Gov. David A. Paterson had to undergo an emergency eye operation for a second time in a month on Monday, to relieve a bothering and painful build-up fluid in his left eye caused by his glaucoma.

The governor’s spokeswoman, Risa Heller, said that Paterson was traveling to New York City from the Capitol, in order to attend his son’s middle-school graduation ceremony, when he suddenly felt pain in his left eye. The pain was acute enough to make him change his plans and visit his doctor at Mount Sinai Medical Center.

The doctor determined that the governor’s glaucoma symptoms had returned, despite a laser procedure performed on the eye last month. The doctors had to do a short laser procedure to relieve the increased pressure on that eye and reopen the channel that had been blocked. After the surgery, Paterson was able to go and speak at the graduation ceremony as planned, receiving a standing ovation.

The governor was due for another medical evaluation last night, but his spokeswoman said he was supposed to return to Albany today.

The first laser procedure, known as an iridotomy, was performed last month, after Paterson was diagnosed with severe glaucoma. A few days later, he had the procedure repeated on his right eye.

The governor, who is 54 years old, is blind in his left eye and can only see colors and large objects with his right one.