[1] Linkoping Univ Hosp, Neurol, Linkoping, Sweden
[2] Sun Yat Sen Univ, State Key Lab Ophthalmol, Guangzhou, Peoples R China
[3] Linkoping Univ Hosp, Neurophysiol, Linkoping, Sweden
[4] Karolinska Inst, Neurol, Stockholm, Sweden
[5] Linkoping Univ Hosp, Ophthalmol, Linkoping, Sweden