Refractive Error Changes at Near After Smartphone Use

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Digital eye strain is prevalent among students using smartphones.
• Near work-induced transient myopia (NITM) is a temporary refractive shift associated with prolonged near tasks.
• The 20-20-20 paradigm (a 20-second break every 20 minutes for distance viewing) is a common recommendation to mitigate digital eye strain.

Purpose of the Study:

• To quantify short-timescale refractive recovery after smartphone use.
• To evaluate the effectiveness of distance viewing breaks, aligned with the 20-20-20 rule, for NITM recovery.
• To determine the optimal timing for refractive recovery during breaks.

Main Methods:

• A cross-sectional study involving 58 students with digital eye strain symptoms.
• Participants completed a 20-minute smartphone reading task.
• Objective refractive error was measured using an open-field autorefractor at baseline, immediately after the task, and after 20-second, 1-minute, and 2-minute distance viewing breaks.

Main Results:

• A myopic shift was observed immediately after the 20-minute smartphone task.
• Significant refractive recovery occurred within the first 20 seconds of distance viewing (P=0.007 for sphere, P=0.005 for SE).
• Further recovery showed diminishing returns between 20 seconds and 2 minutes, with cylinder measurements remaining stable.

Conclusions:

• The majority of refractive recovery following smartphone use happens within the initial 20 seconds of a distance viewing break.
• The findings support the refocusing principle of the 20-20-20 approach.
• More frequent, shorter breaks are effective for capturing accommodative/NITM recovery.