1. From the Departments of Pediatrics,
2. Ophthalmology, and
3. Central Microscopy Research Facility, University of Iowa, Iowa City, Iowa; and
4. Statistics and Actuarial Science and the
5. Ophthalmology, and5The Howard Hughes Medical Institute, Iowa City, Iowa.
6. From the Departments of Pediatrics,5The Howard Hughes Medical Institute, Iowa City, Iowa.