[1] Univ Toronto, Fac Med, Dept Med, Toronto, ON, Canada
[2] Univ Toronto, Dept Ophthalmol & Vis Sci, Dept Med, Toronto, ON, Canada
[3] Univ Toronto, Dept Med, Div Neurol, Toronto, ON, Canada
[4] Kensington Vis & Res Ctr, Toronto, ON, Canada
[5] Kensington Vis & Res Ctr, 340 Coll St,Suite 501, Toronto, ON M5T 3A9, Canada