In 1982, midway through his medical studies, he decided to focus on opthalmology after watching an eye surgery performed by Peter Eustace, one of his professors.
[4] He later specialized in Ophthalmology in New York and a Fellowship in Cornea, Keratorefractive and Anterior Segment Surgery at the University of Minneapolis, Minnesota.
[3] Daya began his career in New York City, where he served as director of cornea and external disease at the Catholic Medical Centre.
In 1993, Daya became the director and consultant ophthalmic surgeon of the Corneo Plastic Unit and Eye Bank at the Queen Victoria Hospital NHS Trust in East Grinstead.
[6] An article written about himself and the clinic after its 25th anniversary wrote that over the years the clinic has become “a reference centre for the Ophthalmic industry with international visitors regularly visiting to observe new technology.”[9] Through this, he has also worked in the fields of anterior segment and keratorefractive surgery,[5] and the use of femtosecond laser during cataract surgery in the NHS.
[2] In 2009 Daya delivered the Choyce Medal lecture to the United Kingdom & Ireland Society of Cataract & Refractive Surgeons.
[9] In 2012 Daya and his team performed restorative surgery on television personality Katie Piper, who had suffered blindness following an acid attack.