test in both eyes of a patient who believed it had only affected one of his eyes.
Michelle said, ‘If untreated, glaucoma first causes peripheral vision loss. One of the standard ways to measure peripheral vision during a routine eye exam is by showing lights of different brightness at various points in a patient’s visual field and asking them to press a button if the light was seen. Unfortunately, by the time a problem with a patient’s visual field is detectable by this method up to 40 per cent of the nerve fibres may already be damaged.
‘Glaucoma is a disease with a significant impact on people’s quality of life: it can affect everyday tasks such as driving, picking up objects and even recognising people they know. But it has to be at an advanced stage for people to realise they have a problem. We are hoping to catch it earlier with the new test, which will also give us a better idea of how people with glaucoma see the world and how best to support them in light of their vision loss.’
The new three-year project follows earlier research by Professor Loffler which similarly used a computer program to test face perception. The Caledonian Face
Test was established to promote early diagnosis of prosopagnosia or ‘face blindness’, a condition which makes it difficult, and sometimes impossible, for someone to recognise faces.