1 Scheie Eye Institute (H-N.Y.), Perelman School of Medicine at the University of Pennsylvania; Philadelphia, Pennsylvania, USA.
2 Department of Ophthalmology (I.O.), Boston Children's Hospital, Boston, Massachusetts, USA; Department of Population Medicine (I.O.), Harvard Medical School; Boston, Massachusetts, USA; Department of Social and Behavioral Sciences (I.O.), Harvard School of Public Health; Boston, Massachusetts, USA.
3 Division of Ophthalmology (J.T.O.), Children's Hospital of Philadelphia; Philadelphia, Pennsylvania, USA. Electronic address: oattsj2@chop.edu.