[1] Case Western Reserve Univ, Epidemiol & Biostat, Cleveland, OH 44106 USA
[2] Harvard Med Sch, Massachusetts Eye & Ear Infirm, Dept Ophthalmol, Boston, MA USA
[3] Brigham & Women, Channing Div Network Med, Boston, MA USA
[4] Duke Univ, Med Ctr, Dept Ophthalmol, Durham, NC 27710 USA
[5] Duke Univ, Med Ctr, Dept Med, Durham, NC 27710 USA
[6] Univ Calif San Diego, Hamilton Eye Ctr, Dept Ophthalmol, San Diego, CA 92103 USA