Ophthalmology / Altruism / Motivation / Prospective studies / Humans / Glaucoma / Female / Male / Clinical Sciences / Aged / Middle Aged / Questionnaires / Optometry and Ophthalmology / Public health systems and services research / Patient Participation / Glaucoma / Female / Male / Clinical Sciences / Aged / Middle Aged / Questionnaires / Optometry and Ophthalmology / Public health systems and services research / Patient Participation