Excessive Smartphone Use and Myopia in Teens
By Lynda Seminara
Selected by Stephen D. McLeod, MD
Journal Highlights
Ophthalmology, December 2021
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How much of a relationship is there between smartphone use and myopia prevalence? Enthoven et al. studied the use of smartphones among teenagers and found that refractive errors were more common when smartphone sessions lasted 20 minutes or longer, particularly for those teens who spent less time outdoors.
For this cross-sectional study, teens (12-16 years) were recruited from six Dutch secondary schools and from the Generation R study. A myopia app was installed on their phones; the app calculated phone time in hours per day and face-to-screen distance for a five-week period. On-screen episodes lasting 20 minutes without a break were documented and were deemed “continuous use.” Twice weekly, the app prompted participants to log the time they had spent outdoors. Ocular biometry was performed, and cycloplegic refractive error was measured. Linear mixed models were applied, with overall smartphone use, continuous use, and face-to-screen distance as determinants, and spherical equivalent of refraction (SER) and the ratio of axial length to corneal radius (AL:CR) as outcome measures. Findings were stratified by the level of outdoor exposure.
Valid smartphone data and eye measurements were available for 272 enrollees (average age, 13.7 years). The overall myopia prevalence was 18.9%. On school days, mean daily smartphone use (± standard deviation) was 3.71 ± 1.70 hours. The association with AL:CR was minimally significant, but the association with SER was not. The mean number of continuous-use sessions (20 minutes without a break) per day was 6.42 ± 4.36, which correlated significantly with SER and AL:CR. When stratified by time spent outdoors, continuous use was significant for those teens with low outdoor exposure. Face-to-screen distance and smartphone use on weekends had no significant relationship to SER or AL:CR.
The findings suggest that the teens in this study spend nearly four hours a day on their smartphones and that uninterrupted 20-minute sessions increase the risk of myopia.
The original article can be found here.