The rising prevalence of strabismus has been attributed in part to longer duration of near work and increased digital device use. Photo: Tamara Petrosyan, OD.

A hospital in China recently observed a rise in the number of patients presenting with acute acquired concomitant esotropia (AACE). This type of strabismus is uncommon among patients with concomitant esotropia and typically has a late age of onset and promising likelihood of binocular cooperation. However, findings from this study show that the condition’s prevalence is increasing in young adults, which the researchers suggest can be partially attributed to the use of electronic devices.

The research team leading this retrospective case-control study sought to investigate associated risk factors and clinical characteristics of patients with AACE to help determine the cause of the hospital’s increase in cases over the last five years. They included 62 patients with this form of strabismus who presented to the hospital and 73 orthotropic recruited volunteers as controls. The average age at onset for patients with AACE was 25. Three-quarters of those with the condition were myopic (75.8%), 14.5% were emmetropic and 9.7% were hypermetropic.

The researchers surveyed participants on time spent doing near work activities (defined as electronic device use, reading and precision instrument use) and using digital devices. The results showed that over half of AACE patients spent eight hours or more each day doing near work (56.5%), and 58.1% reported using devices late at night. Conversely, only 9.6% of patients in the control group reported eight hours or more of daily near work, and 16.4% participated in late-night digital device use. After comparing data from both groups, the team identified the following risk factors for AACE: long durations of near work activities and excessive late-night use of digital devices.

“Young adults were found to be the main group affected in the growing numbers of AACE in the last five years,” the researchers wrote. “Moreover, excessive close visual activities and immoderate late-night digital device use were found to be associated with AACE onset. Therefore, reductions in close visual activities, especially late-night use of digital devices, and high-quality spectacle prescriptions are recommended to prevent the onset of AACE,” they concluded.