Analysis of the Pupillary Light Reflex Response Against Light Stimuli for Autism Screening in Children

Traditional diagnostic methods for autism spectrum disorder (ASD) predominantly rely on behavioral scales, which can be less effective among young children. This delay in diagnosis impedes timely interventions crucial for improving developmental outcomes. Pupillometry, which measures the pupillary light reflex (PLR), serves as a promising technique to address these challenges. It has the potential to provide biological insights into the central nervous system's functioning, indirectly revealing potential ASD risk.

This pilot proof-of-concept study assessed the PLR in 30 children aged 2-5, including 14 diagnosed with ASD (3 females) and 16 typically developing (TD) peers (10 females). The Modified Checklist for Autism in Toddlers (M-CHAT) and the Autism Diagnostic Observation Schedule-2 (ADOS-2) examinations complemented the PLR evaluations to confirm ASD diagnoses. Pupillary responses were recorded through 5 s video captures, emphasizing the measurement of contraction degree, latency, and time to maximum contraction.

Quantitative analysis demonstrated a significantly greater degree of pupillary constriction in ASD than TD children, while shorter latency and constriction time showed trend-level differences. An exploratory logistic regression model demonstrated promising in-sample discrimination between ASD and TD children (sensitivity 93%, specificity 86%, AUC 0.93); however, these estimates were obtained without external validation or cross-validation.

Pupillometry has the potential to become a method for early ASD detection. Its minimal requirement for child cooperation, low operational costs and ease of use, favors this technique as a tool for early screening and intervention in young children, particularly beneficial in resource-limited settings where traditional diagnostic facilities are scarce.