Author Contributions: Drs M. Azam, Collin, and den Hollander had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Financial Disclosure: None reported.
Funding/Support: This work was supported by grant 530 from the Higher Education Commission of Pakistan (Dr Qamar), in part by a core grant from Shifa College of Medicine, and by grant BR-GE-0507-0381-RAD from the Foundation Fighting Blindness (Dr den Hollander). The Higher Education Commission of Pakistan awarded an International Research Support Initiative Program Scholarship to Dr M. Azam to perform part of the research at the Radboud University Nijmegen Medical Centre. Mr Khan was supported by the Stichting Nederlands Oogheelkundig Onderzoek, Dr Arimadyo was supported by the Stichting Nelly Reef Fund, and Dr Cremers was supported by the Stichting ter Verbetering van het Lot der Blinden.
Additional Contributions: We thank the families who participated in this study.