1. From the Department of Community Medicine, Avon Longitudinal Study of Parents and Children, University of Bristol, Bristol, United Kingdom; the
2. From the Department of Community Medicine, Avon Longitudinal Study of Parents and Children, University of Bristol, Bristol, United Kingdom; the2Bristol Eye Hospital, Bristol, United Kingdom; and the
3. From the Department of Community Medicine, Avon Longitudinal Study of Parents and Children, University of Bristol, Bristol, United Kingdom; the3Jacobs Foundation, Zurich, Switzerland.