Association between near viewing and acute acquired esotropia in children during tablet and smartphone use

We investigated a possible association between the acute onset of esotropia and tablet or smartphone use in children. We characterized the clinical aspects of esotropia associated with tablet or smartphone use. The medical records of 10 children aged between 5 and 15 years old with presumably tablet or smartphone associated esotropia were reviewed regarding orthoptic examination and cycloplegic refraction. Legal guardians of the children were asked to fill in a questionnaire regarding tablet and smartphone use of their child. This questionnaire was also conducted in a control group of age-matched children. The results of this questionnaire were compared to search for possible determinants of tablet or smartphone associated esotropia. All 10 patients presented with a comitant esotropia ranging from 8 to 45 prism diopters with no significant difference between near and far. The mean age of onset was 9.8 years. Cycloplegic refraction showed a mild hyperopia in eight patients, a mild myopia in one patient and emmetropia in the other patient. All patients had near full refractive correction at the onset of esotropia. Diplopia was reduced after visual hygiene recommendations, however in six patients, strabismus surgery was needed. The working distance was significantly shorter in the 10 cases compared to the controls. In children with acute acquired esotropia, we found a statistically significant association with a smaller working distance during tablet or smartphone use compared to age-matched controls. We hypothesize that intensive near viewing can be a precipitating factor in this type of esotropia.