[1] Dongguk Univ, Dept Neurol, Grad Sch Med, Seoul, South Korea
[2] Dongguk Univ, Dept Opthalmol, Grad Sch Med, Seoul, South Korea
[3] Dongguk Univ, Dept Occipat & Environm Med, Grad Sch Med, Seoul, South Korea
[4] Hallym Univ, Dept Ophthalmol, Coll Med, Chunchon, South Korea
[5] Natl Canc Ctr, Dept Neurol, Singapore, Singapore