Ticket personnel at Baltimore-Washington International airport are accustomed to international travelers who try to bend the rules about carry-on luggage; they try to be tolerant. But there is a limit, and the well-dressed party of four embarking for New York's Kennedy Airport had gone beyond it. The dapper young man, his elegant brunet wife and their two friends wanted to carry on board four attache cases, one packing box, and a sealed Styrofoam cooler.

The passengers refused to check the parcels. Why not? Did passenger Michels need to study material from the four cases in flight? Was there something in the box so precious that his wife Alice could not be parted from it even for an hour or so? Or did passengers Rice and Stark -- a boyish-looking man with round tortoise-shell glasses and a stocky man with an infectious laugh -- plan to sample a few beers if the plane was stuck in a holding pattern?

Not exactly. In fact, the skeptical clerk was told, this was a team of American surgeons, and the boxes contained precision surgical instruments and medication. They were on a mission of mercy. Their destination: Moscow. Their patient: well, they had no idea.

In time the counter clerk was convinced. And the world was convinced as well last October, when the three surgeons from John Hopkins University's Wilmer Eye Institute annonced to the press that they had flown to Moscow, performed delicate eye surgery on a high official of the Soviet government and very possibly saved his eyesight.

The three -- primary surgeon Ronald Michels and his associates, Tom Rice and Walter Stark -- still refuse to reveal the name of their patient, though they are willing to deny press reports that he was Soviet President Leonid Brezhnev, who has been in failing health for some time. The name of the patient is just one of the unanswered questions in the story of their extraordinary trip to Moscow, a mystery story of medical cooperation. They don't know all the answers themselves, they said in a recent interview.

"There were many things that were never said," recalled Michels of his eight-day trip through the East-West looking glass. "We always knew the essential features of what was going on, but there were a lot of the details that we were never told and many of which we never inquired about."

The story begins last May, with a visit to the United States by Academician Mikhail Mikhailovitch Krasnov, Lenin Prize laureate, Hero of Socialist Labor and dirctor of the All-Union Scientific Insititute of Eye Diseases, located at No. 5 pogodinskaya St., Moscow, just two miles from the Kremlin wall.

The ostensible purpose of Krasnov's trip was to visit a number of medical conferences in this country -- something the well-traveled, multilingual ophthalmologist had been doing for years. So when Krasnov casually mentioned to his American opposite number, National Eye Institute director Carl Kupfer that he was interested in a new type of eye surgery known as vitrectomy, Kupfer thought little of it. He arranged for Krasnov to visit his old alma mater, the Wilmer Institute, and talk with Dr. A. Edward Maumenee, retiring director there, and then Kupfer forgot about it.

But unbeknownst to his friend and colleague, Krasnov had come to the United States with another mission. He attended a Wilmer faculty meeting at which Ron Michells, a surgeon with a growing reputation in the new field of vitreous surgery, showed slides of a case in which he had used microminiaturized surgical instruments to remove a membrane that was blocking the sight of a patient's eye.

Krasnov showed great intererst in the technique -- so great that Michels invited him to don a blue gown and watch in the operating room as Michels performed another vitrectomy -- a delicate procedure which removes some of the clear gel that fills four-fifths of the human eye. Krasnov watched Michels manupulate the tiny instruments through an operating microscope equipped with a "beam-splitter" that allowed him to share Michels's view.

Afterwards, he sought out Maumenee with a courtly but startling request. "He asked me, as the Europenas do, would I allow him to ask Dr. Michels to Russia?" Maumenee recalled. "I said, 'Sure, if you invite me, too.'"

When Krasnov tendered his invitation, Michels suggested it might make more sense to have the patient travel to Baltimore, where the instruments were already in place. No, said Krasnov politely, it would not.

"It was clear to me," Michels said, "that probably it was a government official."

Michels and Maumenee recruited Walter Stark, a friend and colleague who specializes in corneal surgery; they agreed to make the trip as a team. (Eventually, when arrangements dragged on into the fall, schedule conflicts forced Maumenee to pull out; his place was taken by Tom Rice, a junior retinal and vitreous surgeon at the insitiute.)

It was an extraordinary invitation. Michels and Stark had operated in foreign countries before, but always as part of trips to medical conferences. This would be their first trip as a surgical SWAT team. And of course there was the prospect of oeperating on a top official of the Soviet Union, a nation they had never visited and about which they, like most other yamericans, knew very little. But the prospect did not dismay them: like most top surgeons, they have quite an adequate fund of self-confidence, and besides, after a full day of surgery they found they had little time or energy left to worry about the future.

In June, Michels received a visit from Robert Kashtanov, first secretary of the Soviet Embassy in Washington. A balding man with a heavy mustache and thick glasses, Kashtanov is one of two medical doctors attached to the embassy. He and the counselor for medicine, Mikhail Borisov, had been briefed by Krasnov during his visit the month before. "At that time maybe we didn't know if it would be possible," Borisov recalled. But in June, the official letter of invitation, signed by Krasnov, arrived in a diplomatic pouch, and Kashtanov delivered it. "We agreed about the visit" on his visit to Hopkins, Kashtanov said. "After that there was some preparation -- some delay."

Before the trip, the Soviets had to buy the complex and expensive vitreous surgery equipment and get it in place in their hospital in Moscow. The device Michels uses is called an Ocutome. It is manufactured in California, and costs $13,000. Michels placed the order, and Cooper Laboratories, the manufacturer, sent their Geneva-based European representative to Moscow to perform the delicate installation there.

This took time; and, in addition, there were schedule conflicts for the three doctors. It was never quite made clear, but the Americans also got the impression that the patient had to fit the operation -- which can require a week of hospitalization -- into a demanding schedule. Arrangements dragged on : the doctors talked to the embassy; the embassy talked to the Ministry of Public Health in Moscow; the ministry talked to the attending physicians; the physicians talked to the patient. "Finally it was clear that the instruments were there and this was the time to go ahead," Michels said. They had 10 days' notice: they would leave October 12.

After the brief delay at the Allegheny gate, the trip to Moscow went smoothly. A well-briefed representative of Aeroflot, the Soviet airline, greeted them at Kennedy Airport. The attache cases and the cooler -- which held a special irrigating solution for the eye, packed in ice -- rode proudly beside them in first class on seats of their own.

It was not until 10 a.m. Moscow time the next day that they began to realize quite how important to their hosts this mission was. This first glimpse of the Soviet Union was a big black limousine with an antenna on the roof. It was waiting on the tarmac when their plane landed, beyond the passenger gate and security checkpoints; and it was waiting for them.

Waiting by the limousine was Academician Mikhail Mikhailovitch Krasnov. A silent aide disappeared with their passports. While their fellow passengers waited in the customs line, Krasnov led them to a private lounge, where there were comfortable chairs and a bar, gleaming bottles of mineral water and soft drinks.But no vodka; Krasnov, made it clear that their mission would begin at once, today, as soon as they had a chance to change their clothes.

"That was the thing that surprised us most," Michels recalled. They had looked forward to a leisurely day of unpacking, relaxing, overcoming the eight-hour time difference. But Krasnov insisted that their patient was ready for them now; if all went well, surgery would be the next day.

The aide returned with their passports; the party piled into the black limousine and sped of toward Moscow. Two hours later, hastily showered and changed, they were in a conference room of the Clinical Hospital of the Ministry of Public Health. This elegant facility, though located several miles from Moscow's ancient walled fortress, if often called Kremlin Clinic, because it treats important officials of the Soviet government. It is a nine-story building, very new and surrounded by a high concrete wall, with a uniformed guard at the entrance gate. The three doctors noticed that it seemed to treat very few patients at a time.

Twelve Soviet physicians were in attendance as Krasnov carefully reviewed the case with the three Americans. The atmosphere reminded Michels of grand rounds at an American teaching hospital. "Everybody was mobilized for this single case," he said. There was only one thought on anyone's mind, and that was, 'Let's get the job done right.'"

After a 90-minute review of the case, the Americans were led into an examining room next door to meet their patient -- and learn his name for the first time.

"During the entire time that the case was being presented and discussed, the identity of the patient was not revealed," Michels said.

None of the three can quite recall who called who asked them to keep the patient's name a secret. It was not the man himself, whom they uniformly describe as gracious, sophisticated and polite. Of course, it is not an unusal request. Very few patients of any rank or nation would want their doctors to discuss their cases with the press. And when the patient is an official of a government -- any government -- his effectiveness in office may depend on a reputation for good health and vigor.

"We were never intimidated in any way and we were never restricted in any way. We were told several times, "Do what you want.' But we felt that we wanted to abide by the wishes of the people who brought us there -- also generally accepted as the practice of medical principles," Michels said.

But to outsiders, the secrecy adds to the air of unreality -- the fairy-tale quality of the three doctors' trip through the looking glasses. They, for their part, are unwilling even to give hints that would help the curious zero in on which member of the Soviet hierarchy they treated. Thus, they will not discuss whether the man's eye problems were related to diabetes -- frequent cause of this type of disease. Some members of the Politburo, they point out, are known to suffer from diabetes.

One by one, the three Americans examined their new patient, while Krasnov and a few colleagues looked on. They first scanned the front part of the eye with a split lamp, then placed a contact lens on the pupil so they could see the rear part of the eye -- where the trouble was -- through a device called an indirect opthalmoscope. What they saw confirmed what they had heard: a tiny membrance of scar tissue had grown over the retina of the eye, distorting vision and partially blotting out the light. The retina, a structure which coats the rear of the eye, translates light into nervous impulses and sends these to the optic nerve, which conveys them to the brain. Because of the membrane, the patient had lost most of his vision in the affected eye, and in this country would be considered legally blind. Vision in the other eye was better, but still not normal.

The vitrectomy opertion can unquestionably help many such patients regain part -- though not all -- their sight. But there are some dangers, and the Americans were looking for "contraindications," danger signals that would mean surgery would not help and might even make things worse. For example, the membrance might appear to be tightly attached to the retina; if so, removing it might damage the sensitive tissue beneath. Or there might be scarring, or a hole in the retina, or the retina itself might be detached from the tissue beneath; if so, the operation would do no good.

Though vitrectomies are becoming increasingly common, membranes on the retina are relatively unusual; Ron Michels, who has performed more than 1,500 vitrectomies, encounters such a case once or twice a year. But the three concluded that surgery would probably help the patient. It was, Michels recalled, a "middle-ground" case, in which the vision would probably improve to about halfway between its present level and what it once had been. "There were some subtleties involved," Michels said. "But it didn't differ greatly from other cases that we've done that were similar."

Back to the paneled boardroom, where they explained their conclusions to the 12 Soviet physicians, and then to the patient himself. The operation would probably help; but there is always a chance of complications that would blind the eye altogether. There might be a sudden hemorrhage during surgery, or the retina might become detached from the optic nerve. After surgery, an infection might set in.

"That is an infrequent complication," Michels said. "But it is a dread one.

The doctors concurred; after an interpreter explained the case, the patient agreed as well. Surgery would be the next day. The big black limousine took them back to their hotel.

They were staying at the Sovietskaya Hotel, four miles from the center of town. This is not where you or I will stay when we visit Moscow for a week's vacation; it is reserved for visiting dignitaries and guests of the Soviet state. The building is pre-revolutionary; inside, it is paneled in dark wood, carpeted with heavy rugs from Soviet central Asia, lighted by glittering chandeliers. Ron and Alice Michels were given a suite of honor -- office, dining room, bedroom. Stark and Rice had luxurious single rooms. They ate in a private dining room and went to bed.

The big black linousine took them to the hospital at 9:30 the next morning. At 10:30 the patient was anesthetized, and at 11 a.m. they were ready to begin. Ron Michels took up his position at the patient's head; Rice stood at his right, ready to manipulate the contact lens that allowed the surgeon to see inside the eye. Stark and Krasnov stood at Michels' left, ready to help with instruments. Also in the operating room were two scrubbed nurses, the hospital's chief anesthesiologist, its chief ophthalmologist, and the chief of interpreters for the Ministry of Public Health, Rice, Krasnov and Stark watched through the beam-splitter as Michels made the first delicate incision in the side of the eye.

"Pars plana vitrectomy" or "closed vitrectomy" is less than a decade old. The surgeon uses microminiaturized surgical equipment to enter the back of the eye and remove part of the "vitreous humor" -- the clear, getalinous substance that fills four-fifths of the eye. The technique was developed in 1970 by Dr. Robert Machemer, a german-born surgeon who was then at the Bascom Palmer Eye Institute of the University of Miami.

Problems with the vitreous humor (often called simply "the vitreous") are common in the elderly; the most common cause is adult-onset diabetes, which can cause blood leakage and abnormal blood vessels inside the eye. The blood leaks into the vitreous and clouds the gel until vision is lost. Until the development of vitrectomy, nothing could be done for these patients, who are quite a sizable group. Diabetes is the second largest cause of adult blindness in this country; the disease affects 10 million Americans, and the number is expected to double by 1990.

Machemer's colleaugues at Bascom-Palmer had been experimenting with a techniuque called "open-sky vitrectomy," which involved removing the lens of the eye, scooping out the vitreous and then replacing the lens.

"I thought, Gosh, that should be done more elegantly," Machemer recalled. "Why do you need those big coarse instruments? Why do you remove the lens with a big wound?" He consulted with Jean-Marie Parel, a Swiss-born engineer then working in Australia. Together, they designed an instrument that could hardly be called coarse, the Vitreous Infusion Surgical Cutter.

The VISC is shaped like a fountain pen, but slightly larger, instead of a nib, it ends with a needle, one inch long and 1/64 of an inch in diameter. Inside this tiny extrusion is a miniature assembly that can simultaneously cut away diseased tissue and suck it out through a tube, pour in sterile solution to replace it, and provide working light by means of a fiber-optical "light pipe."

Using a VISC, a surgeon can enter the back of the eye -- where most vitreous problems occur -- without wounding or distrubing the front. The device enters through a tiny needle hole, suck out the vitreous and then exits cleanly, requiring only a small suture to close the hole.

Astonishing as such a miniature marvel may seen, engineer Parel, who now heads an instrumentation laboratory at engineering. "It's not that difficult really," he said. The VISC has about 30 moving parts, while "if you think of a watch, it has 100." v

Machemer performed the first closed vitrectomy in 1970; in 1972, Michels came to study under Machemer at Bascom Palmer. By 1974, the operation had become so popular that 13 companies were manufacturing instruments to perform it; competition has seen the field narrowed to four.

The Ocutome, which is now the most popular vitrectomy system, performs the same functions as the VISC; but instead of one needle, or "probe," the Ocutome uses three tiny incisions -- through one, a probe enters for cutting diseased tissue and removing it; a second "fiber-optical" probe provides lighting; through a third, the device pours in new liquid. The cutting needle is .89 of a millimeter in a diameter. Michels used this to suck out part of the vitreous humor. Then he took up the task of teasing the membrane away from the retina.

This is the most delicate part of the surgery, occupying perhaps 15 minutes. To perform it, Michels used a special set of miniature tools which he himself had designed in cooperation with Mentor, a surgical-instrument corporation in Massachusetts. Using these, he had to find out how tightly attached to the retina the membrane is, then peel it away, if possible in one piece. If it is attached at too many points, it may split into tiny pieces that cannot be completely removed. There may also be a sudden hemorrhage in the eye, which would undo the good the operation might achieve.

Once the membrane was loose, Michels re-inserted the cutting probe to chop it into mini-bite-size portions that would fit inside the opening in the needle. Within that tiny sliver was a guillotine-style chopping device, powered by bursts of compressed air, which cut the tissue up even smaller and then sucked it up another pipe. Michels controlled the cutting action of the guillotine with a foot pedal. "It's like driving a Volkswagen," he said. "You use both hands and both feet."

The membrane -- two millimeters in diameter and 0.1 mm in width -- was consumed, the surgeons checked out the retina, and the operation was over. When they were finished, they were astonished to realize that it was past 1:30 p.m. Usually vitrectomy takes about 90 minutes, but in this case it had taken nearly twice as long. No one had noticed the time while the operation was underway.

After the patient was wheeled away, the three surgeons were shown to the same boardroom where they had consulted with the 12 Soviet physicians the day before. Spread out on the table was a banquet -- salmon, caviar, vodka, soup, roast meat, dessert. The surgical tema celebrated, Russian-style, and the exhausted Americans were toasted in vodka and called on to toast back. None of them can quite remember what they said. "There was some comment that the surgery had gone well and so forth," Tom Rice said.

While they were finishing their meal, word came that the patient was awake. Michels and Krasnov quickly went to examine him. There were no complications, but it was too early to tell if his vision had truly improved. There would be seven days of follow-up examination.

That night, their guide and interpreter took them for a walk in the Kremlin grounds. Afterwards they had choice seats for a performance by the Bolshoi Ballet in the Kremlin library, and a dinner in their private dining room at the Sovietskaya at 10:30. Then the Americans tumbled into Sovietskaya feather beds, the main purpose of their visit accomplished.

"It was a pretty long day," Michels said dryly. But the days grew short from then until the 21st, when they returned. The routine was established quickly: up early in the morning, chauffeured limousine to the hospital (Alice Michels, meanwhile, had her own car, driver and interpreter); examine te patient in the hospital room; report on his progress to the 12 Soviet doctors in the board room. As the week went by, it became clear that his vision was improving. Michels says they will not be sure how much until Krasnov's visit to this country next spring.

By noon each day, they were free to tour the city. Perhaps "free" is too strong a word. Their days were meticulously planned by Julia, their interpreter, who not only devised their schedule of tourism, theatrical events and banquets, but kept their wakeup calls and ordered their meals as well. "It always seemed to be the logical, appropriate thing," Michels said. "We were never asked to do anything particularly difficult, and if you were making the decision yourself, that was probably what you would have selected."

They saw Lenin's tomb, and the Kremlin apartment where the great man lived after the Revolution; they saw the Bolshoi twice more, and the Moscow Circus and a puppet theater. One day they drove to Zagorsk, official seat of the Russian Orthodox Church, for a private tour of the grounds. Afterwards, Julia had arranged lunch with one of the monks in residence there. The monk, a man in his 40s, seemed very interested to hear about the pope's trip to the United States. "We weren't sure he had known about it before," said Walter Stark.

It was, in short, a splendid week of leisure, of luxury such as few Russians or Americans will ever know, and of a feeling of accomplishment. They had stepped through the mirror, had done well what they were supposed to do, and now enjoyed the gratitude of the second most powerful nation on earth. The Russians entertained them so well that the three doctors agreed not to charge a surgical fee.

But there was not a moment during their stay in which they felt personally close to any of their hosts. They never learned Julia's last name, or visited any Russians in their homes. "It wasn't the sort of situation where you sit down and discuss your innermost emotions," Tom Rice said.

"Everything you say and do in that circumstance in carefully measured," Michels said. "There's less spontaneity than you might experience meeting with colleagues at home. You don't get particularly close to anyone on a one-to-one basis.'

Toward the end of their stay, Walter Stark called the U.S. Embassy in Moscow. Stark, an avid sports fan, is team ophthalmologist for the Baltimore Colts; he wanted to know the score of the World Series between Baltimore and Pittsburgh. He had tried to glean this information by tuning in the shortwave radio in Stark's room at the Sovietskaya; after some adjustment, he found an English-language broadcast he assumed to be Radio Free Europe. But the world news roundup did not included the baseball scores. When he called the embassy, a Marine guard brought him up to date on the series, then shifted him to a press attache, who offered to set up a press conference for the three Americans. Stark declined.

On their last afternoon in Moscow, however, the resident American press corps began calling the Sovietskaya. A rumor was sweeping Moscow that the three surgeons had operated on Communist Party chairman Leonid Brezhnev. Michels denied it. "I felt that it was such a significant error that at least I could say, No, it wasn't Mr. Brezhnev," he said later. But the calls kept coming, including an invitation to appear on NBC's "Prime Time Sunday," which they turned down.

When, on Sunday, Oct. 12, Aeroflot deposited them at the gate at Kennedy Airport, they found a gagle of American reporters waiting to pump them about the Soviet leader they'd treated. But they had stepped back through the looking glass: there was no limousine, no waiting delegation; in fact, the waiting reporters didn't even know what they looked like. So they slipped past them and went home to Baltimore.

The time in Russia now seems like a marvelous dream. "To me it was a very relaxing week," Tom Rice said. "It wasn't our usual hassled existence of seeing patients."

For their part the Russians profess not to understand the American interest in the trip by Michels, Rice and Stark. The three doctors may tell of the gleaming limousine, the guarded the glittering nights at the Sovietskaya Hotel; but the Soviet Embassy insists it was nothing more than a routine function of the socialist health care system.

"That was an ordinary operation," insists Borisov. "Dr. Michels used some new methods. But as for who the patient is -- I don't know. I didn't ask. A patient is a patient." Who Was the Mystery Patient?

Press reports originally speculated that the three American surgeons had operated on Soviet President Leonid Brezhnev, who has been in failing health for some time. When the surgeons denied this report, speculation then turned to Soviet party theoretician Mikhail Suslov. But authoritative American sources told The Washington Post that the patient was Konstantin Victorovitch Rusakov, 70, a former ambassador to Mongolia who now supervises relations between the Soviet Union and other nations in the Communist bloc.

One specialist on Soviet affairs called Rusakov "one of the 25 day-to-day string-pullers who rule the country." His job includes the job of handling relations with the satellite countries of Eastern Europe -- relationships which Moscow considers absolutely vital to its security. Since the time of the mystery operation, Rusakov has been seen in public at a ceremony reaffirming the treaty between the USSR and Vietnam.

The three doctors have refused to confirm or deny speculation about the patient's identity. "The patient seemed to be a very gracious individual," Ron Michels said. "He didn't speak English. . . . He's a very well-postured, very polished individual. I felt very comfortable in his presence and I imagine vice-versa."