For more than two years, Dr. Singh worked as a general practitioner in the rural hinterland and also performed eye surgery. After obtaining his master's degree, Singh returned in May 1964 to Amritsar as a senior lecturer in ophthalmology. He later transferred to
Government Medical College, Patiala, for five years. Singh served as a member of faculty of the Government Medical Colleges in Amritsar and Patiala for 23 years and became an Emeritus professor of the institutions. He did pioneering work in lens implants beginning in 1976 and the Fugo technique "plasma scalpel" for glaucoma and cataract surgeries. He was an innovator with Trans-ciliary Filtration (invented in 2001) and the Pre-Tenon Tangential Micro Track Filtration. He was the discoverer of
lymphatics in the eye. He wrote over a dozen books on ophthalmology, and also a non-technical book
Naroi Akh (Healthy Eye) in Punjabi decades ago. ==Other endeavors==