Siamak Sabour1,2, Fariba Ghassemi3. 1. Department of Clinical Epidemiology, Shahid Beheshti University of Medical Sciences, Tehran 198353-5511, Iran. 2. Safety Promotion and Injury Prevention Research Center, Shahid Beheshti University of Medical Sciences, Tehran 198353-5511, Iran. 3. Department of Retina and Vitreous Diseases, Ocular Oncology, Farabi Eye Hospital, Faculty of Medicine, Tehran University of Medical Sciences, Tehran 1416753955, Iran.