Testing children’s eyes is tricky at the best of times, but with non-verbal pre-schoolers it is almost impossible.
“Specialists agree early intervention gives the best chance of a good outcome in the treatment of amblyopia,” says Dr Jason Turuwhenua, a research fellow at the School of Optometry and Vision Science at the University of Auckland. “But young children don’t respond well to eye charts as they’re not familiar with the letters, and it requires a subjective response they aren’t able to give yet.”
Dr Turuwhenua is an engineer who became interested in the application of engineering methods in resolving vision problems. Along with vision scientist Dr Ben Thompson they began working on creating a system to accurately test the sight of young children. In October 2015 they were awarded almost a million dollars in funding from the Ministry of Business Innovation and Employment.
“Our system, which can be used for children as young as two years, uses optokinetic reflex, an involuntary motion of the eye that occurs when watching a moving scene or pattern,” explains Dr Turuwhenua. “In our system we envisage that a child would watch a screen and we measure their eye movements – if they display the reflex they would pass, and if they don’t display the reflex then it would be indicative of a problem that requires further investigation.”
The work dovetails with research from Professor Steven Dakin’s group in the same school, who have worked with adults to show that the optokinetic reflex mirrors people’s subjective experience of motion.
“Our findings show that eye-movement based tests of acuity and contrast-sensitivity are valid substitutes for tests relying on the patients’ own response.” says Professor Dakin whose work will appear later this year in the journal Scientific Reports.
Dr Turuwhenua notes that these tests could be used to measure refractive error and his team are also looking at the potential to develop an app. They are aiming to have the test available to use in a clinical setting within two years.
