Dynamic and Static Pupil Changes After Near Work: Comparison Between Reading a Book and Using a Smartphone

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Accommodation-induced decreases in static pupil size are well-documented.
• The impact of near-work activities on dynamic pupillary responses remains less understood.

Purpose of the Study:

• To investigate and compare the effects of reading a book versus using a smartphone on both static and dynamic pupil parameters.
• To elucidate how different near-work activities influence pupillary behavior.

Main Methods:

• Seventy-six healthy young adults with significant daily near-work exposure (>4 hours) participated.
• Participants were categorized into two groups: book readers (Group 1) and smartphone users (Group 2).
• Pupil dynamics and static parameters were assessed before and after a 1-hour continuous near-work session.

Main Results:

• Near work significantly reduced pupil diameter (PD) in all static measures.
• Smartphone use led to significant changes in all dynamic pupil parameters.
• Book reading resulted in significant changes in initial diameter, contraction amplitude and velocity, and dilation duration, with initial diameter changes being more pronounced than in the smartphone group.

Conclusions:

• Both reading books and using smartphones alter pupil dynamics, characterized by reduced diameter and velocity, and increased latency.
• The specific type of near-work activity influences the pattern and magnitude of these pupillary changes.