ROME (REUTERS) - Pope Francis on Thursday (March 29) disclosed that he had cataracts and expects to have an operation next year.

During a visit to a Rome prison, Francis, 81, responded to words by the institution's director about the need to be"far-sighted" about the rehabilitation of inmates.

"This is good," the Pope said.

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

Cataracts are a clouding of the eyes' natural lens and are common in elderly people.

Surgery to correct them is considered routine and has a very high rate of success.

The Pope has not been hospitalised since his election as Roman Catholic leader in 2013 and appears to be in overall good health.