[1] Mem Univ Newfoundland, Dept Med, St Johns, NF, Canada
[2] Mem Univ Newfoundland, Dept Med Genet, St Johns, NF, Canada
[3] Mem Univ Newfoundland, Dept Ophthalmol, St Johns, NF, Canada
[4] Inst Ophthalmol, London, England
[5] Wills Eye Hosp, Philadelphia, PA USA