Trained in ophthalmology in Perth, Western Australia, Assoc. Prof Barrett undertook specialty traning in the USA. He is a consultant ophthalmic surgeon and Head of Department at Sir Charles Gardiner Hospital.

Assoc. Prof. Barrett is founding and current president of the Australasian Society of Cataract and Refractive Surgeons and president of the Asia Pacific Association of Cataract and Refractive Surgeons.

He is the recipient of major international awards including the Ridley Medal (European Society of Cataract and Refractive Surgeons), the Binkhorst Medal (American Society of Cataract and Refractive Surgeons), and the Ridley Medal (Congress of German Ophthalmic Surgeons).