1. King Khaled Eye Specialist Hospital, Al-Oruba Street, P.O. Box 7191, Riyadh 11462, Saudi Arabia
2. The Eye Center and the Eye Foundation for Research in Ophthalmology, Riyadh, Saudi Arabia
3. Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
4. The Wilmer Ophthalmological Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA