[1] Childrens Hosp Philadelphia, Scheie Eye Inst, Div Neuroophthalmol, Dept Neurol, Philadelphia, PA 19104 USA
[2] Childrens Hosp Philadelphia, Scheie Eye Inst, Dept Ophthalmol, Philadelphia, PA 19104 USA
[3] Univ Penn, Sch Med, Hosp Univ Penn, Philadelphia, PA 19104 USA