1. Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
2. Drexel University College of Medicine, Philadelphia, PA 19129, USA
3. Department of Ophthalmology, King Hussein Medical Center Royal Medical Services, Amman 11180, Jordan
4. Department of Ophthalmology, Veteran Affairs North Texas Health Care System Medical Center, Dallas, TX 75216, USA