[1] Univ N Carolina, Cecil G Sheps Ctr Hlth Serv Res, Chapel Hill, NC 27599 USA
[2] Aravind Med Res Fdn, Madurai, Tamil Nadu, India
[3] NYU, Med Ctr, Dept Ophthalmol, New York, NY 10016 USA
[4] Johns Hopkins Univ, Sch Med, Dept Ophthalmol, Baltimore, MD 21218 USA
[5] Univ Maryland, Sch Med, Baltimore, MD 21201 USA
[6] Alcon Res Ltd, Ft Worth, TX USA
[7] Husson Coll, Dept Math Stat, Bangor, ME USA