[1] Harvard Med Sch, Dept Ophthalmol, Massachusetts Eye & Ear, Boston, MA USA
[2] UCL, Great Ormond St Inst Child Hlth, Dept Populat Policy & Practice Res, London, England
[3] Univ Adelaide, Adelaide Med Sch, Discipline Ophthalmol & Visual Sci, Adelaide, Australia
[4] Govt Med Coll & Hosp, Dept Ophthalmol, Chandigarh, India
[5] Univ Pittsburgh, Vis Inst, Dept Ophthalmol, Sch Med, Pittsburgh, PA USA
[6] Univ Pittsburgh, Vis Inst, Sch Med, Pittsburgh, PA 15213 USA