Influence of presbyopia on smartphone usage among Chinese adults: a population study.

Importance Presbyopia, an essentially universal, age-related loss of the ability to focus un-aided on near objects, is the world's leading cause of visual impairment. Background Smartphone use is widespread in China, but little is known about the prevalence, determinants and correction of difficulties with smartphone use in the setting of presbyopia. Design Cross-sectional data from a population-based longitudinal cohort study. Participants A total of 1817 persons aged >= 35 years in Guangzhou, Southern China. Methods Participants underwent near visual acuity (NVA) testing and completed questionnaires on smartphone usage detailing knowledge of their own presbyopia status, frequency (hours/day) and subjective difficulties with use of mobile and smartphones. Presbyopia was defined as uncorrected bilateral NVA <= 6/12 with best-corrected bilateral NVA >6/12. Main Outcome Measures Difficulty in smartphone use associated with uncorrected presbyopia. Results Among 1427 respondents (78.5%) undergoing examination, 1191 (83.5%) completed questionnaires (mean age 52.3 +/- 11.6 years; 54.9% women). Among 451 persons (37.8%) with presbyopia owning smartphones, 290 (64.3%) reported difficulty using them. Multiple ordinal logistic regression modelling showed difficulty in smartphone use due to presbyopia was associated with higher educational level (P = .013), worse NVA (P < .001) and more time spent using smartphones (P = .002 for 1-3 hours/day). Among persons with presbyopia owning smartphones, 353 (78.0%) said they would pay >US$15 (median US$45) for innovations making smartphone use easier. Conclusions and Relevance Difficulty in using smartphones in the presence of presbyopia is common and affected persons are willing to pay for useful solutions to the problem.