Smartphone Near-Viewing Demands Differ in Corrected Presbyopes: Implication for Presbyopic Correction.

OBJECTIVE: This study aimed to investigate near viewing modifications during smartphone usage between presbyopes and non-presbyopes. METHODS: A cross-sectional study design was employed, involving corrected presbyopes and non-presbyopes who completed a series of standardised reading tasks on a smartphone under habitual viewing conditions. The time taken to complete each reading task was recorded. Viewing distance and craniovertebral angle were measured from images captured at a distance of 2 metres while participants performed the tasks, allowing for objective assessment of posture and working distance. RESULTS: Corrected presbyopes used significantly larger font sizes to complete the reading tasks compared with non-presbyopes (p < 0.01). They also completed the reading tasks at significantly greater viewing distances (p < 0.001) and required significantly longer completion times (p < 0.001). However, craniovertebral angles did not differ significantly between the two groups during task performance (p > 0.05), suggesting similar neck posture despite differences in visual demand. CONCLUSION: Despite reading with a significantly larger font size, presbyopes required a longer viewing distance and more time to complete all reading tasks, indicating increased visual effort and adaptation during smartphone use. These findings highlight the additional visual demands experienced by corrected presbyopes during near digital tasks. Therefore, prescribers should consider the specific visual tasks an individual engages in when prescribing presbyopic correction rather than relying solely on the conventional 40 cm near working distance, as real-world smartphone usage may require different accommodative and ergonomic considerations.