Author Contributions: Dr B. Klein had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: B. Klein, Lee.
Acquisition of data: R. Klein, Lee.
Analysis and interpretation of data: R. Klein, Lee, Grady.
Drafting of the manuscript: B. Klein, Lee.
Critical revision of the manuscript for important intellectual content: R. Klein, Lee, Grady.
Statistical analysis: Lee.
Obtained funding: B. Klein, R. Klein.
Administrative, technical, or material support: B. Klein, Grady.
Study supervision: B. Klein.
Financial Disclosures: None reported.
Funding/Support: The National Eye Institute grant EY06594 provided funding for the entire study; Research to Prevent Blindness, New York, NY, provided further additional support for data analyses.
Role of the Sponsors: The study funders had no role in the design and conduct of the study, in the collection, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.