The research findings reveal children with Down syndrome align the eyes well but fail to focus correctly on a near object.
The 3 year study was with 41 participants with Down syndrome aged 6-16 years whom in the majority (75%) had problems focusing. This was compared with 76 typically developing children. It is the first time such a study has been carried out specifically on children with Down syndrome.
Ulster University researchers used sophisticated techniques to study how the children moved their eyes and viewed objects while looking at an animated movie. They evaluated all three aspects of near vision simultaneously including eye movements, pupils and focusing.
Ulster University's Dr Julie-Anne Little said: "Down syndrome is the most common cause of intellectual impairment. Children with Down syndrome are known to be visual learners but from an early age they can have vision problems. It is therefore important that their visual needs are met in order to maximise their educational development and quality of life. Until now the precise cause of poor near vision in children with Down syndrome has remained unidentified.
"Our research clearly found that children with Down syndrome try to see but fail to focus. Future research should now explore the possibility of a neurological or muscular anomaly in optics of the Down syndrome eye. This promises great potential in leading to a breakthrough in better vision solutions for the hundreds of thousands of people in the world who have Down syndrome."