Viewing distance, font size and symptoms of eyestrain in non‐presbyopic and presbyopic smartphone users. - Naipal, Shivani; Khumalo, Nqobile; Rahmtoola, Muhammad; Chagi, Sinoxolo; Didi, Luyanda; Mthethwa, Sandile; Ndhlovu, Simmy; Persadh, Bhavna; Rampersad, Nishanee (Ophthalmic & Physiological Optics, 2025)