1. From the Retina Foundation of the Southwest, Dallas, Texas;
2. From the Retina Foundation of the Southwest, Dallas, Texas; the 2Department of Ophthalmology, University of Texas Southwestern Medical School, Dallas, Texas; and
3. the Department of Ophthalmology, University of Texas Southwestern Medical School, Dallas, Texas; and
4. the College of Optometry, University of Houston, Houston, Texas.