The Scary Thing That Happened To Daniel Radcliffe's Eyes In The Original Harry Potter Movie

In 2021, long-time Wizarding World producer David Heyman told Empire (via Wizarding World Digital) a story about how Daniel Radcliffe's physical response to his green contact lenses created movie magic in the last scene of "Harry Potter and the Sorcerer's Stone" (which was the first to be shot).

"I'll never forget being on set that first day, filming the last scene of 'Philosopher's Stone' where Hagrid and Harry bid farewell at the railway station at Hogsmeade," he said. "Dan was wearing these contact lenses to make his eyes green, and he had an allergic reaction to them. His eyes were red and swollen and we had to take them out – we thought we may add that green digitally, though ultimately we decided not to because it felt artificial. But Dan's eyes were puffy and red, and oddly it was quite appropriate for the scene where he was saying goodbye to Hagrid."

According to Icon Eyecare, 1–5% of contact wearers develop an allergy to contacts. This is called secondary giant papillary conjunctivitis and causes redness, itching, and the formation of small bumps on the undersides of the eyelids.