1. Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor , MI, USA
2. Leonard Davis School of Gerontology, University of Southern California, Los Angeles , CA, USA
3. Department of Population Health, Aga Khan University , Nairobi, Kenya
4. Department of Pathology, Aga Khan University , Nairobi, Kenya
5. Division of Geriatric Medicine, Ministry of Health , Nairobi, Kenya
6. Institute for Social Research, University of Michigan, Ann Arbor , MI, USA
7. Department of Internal Medicine, University of Michigan, Ann Arbor , MI, USA
8. Department of Economics, University of California, Berkeley , CA, USA
9. Center for Effective Global Action, University of California, Berkeley , CA, USA