1. UM Eye Research Centre, Department of Ophthalmology, Universiti Malaya, Jalan Profesor Diraja Ungku Aziz, Kuala Lumpur, Malaysia.
2. Division of Neurology, Department of Medicine, Universiti Malaya, Jalan Profesor Diraja Ungku Aziz, Kuala Lumpur, Malaysia.
3. Department of Social and Preventive Medicine, Faculty of Medicine, Universiti Malaya, Jalan Profesor Diraja Ungku Aziz, Kuala Lumpur, Malaysia.