Diagnosis of autism linked to light response in infants

Babies whose pupils react more strongly to sudden changes in light intensity are more likely to later be diagnosed with autism spectrum disorder (ASD), a study has shown.

Researchers from Birkbeck, University of London, said their findings provide support for the view that sensory processing plays an important role in the development of the disorder.

The study, published in the journal Nature Communications, saw them investigate the pupillary light reflex – a basic mechanism controlling the amount of light that reaches the retina in which the pupil contracts when the eye is exposed to increases in brightness.

The participants, from the UK and Sweden, were 10 months old when their pupillary responses to light were first examined with an eye-tracker which measured these changes in pupil size.

They were followed until they were three years of age, at which point they took part in a diagnostic evaluation.

Those infants who eventually fulfilled criteria for ASD showed a stronger pupillary response than infants who did not later fulfil ASD criteria.

Dr Teodora Gliga, research fellow at Birkbeck’s Centre for Brain and Cognitive Development, who led the UK branch of the study, said: “For a long time, autism has been defined by atypical social interaction and communication.

“However, researchers are increasingly embracing the view that the earliest signs of the condition may lie in more basic processes of brain development.

“Understanding the developmental mechanisms behind autism will help improve early detection as well as the design of early interventions.”