Professor Collin trained at Cambridge University and Westminster Medical School with ophthalmology training at Moorfields Eye Hospital. He undertook plastic surgery training at Queen Victoria Hospital, East Grinstead. He had an oculoplastic fellowship at University of California, San Francisco.
Professor Collin has been appointed as honorary consultant to Great Ormond Street Hospital for Sick Children and consultant eye surgeon to Moorfields Eye Hospital with special interest in eyelid surgery. He continues to take part in research, books, lectures and multiple published papers on eyelid surgery and related subjects.