Objective Monitoring of Tablet Use-Related Optical Exposure and Its Association With Axial Length in Preschool...

Area of Science:

• Pediatric Ophthalmology
• Environmental Health
• Digital Health

Background:

• Rising global myopia prevalence in children necessitates research into early-life visual development.
• Preschool years are critical for visual development, with increasing screen time raising concerns.
• The impact of screen brightness and ambient light on myopia risk in preschoolers remains under-investigated.

Purpose of the Study:

• To investigate the association between screen brightness, ambient illuminance, and axial length in preschool children.
• To provide evidence for screen brightness recommendations for young children.
• To inform guidelines for safe digital device use in early childhood.

Main Methods:

• A cross-sectional monitoring study in Shanghai, China (March-July 2023) involving 199 preschool children (3-6 years).
• Objective, real-time data collection on screen time and brightness via tablet software over 7 days.
• Standardized ophthalmic assessments, ambient illuminance measurements, and parental questionnaires were utilized.

Main Results:

• Higher ambient illuminance during tablet use was significantly inversely associated with axial length (P=.006).
• A nonlinear relationship between screen brightness and axial length was found (Pnonlinearity=.004), with elongation accelerating above ~27 cd/m².
• Male sex was significantly associated with longer axial length (P<.001).

Conclusions:

• Increased ambient illuminance during screen use is associated with shorter axial length in preschoolers.
• Screen brightness has a nonlinear impact on axial elongation, highlighting the importance of optimal device settings.
• Findings support guidelines for safe digital device use and appropriate ambient lighting for young children's visual health.