[1] Kings Coll London, Sect Acad Ophthalmol, Sch Life Course Sci, Fac Life Course Sci & Med FoLSM,St Thomas Hosp, Lambeth Palace Rd, London SE1 7EH, England
[2] Univ Groningen, Univ Med Ctr Groningen, Dept Ophthalmol, Hanzepl 1,Postbus 30-001, Groningen, Netherlands
[3] Univ Groningen, Univ Med Ctr Groningen, Dept Epidemiol, Hanzepl 1,Postbus 30-001, Groningen, Netherlands
[4] Kings Coll London, St Thomas Hosp, Dept Ophthalmol, Lambeth Palace Rd, London SE1 7EH, England
[5] Rijnstate Hosp, Dept Ophthalmol, Wagnerlaan 55,Postbus,9555, Arnhem, Netherlands