RT Journal Article SR Electronic T1 From reading books to increased smart device screen time JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 1 OP 2 DO 10.1136/bjophthalmol-2018-313295 VO 103 IS 1 A1 Mohamed Dirani A1 Jonathan G Crowston A1 Tien Y Wong YR 2019 UL http://bjo.bmj.com/content/103/1/1.abstract AB