Author Contributions: Dr Friedman 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: Ko, Vitale, Cotch, Saaddine, Friedman.
Acquisition of data: Ko, Chou, Saaddine, Friedman.
Analysis and interpretation of data: Ko, Vitale, Cotch, Friedman.
Drafting of the manuscript: Ko, Vitale, Friedman.
Critical revision of the manuscript for important intellectual content: Ko, Vitale, Chou, Cotch, Saaddine, Friedman.
Statistical analysis: Ko, Vitale, Friedman.
Administrative, technical, or material support: Chou, Cotch.
Study supervision: Saaddine, Friedman.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Friedman reports having consulted for Alcon, Bausch and Lomb, Merck, Pfizer, Allergan, Nidek, and QLT. Dr Ko reports receipt of support for travel to meetings for the study or other purposes from the National Eye Institute (ARVO travel grant), a Pepose travel grant, and a David Friedman Research Grant Award for provision of writing assistance, medicines, equipment, or administratrive support. The remaining authors report no disclosures.
Funding/Support: This study was supported by the Centers for Disease Control and Prevention (CDC) grant 1U58DP002653-01 and the David Friedman Research Grant Award. The National Health and Nutrition Examination Survey (NHANES) is sponsored by the National Center for Health Statistics (NCHS), CDC. Funding for the vision component was provided by the National Eye Institute (NEI), National Institutes of Health (NIH), Intramural Research Program grant Z01EY000402.
Role of the Sponsor: The CDC provided funding support in preparation, review, and approval of this article before submission. Dr Friedman was the principal investigator who provided funding support, was involved in the analysis and interpretation of the data, and was involved in preparation, review, and approval of this article before submission. The NCHS was involved in the design and conduct of the study and in data collection. The NEI provided funding and support for the vision examination and was involved in the design and conduct of the vision component of data collection.
Disclaimer: The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the NIH or the CDC.
Additional Contributions: We are grateful to all the individuals who agreed to participate in NHANES, without whose time and dedication this study would not have been possible.