Updated

Gov. David Paterson has been diagnosed with acute glaucoma in his left eye and was undergoing an outpatient laser procedure Tuesday, his office said.

The governor, who is blind in his left eye and has only limited vision in his right, received the diagnosis after admitting himself to a hospital with symptoms of a severe headache. He was undergoing an iridotomy, an operation that will not have any long-term impact on the governor's overall health, a statement from his office said.

"The governor will remain conscious throughout the procedure, but in an abundance of caution, the Senate majority leader and the Assembly speaker were advised of this pursuant to standard protocol," the statement said.

Paterson went to The Mount Sinai Medical Center earlier Tuesday after experiencing what his office called "migraine-like symptoms" in the middle of the night.

Dr. Gregory Harmon, a Manhattan opththalmologist and chairman of the Glaucoma Foundation, said it sounds like the governor probably suffered an an attack of acute angle closure glaucoma, which is an emergency situation that occurs when fluids that normally drain freely from the eye suddenly become completely blocked.

The condition leads to an immediate buildup in pressure within the eye. It is incredibly painful, and causes not only headaches but, in some cases, vomiting due to the severity of the agony.

Harmon said the best treatment is an emergency laser iridotomy, which creates a microscopic hole in the iris that lets fluid drain. The procedure is brief, relatively risk-free, and usually clears up the problem instantly.

Paterson, who lives in the governor's mansion but has an apartment in Harlem, was in New York to speak at Tuesday's commencement at Columbia University, where he earned a bachelor's degree. The Democrat was to receive a medal of excellence but his office canceled the appearance.

His wife, Michelle, came to Mount Sinai several hours after he checked in.

Paterson, who turned 54 Tuesday, was sworn in as New York's governor March 17 after former Gov. Eliot Spitzer resigned amid a prostitution scandal. He had served as Spitzer's lieutenant governor for 14 months.

When he succeeded Spitzer, New York was left without a second-in-command; voters won't pick a new lieutenant governor until the next gubernatorial election in 2010.

Senate Majority Leader Joseph Bruno, a Republican, is next in line of succession. Bruno said he learned the governor was in the hospital around 6 a.m. Tuesday.

He noted that Paterson had recently put him in charge of the executive branch when the governor was in Washington for meetings, and greeted him on the phone with, "Hi, governor." The two men are friends.

The legally blind governor lost most of his sight after an infection as an infant. He can see shapes and usually recognizes people as they approach.

He can read for just a few minutes at a time, with the text held close to his face; usually his aides read to him. At a bill signing last week, Paterson put his nose to the bill to find the right lines on which to sign.

Paterson's health has been a concern in recent years, with at least two other hospitalizations, although he is known for his basketball skills and also ran the New York City Marathon.

In April 2006, when he was state Senate minority leader, Paterson was admitted to a hospital with chest pain and underwent a CT scan, cardiovascular stress test and echocardiogram. The tests came back normal and he was released after about 12 hours.

Last July, Paterson fainted on an airplane on his way to Buffalo. He was briefly hospitalized and the following day had an angiogram, which was normal. Doctors said they found no evidence of heart disease.