[1] Johns Hopkins Univ, Sch Med, Wilmer Inst, Zanvyl Krieger Childrens Eye Ctr, Baltimore, MD 21205 USA
[2] UCLA Fielding Sch Publ Hlth, Dept Biostat, Los Angeles, CA USA
[3] Jules Stein Eye Inst, Los Angeles, CA USA
[4] Univ Calif Los Angeles, Dept Ophthalmol, Los Angeles, CA USA
[5] UCLA Fielding Sch Publ Hlth, Dept Epidemiol, Los Angeles, CA USA
[6] Amer Acad Ophthalmol, Hoskins Ctr, San Francisco, CA USA