Measuring how the eyes respond to light could one day be used to screen for autism in young children, according to a recent US study.
The proof-of-concept study builds on earlier work to support the development of a portable technology that quickly and easily screens for autism – a condition that effects 1 in 44 US children.
The tool would enable healthcare providers to diagnose children earlier when interventions are more likely to help them.
The study was led by Georgina Lynch, an assistant professor in the Washington State University Elson S. Floyd College of Medicine.
Lynch worked with children with autism while practicing as a speech-language pathologist.
The researcher said:
“We know that when we intervene as early as ages 18 to 24 months it has a long-term impact on their outcomes.
“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 four years old.”
The study tested 36 aged between six and 17 who had previously been diagnosed with autism.
A group of 24 typically-developing children served as controls.
The children’s pupillary light reflexes were tested using a handheld pupillometer device.
The analysis revealed that the children with autism showed significant differences in the time it took for their pupils to constrict in response to light.
It also took longer for their pupils to return to their normal size after the light was removed.
Lynch said:
“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.”
A previous study led by Lynch tested children in a lab setting using binocular pupillometry, which uses an expensive, stationary setup that measures both eyes at once rather than individually in the new study.
The lower cost and increased portability associated with monocular technology made it possible to move testing into clinical settings similar to those in which the screening tool Lynch is developing might be used once it is commercially available.
Lynch is now working to expand testing to a group of 300 or more two-to-four-year-olds across a greater number of clinical sites.
Data from that study will be used to validate the earlier findings and support the development of the ultimate screening device to provide a benchmark for providers to use when deciding whether or not to refer a child for evaluation.
Lynch is also preparing to file for FDA premarket approval for the screening device through spinoff company Appiture Biotechnologies.
Lynch cofounded the company to help move the technology from an academic research setting towards widespread use in paediatric clinics.
Lynch’s interest in this area grew from her experiences watching parents struggle through the cumbersome process of pursuing a formal diagnosis for their child.
The researcher said:
“Even as a clinician, I noticed this state in kids with ASD where their pupils were very dilated even in the presence of bright light.
“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, non-invasive measure to determine whether there were differences between typical development and autism.”
Image by Cori Kogan, Washington State University
