PORTLAND, Ore. (KOIN) — A new study published by researchers at Washington State University suggests testing how the eye’s pupil changes in response to light could potentially be used to screen for autism in young children.
The proof-of-concept study was published in the journal Neurological Sciences in March and builds on previous research first author Georgina Lynch has done to study the development of a portable technology for screening.
A portable technology tool that could help with diagnoses could allow health care providers to catch children earlier in their development when interventions are more likely to benefit them.
“We know that when we intervene as early as ages 18 to 24 months, it has a long-term impact on their outcomes,” Lynch said. “Intervening during that critical window could be the difference between a child acquiring verbal speech and staying nonverbal. Yet, after 20 years of trying we still have not changed the average age of diagnosis here in the U.S., which is 4 years old.”
The study tested 36 children aged 6 to 17 who had been previously diagnosed with autism. It also tested a group of 24 typically developing children who served as controls.
The children’s pupillary light reflexes — or how their pupils changed in response to light — were tested by trained clinical workers using a handheld pupillometer device, which measures pupil dilation in response when it’s triggered by a visual stimulus.
Research studied the children’s test results and found that children with autism showed significant differences in the time it took for their pupils to constrict in response to light. Their pupils also took longer to return to their original size after light was removed.
“What we did with this study is we demonstrated the parameters of interest that matter — speed of constriction and return to baseline and we demonstrated it with monocular technology because we knew there is no significant difference between eyes in terms of the pupillary response in autism, unlike in head injury or concussion where it’s common to see unequal pupil sizes,” Lynch said.
In a previous study, Lynch tested children’s pupil response using binocular pupillometry in a laboratory setting. However, this method uses an expensive, stationary setup that measures both eyes at once.
Lynch is working on developing her own autism screening tool and the lower expense and portability associated with monocular technology made it possible to move testing into clinical settings, which is where Lynch hopes her future tool will be used.
Lynch said she first thought to use pupil dilation as a method to screen for autism when she was working as a clinician.
“I noticed this state in kids with ASD where their pupils were very dilated even in the presence of bright light,” she said, referring to autism spectrum disorder. “That system is modulated in the brain by cranial nerves rooted in the brainstem, and adjacent cranial nerves affect your ability to acquire speech and language. The pupillary light reflex tests the integrity of that system, so it seemed logical to try this very simple, noninvasive measure to determine whether there were differences between typical development and autism.”
For her next step, Lynch hopes to expand testing to a group of 300 or more 2- to 4-year-olds across a larger number of clinical sites.
The data from the next study will be used to attempt to validate her earlier findings and will be integrated into the screening device that will help providers decide if they need to refer a child for further evaluation.
In the meantime, Lynch is already preparing to file for Food and Drug Administration premarket approval for the screening device she’s been working on. She wants to get it from an academic research setting to use in pediatric clinics.
WSU said an estimated one in 44 children in the U.S. is diagnosed with autism spectrum disorder by age 8, but many kids get misdiagnosed or missed altogether due to the subjective nature of the diagnostic process.
Having a quick, objective screening method could help improve the accuracy and speed with which children are diagnosed.