Perform a near-vision visual acuity test on your mobile phone.
Several studies examining the effectiveness of mobile application technology in testing visual acuity are available for reference in the National Institute of Health’s U.S. National Library of Medicine (https://www.ncbi.nlm.nih.gov/pmc/?term=visual+acuity+near+vision+testing+iPhone+mobile+app).
If you have concerns about your vision health, consult your physician in addition to using this app, and before making medical decisions.