Impact of prolonged digital device use on acquired comitant esotropia: ACE-DD study 2

To investigate changes in strabismus angles in children and young adult patients with recent onset of constant acquired comitant esotropia (ACE) following instructions on hand-held digital devices (DD).

Prospective multicenter non-randomized interventional study.

This study included subjects aged 5-35 years who developed ACE within 1 year. Subjects were divided into two groups: (i) subjects who used DD for an average of ≥120 minutes/day for junior high-school students and older and ≥60 minutes/day for primary-school students and younger (DD+); and (ii) subjects who used DD for less than that (DD-) based on the questionnaire at the study's start. During the initial visit, glasses were prescribed when necessary; verbal instructions on DD use including time reduction and viewing-distance elongation were provided. For each group, strabismus angles at the initial visit and at 3 months were compared. Cure was defined as esophoria within 8 prism diopters without symptoms.

In total, 181 cases were investigated. At baseline, strabismus angles in DD+ and DD- groups were 23±14 PD and 25±15 PD at near and 25±13 PD and 27±14 PD at distance, respectively. At 3 months, they were 22±16 PD and 25±15 PD at near and 23±14 PD and 27±13 PD at distance, respectively. Only in the DD+ group, reduction in strabismus angle was observed, but this was not clinically significant. Ten and 1 subjects in DD+ and DD- groups were cured.

Although changes in strabismus angles were not large enough, DD use instructions were beneficial for some ACE subjects.