1. Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
2. Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
3. Department of Medical Surgical Nursing, Shahid Beheshti University of Medical Sciences, Tehran, Iran
4. Clinical Research Development Unit, Imam Hossein Hospital, Shahroud University of Medical Sciences, Shahroud, Iran
5. Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran