Dr Theng is the founder, Group Chairman and Medical Director of Eagle Eye Centre. He graduated from the National University of Singapore (NUS) in 1992 with MBBS degree. Obtained post graduate qualifications, MMED (Ophth), FRCS (Edinburgh) and FRCOphth (London).

As a cornea specialist, Dr Theng has since developed his surgical skills leaning towards the areas of LASIK & Refractive Surgery, Cornea Transplants, as well as Cataract Surgery while maintaining his special interest in the field of Presbyopia management and treatment. Being a high-volume cataract surgeon, Dr Theng was selected to represent to conduct the Phase 4 Clinical FDA approval trial for the Restor +300ADD Multifocal Lens Implants. Dr Theng has since regularly performed multifocal lens implants in cataract surgery, and even wrote a book about Presbyopia. He also continues to bring in different cataract management techniques in Asia.

A sought-after speaker who has spoken at global conferences, such as the World Ophthalmology Congress and others, Dr Theng travelled the world to lecture and teach on LASIK, cataract and presbyopia treatments. He is also a member of Editorial Board for the Journal of Cataract & Refractive Surgery Today (CRST) Europe and represents Asia as an advisor in the field of Cataract and refractive surgery for Alcon, AMO and Ziemer.