Could a simple eye test diagnose autism? Pupils of children with the condition 'take markedly longer to narrow after penlight test'

  • Penlight reflex test involves a doctor shining a light in a patient's eye
  • It causes the pupil to dilate or become larger and wider, as it adapts
  • Scientists tested pupil reflex of 24 children aged 10 to 17 years old
  • Found in 70% of those with autism their pupils took markedly longer to constrict, or narrow, back to their normal state
  • Raises hopes of a cheaper and faster diagnostic test for the condition 

By Lizzie Parry For Dailymail.com

Published: 15:37 EST, 15 October 2015 | Updated: 19:06 EST, 15 October 2015

A simple pupil reflex test, using a penlight, could help doctors diagnose autism, experts say

A simple pupil reflex test, using a penlight, could help doctors diagnose autism, experts say

A simple eye test could one day diagnose autism, a study has suggested.

The penlight reflex test, similar to that already performed by doctors, has shown promising results in preliminary tests by scientists.

The team, at Washington State University, believe the inexpensive test could lead to quicker diagnosis of children with the condition, as well as faster access to treatment.

Data from their pilot study is so encouraging, the researchers plan to conduct further testing in a larger pool of children in clinical settings, not just a laboratory.

Lead investigator Dr Georgina Lynch, assistant clinical professor of speech-language pathology, said: 'Our results suggest that an inexpensive, noninvasive pupil penlight reflex test could be a physiological measurement of autism.'

The study's findings add weight to a growing body of evidence showing that the pupils of children with autism constrict more slowly to flashes of light than pupils of their peers without the condition.

But Dr Lynch's research takes the theory a step further.

Hers is the first study to examine whether social deficits seen in the disorder are linked to a sort of misfiring that occurs in the optic and oculomotor nerves, located in the brainstem.

She said an abnormality there could help explain why people with autism have difficulty making eye contact, and are often sensitive to bright lights. 

'Deficient functioning of these two cranial nerves makes it challenging for a child to maintain eye gaze,' she explained.

'This is necessary for developing joint attention and for paying attention to dynamic features of a person's face.

'These fundamental physical behaviours are needed to develop language and socialisation.' 

Dr Lynch said her findings suggest the penlight pupil reflex test appears to give scientists a 'window' into the neural functioning of the brainstem, and its effect on the child's behaviour. 

If validated by larger studies, the straightforward, cheap test may, in the future, be used as a way to use more objective diagnoses of autism.

Dr Lynch said this would remove the need to 'rely solely on behavioural assessments, which can be subjective and can't definitively diagnose the disorder before a child is two or three years old'.

She added that many children do not display all the features of autism until then, or in some cases the features get missed so the diagnosis is made much later.

To arrive at their findings, Dr Lynch and her team tested 24 young people, aged 10 to 17.

Lead investigator at Washington State University, Dr Georgina Lynch, pictured left, hopes the test, demonstrated, will offer a quicker alternative to current tests, and allow children access to treatment faster

Lead investigator at Washington State University, Dr Georgina Lynch, pictured left, hopes the test, demonstrated, will offer a quicker alternative to current tests, and allow children access to treatment faster

Half had already been diagnosed with high-functioning autism, the other half did not have the condition.

Pupil reflexes were measured in response to light in each eye for four seconds for four trials. 

The pupils of children in the group with autism took markedly longer to constrict in 70 per cent of cases, Dr Lynch revealed. 

The next step is to see if the result is confirmed in a larger group of children, including those younger than 10.

Clinical trials in desginated doctors' surgeries and clinics are expected to begin next year.

Dr Lynch concluded: 'If a simple technology can be used by paediatricians to spot a likely sign of autism during routine exams, then we can get these kids a quicker diagnosis and quicker treatment.

'The sooner we can intervene with proven techniques, the better their chances in the world.'

Dr Lynch presented her findings at the International Society for Autism Research in Salt Lake City earlier this year.  

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