[1] Univ So Calif, Doheny Eye Inst, Keck Sch Med, Los Angeles, CA 90033 USA
[2] Univ So Calif, Dept Ophthalmol, Keck Sch Med, Los Angeles, CA 90033 USA
[3] Univ So Calif, Dept Prevent Med, Keck Sch Med, Los Angeles, CA 90033 USA
[4] Univ Wisconsin, Sch Med & Publ Hlth, Dept Ophthalmol & Visual Sci, Madison, WI USA