Are Smartphones Causing Esotropia?

Brianne N. Hobbs, OD


June 23, 2016

Acute Acquired Comitant Esotropia Related to Excessive Smartphone Use

Lee HS, Park SW, Heo H
BMC Ophthalmol. 2016;16:37

The world has more than 2 billion smartphone users.[1] In the United States, 67% of teens own a smartphone, and they spend an average of 6.5 hours per day looking at their smartphone or tablet screens.[2] These are shocking statistics.

Amidst fears of damage from the blue light emitted by smartphones, eye care providers have taken notice of the potential adverse effects on vision by widespread smartphone use. Most recently, another potential impact of smartphone use has been suggested: esotropia.

Study Summary

A group of South Korean researchers investigated adolescents who developed acute acquired comitant esotropia. This study was a retrospective chart review of all adolescents examined in the Pediatric Ophthalmology and Strabismus Service of Chonnam National University Hospital between January 2009 and June 2014.

Visual acuity of 20/20 in each eye and no photographic evidence of strabismus prior to the acute onset of esotropia were two of the inclusion criteria. Initial inclusion criteria were met by 19 patients, seven of whom had acquired esotropia of a known etiology. The remaining 12 patients had no etiologic explanation for the acquired esotropia and had normal neurologic testing and imaging. Each of these 12 patients was classified as an excessive smartphone user per patient history. The study defined excessive smartphone use as 4 or more hours of smartphone use daily for 4 consecutive months as reported by the patient and parents. These 12 patients used a smartphone for an average of 6 hours per day.

The average age of the 12 patients was 13.33 years and ranged from 7 to 16 years. Eight patients were myopic and four patients were mildly hyperopic. The average initial esotropia was 27.75 prism diopters (PD) at distance and did not differ significantly at near. Although it was unclear how this intervention was achieved because the study was retrospective, the patients experienced an average reduction in esotropia of 10 PD after refraining from smartphone use for 1 month.

Strabismus surgery was recommended for five patients who had large residual angles of esodeviation (>15 PD) after smartphone restriction, and three of those patients underwent bilateral medial rectus recessions.


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