Doctors who do one of today's commonest operations -- putting new plastic lenses inside cataract patients' eyes -- defended them yesterday as safe restorers of eyesight in the face of charges that they often hurt, rather than help, vision.

One patient, actor Robert Young, testified that at age 72 he is able "to see and work again" thanks to the "miraculous medical breakthough" of a pair of these artificial lenses.

Young and the doctors urged the Food and Drug Administration -- and an FDA adivsory panel in special sessions -- to take no further action to curtail the lenses' use.

But new FDA Commissioner Jere Goyan said "I believe it is time to reevaluate" the safety data and "take whatever steps are necessary" to assure safe use. As first witnesses, he called spokesmen for Ralph Nader's Health Research Group who want to curtail use until more studies are done. Goyan credited the Nader group with stimulating the reevaluation.

The Nader forces were backed by Dr. Thomas Chalkley, Chicago ophthalmologist and Northwestern University faculty member. In the last 20 months, he said, he has operated to correct complications in 23 patients who had the plastic lenses inserted after cataract removal.

These 23 are among patients, now 100,000 or so a year, who chose to have artifical lenses put in one or, occasionally, both eyes after their own lenses were removed because of a cataract's clouding. The artifical lenses provide far better vision than do thick cataract glasses, and avoid the frequent care and reinsertion that contact lenses require.

Many older patients cannot manage contacts. Some people, like an airplane pilot-engineer who testified yesterday, find contacts unsatisfactory.

For the Health Research Group, Robert Leflar and Dr. Sidney Wolfe charged that thousands of eye doctors have rushed into profitable lens-planting, rather than awaiting some small, careful studies. They said hasty "mass marketing" has led to a "serious problem of adverse reactions.

They cited a California Blue Shield study -- though not completely reliable, they admitted -- indicating that 12 to 15 percent of Medicare patients who get implants may suffer complications up to three years later.

In reply, doctor after doctor -- assembled by Dr. Henry Clayman of Miami for the American Intraocular Implant Society -- testified for the lenses. They said:

The California study is unreliable, and complication rates after the implant procedure usually run no more than a few percent, which at most is only slightly higher than rates after cataract surgery without lens implant.

The FDA should set no further restrictions on the procedure and should leave the policing and training of any inadequate doctors to their fellow physicians. The FDA has already declared use of the lenses "investigational" rather than an established procedure.

These doctors urged FDA to complete a study of surgical results. Dr. David Worthen of San Diego, FDA advisory committee chairman, spoke of his "trust" in the nation's eye surgeons.

But one committeeman, Dr. S. S. Hayreh of the University of Iowa, said the current study is unlikely to yield clear enough answers, and he fears "some long-term tragedy totally unanticipated at present" because of scanty knowledge about what will happen after the implants have been in patients' eyes for some years.