A longitudinal study of pupillary light reflex in 6- to 24-month children

Clare Kercher,Gang Yao,Leila Azinfar,Judith H Miles,Dinalankara M R Dinalankara,T Nicole Takahashi

doi:10.1038/s41598-020-58254-6

Abstract

Pupillary light reflex (PLR) is an involuntary response where the pupil size changes with luminance. Studies have shown that PLR response was altered in children with autism spectrum disorders (ASDs) and other neurological disorders. However, PLR in infants and toddlers is still understudied. We conducted a longitudinal study to investigate PLR in children of 6–24 months using a remote pupillography device. The participants are categorized into two groups. The ‘high risk’ (HR) group includes children with one or more siblings diagnosed with ASDs; whereas the ‘low risk’ (LR) group includes children without an ASD diagnosis in the family history. The participants’ PLR was measured every six months until the age of 24 months. The results indicated a significant age effect in multiple PLR parameters including resting pupil radius, minimal pupil radius, relative constriction, latency, and response time. In addition, the HR group had a significantly larger resting and minimal pupil size than the LR group. The experimental data acquired in this study revealed not only general age-related PLR changes in infants and toddlers, but also different PLRs in children with a higher risk of ASD.

Highlights

Pupillary light reflex (PLR) is an involuntary response where the pupil size changes with luminance
Pupillary light reflex (PLR) is the involuntary and nearly instantaneous pupil size change that occurs as a response to the luminous intensity of light that falls on the retina
The PLR’s potential for early identification of risk of autism was recently demonstrated by Nyström et al.[16]. They reported that the pupil constricted more in 9- to 10-month old infants who later received an autism spectrum disorders (ASDs) diagnosis and the amount of PLR constriction was correlated with the severity of ASD symptoms

Summary

Introduction

Pupillary light reflex (PLR) is an involuntary response where the pupil size changes with luminance. The PLR’s potential for early identification of risk of autism was recently demonstrated by Nyström et al.[16] They reported that the pupil constricted more in 9- to 10-month old infants who later received an ASD diagnosis and the amount of PLR constriction was correlated with the severity of ASD symptoms. PLR latency (the delay between stimulation onset and the beginning of pupil constriction) decreased from 6 to 8 years in children of typical development; this trend was not apparent in age-matched children with ASD11, suggesting that the PLR differences between individuals with and without ASD may change with age. Exiting experimental evidence[12] suggested that different age trends may explain apparent inconsistencies in ASD associated atypical resting pupil sizes reported in the literature[24,25,26]

Methods

Results

Conclusion