The Prime Minister said it was the first time he had worn glasses in public although he had had them since June.
Mr Cameron put the glasses on as he scanned his papers but removed them as he answered questions from the committee of senior MPs.
Former prime minister Tony Blair revealed in 2001 that he needed glasses as the years took their toll on his eyes.
Mr Cameron wrote on Twitter: "Thanks to everyone who asked about my new glasses. I've actually had them since June."