1. Department of Optometry, Mashhad University of Medical Sciences, Mashhad,
2. Epidemiology and Biostatistics Department, School of Public Health, Tehran University of Medical Sciences,
3. Farabi Eye Hospital, Tehran University of Medical Sciences,
4. Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran,
5. Optometry Unit, Dastgheib Hospital, Shiraz University of Medical Sciences, Shiraz,
6. Khatamanbia Eye Hospital, Mashhad University of Medical Sciences, Mashhad, and
7. Emam Khomaini Hospital, Mashhad University of Medical Sciences, Fariman, Iran