Although a detached retina is not an uncommon injury among professional boxers, prefight physical examinations in three of the most active boxing states--New York, New Jersey and Nevada--do not routinely include examinations by eye specialists that might detect such an injury.

Had world welterweight champion Sugar Ray Leonard gone ahead with his scheduled title defense against Roger Stafford Friday in Buffalo, rules of the New York State Athletic Commission would have required him to undergo a physical examination five days before the bout.

But, although the physical would have included an eye examination, it would not have been done by a specialist, and, unless Leonard had complained that his eye was bothering him, the condition could have easily gone undetected.

Sunday, Leonard underwent two hours of surgery at Johns Hopkins University Hospital's Wilmer Eye Institute to repair a partially detached retina in his left eye. He was reported in good condition yesterday, but doctors say it may be weeks before they will know for sure whether or not there will be a complete recovery. It will likely be several months before there is a decision on whether or not Leonard will resume his boxing career.

Saturday, Leonard abruptly interrupted his training schedule in Buffalo and flew to Baltimore, where he checked into the Wilmer Institute. Leonard acted after a Buffalo eye specialist detected retinal damage and recommended further testing following the boxer's complaints that he had been seeing spots in his left eye over the previous two weeks. The Stafford fight was postponed indefinitely.

Marvin Kohn, New York's deputy athletic commissioner, said that only if the examining physician had detected something amiss at the mandatory prefight physical or if Leonard had complained of eye trouble would an ophthalmologist have been called in to examine Leonard further.

"A doctor can spot a lot of things, but he's also dependent on the information the boxer gives him," Kohn said.

Monday, Harold Weston, a fighter who underwent surgery for a detached retina after a 1979 fight with Thomas Hearns in Las Vegas, said that in 40 professional fights he never had a prefight retinal examination.

"If you took all the fighters today and gave them serious eye exams, you'd probably find 30 to 40 percent have partially detached retinas," Weston said. The retina is the sensory membrane at the back of the eye that receives light images and transmits them to the brain. Without the retina attached to the eye, sight is impossible.

Dr. Leonard Parver, director of the eye trauma unit at Georgetown University Hospital, said, "It's far less likely that someone who is not an ophthalmologist would detect a detached retina if there are no symptoms. It might require at least an opthalmologist and probably a retinal specialist."

Robert W. Lee, deputy athletic commissioner for New Jersey, said the policy in that state is similar to that in New York; an examination by an ophthalmologist is required only if symptoms appear to require it or if the fighter has a history of eye trouble.

Sam Macias, chairman of the Nevada Athletic Commission, said the state requires weigh-in physical examinations of fighters by commission doctors, but that for a fighter who comes into the state for a single championship fight, "We don't require a complete physical unless we have heard there is something wrong."

In Washington, York Van Nixon, chairman of the D.C. Boxing and Wrestling Commission, said general prefight physical examinations are required of fighters but that specialists are not called unless there appears to be a specific reason. Were Leonard to fight in Washington now, he said, he would have to submit a clean bill of health from two ophthalmologists.

In New York, according to Kohn, records of the athletic commission show 11 eye injuries since 1979, six of them detached retinas. In an effort to cut down on such injuries, the state has required fighters to use thumbless gloves in all four- and six-round fights. Recently, that requirement was expanded to include eight-round bouts and, within a few months, it will likely be made mandatory for 10-round fights, Kohn said.

But he also said fighters are resisting the regulation. "They say it hurts their thumbs to fight with thumbless gloves." A number of eye injuries in boxing are believed to occur when a fighter is jabbed in the eye with a thumb.

At Johns Hopkins yesterday, Leonard, 25, was said by nurses to be cheerful. He was visited by members of his immediate family and close business associates, but tight security measures kept him isolated from the public and the media.

A hospital spokesman said he could leave the hospital, possibly as soon as this weekend, to continue his recovery at his Mitchellville, Md., home.