Clin Assoc Prof Ong Thun How is a Senior Consultant with the Dept of Respiratory & Critical Care Medicine. She is also the immediate past Director, Sleep Disorder Unit (SDU), under her lead the SGH Sleep Disorder Unit was the first adult sleep unit in Singapore to achieve international accreditation by The Thoracic Society of Australia and New Zealand.

Clin Assoc Prof Ong led the unit to a successful re-accreditation and she played a significant rolde in formalising sleep medicine as part of the residency curriculum.