During a customary visit to a prison on Holy Thursday, Pope Francis revealed that he has cataracts and is planning to have an eye operation to correct them next year.

The head of Regina Coeli prison in Rome made a comment during the visit about the importance of being "far-sighted" about prisoners' rehabilitation.

Pope Francis responded, "This is good. Because at my age, for example, cataracts arrive and one does not see reality well. Next year, we will have to have an operation."

He encouraged the inmates to have clear eyes – what he called "cataract surgery for the soul" – in order to see and spread hope.

Cataracts, a clouding of the eye's lens that is common as people age, is usually correctable with a routine surgery.

The pope, who turned 81 in December, maintains a rigorous schedule and still makes several international trips per year. He had a portion of one lung removed when he was young, due to an infection, but is considered to be in generally good health.