1 Pediatric Neurology Unit, Department of Pediatrics, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
2 Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
3 Pediatric Neurology Unit, Department of Pediatrics, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India. drnsankhyan@yahoo.co.in.