[1] Univ London London Sch Hyg & Trop Med, Dept Epidemiol & Populat Hlth, London WC1E 7HT, England
[2] Queens Univ Belfast, Dept Ophthalmol, Belfast, Antrim, North Ireland
[3] Univ E Anglia, Ctr Environm Risk, Norwich NR4 7TJ, Norfolk, England
[4] Acad Med Ctr, Netherlands Ophthalm Res Inst, Royal Netherlands Acad Arts & Sci, Amsterdam, Netherlands
[5] Acad Med Ctr, Dept Ophthalmol, Amsterdam, Netherlands
[6] Natl Inst Hlth Dev, Dept Epidemiol & Biostat, Tallinn, Estonia
[7] Haykeland Sykehus Univ Bergen, Bergen, Norway
[8] Univ Paris 12, Clin Ophthalmol, Paris, France
[9] Univ Verona, Clin Oculist, I-37100 Verona, Italy
[10] Aristotle Univ Thessaloniki, Dept Ophthalmol, GR-54006 Thessaloniki, Greece
[11] Erasmus MC, Dept Ophthalmol, Rotterdam, Netherlands
[12] Erasmus MC, Dept Epidemiol & Biostat, Rotterdam, Netherlands
[13] Univ Miguel Hernandez, Dipartimento Salud Publ, Alicante, Spain
[14] Queens Univ Belfast, Ctr Clin & Populat Sci, Belfast, Antrim, North Ireland