CHANGES IN ACCOMMODATIVE FUNCTION OF YOUNG ADULTS IN THEIR TWENTIES FOLLOWING SMARTPHONE USE

The present study was conducted to investigate whether near work with smartphone could induce thechange of accommodative function. Methods: Total 63 subjects(26 male and 37 female) in their 20s were firstlyexamined their visual functions related to accommodation and uncorrected spherical equivalent power as thecontrol. After that, the subjects were asked to read a book for 30 min and sequentially watch a movie onsmartphone for the same time after 30 min-break under the indoor light or as it was in the reverse order to avoidtime-ordered effect. Their accommodative functions, 1) accommodative amplitude, 2) accommodative facility, 3)relative positive/negative accommodation, and 4) accommodative lag and their uncorrected spherical equivalentpower were examined again following each task and compared with the control values. Results: The monocularaccommodative amplitude was significantly decreased after smartphone watching compared with it after reading.
The monocular and binocular accommodative facilities were tended to reduce after smartphone watching andbook reading but were not significantly different. Neither significant change in positive relative accommodationwas determined after smartphone watching nor book reading. Negative relative accommodation after smartphonewatching was almost unchanged unlike reading a book. The accommodative lag after smartphone work wassignificantly higher than after book reading. Conclusions: The near work with a smartphone for 30 min inducedthe change of some accommodative functions, which was significantly greater than when reading under the sameworking environment.