Impact of digital device usage on binocular vision and refractive status

Abstract

The rapid integration of digital devices into everyday life has significantly increased visual demands among teenagers, leading to growing concerns regarding ocular health. Prolonged near work on smartphones, tablets, and computers may result in digital eye strain, early refractive changes, and disturbances in binocular vision functions due to stress on accommodative and vergence mechanisms. The present study aimed to evaluate the impact of prolonged digital device usage on binocular single vision parameters and refractive status among teenagers by comparing high users (≥4 hours/day) and low users (<4 hours/day). An observational study was conducted among 201 emmetropic participants aged 13 to 19 years who had been using digital devices for at least six months. A comprehensive ocular assessment was performed which included measurement of near point of accommodation, accommodative facility, positive and negative relative accommodation, near point of convergence, fusional vergence ranges, stereopsis, and refractive status. In addition, a structured questionnaire was administered to document subjective visual symptoms associated with digital device use. The findings revealed that high digital device users demonstrated significantly reduced accommodative amplitude, decreased accommodative facility, lower positive fusional vergence, and a receded near point of convergence when compared with low users (p<0.05). Participants with higher screen exposure also reported a greater frequency of symptoms such as headaches, blurred near vision, and visual fatigue. Furthermore, subtle subclinical myopic shifts were observed among high users, suggesting a possible association between prolonged near work and early refractive instability. The study indicates that excessive screen time among teenagers may adversely affect binocular single vision efficiency and increase the risk of visual discomfort and early refractive changes. Preventive strategies including regular breaks during screen use, increased outdoor activities, proper ergonomic viewing conditions, and periodic eye examinations are recommended to maintain ocular health in the digital era