Medicare paid nearly 4,000 doctors and medical professionals more than $1 million apiece in 2012, including seven who received more than $10 million. Eye doctors were among the highest compensated, including one Florida ophthalmologist paid $21 million in 2012.

The disclosures were gleaned from a trove of $77 billion in payment data released by the government this morning that provides the first look at Medicare payments to physicians in more than three decades.

The massive data file covering 880,000 providers showed concentration at the top, with the doctors over $1 million receiving at least 13 times the $77,000 average paid by the program. The data showed that cancer doctors specializing in blood work and radiation are those best compensated by Medicare, each averaging over $360,000 in annual payments from the program for the elderly and disabled, which is the largest health-care payer in the U.S.

“This is an enormous event and momentous day and a long time in coming,” said Bob Kocher, a former special assistant to President Barack Obama for health care policy, in an interview. “What it’s going to help us do for the first time is figure out what these doctors actually do and what kinds of patients they actually see.”

While drug and hospital costs have been scrutinized, less attention has been paid to doctors’ fees, which accounted for about 12 percent of Medicare’s budget in 2012. Making the data available may allow the public and researchers to better identify fraud and waste by doctors in the $604 billion Medicare system.

More Heat

The data could also put more heat on doctors who engage in self-referral -- ordering up tests and procedures that are performed in their own clinics or in those in which they have a financial interest.

The data release has been lauded by consumer groups seeking to spotlight possible fraud or overuse and criticized by physicians, including the American Medical Association, whose head has said misinterpretation could ruin doctors’ careers.

Medicare payments to doctors were kept from the public after medical associations argued in the early 1980s that their release would violate physicians’ privacy. Last May, a federal judge lifted a 33-year-old injunction on the data following a lawsuit by Dow Jones & Co.

AMA Fought

The Obama administration decided last week to make all payment information public, excluding for privacy purposes cases in which doctors performed procedures on fewer than 11 patients.

Consumers can now see aggregate sums paid to a doctor, how that amount compares to their peers and which doctors made the most from the program. They can also see the type and how many procedures a doctor billed Medicare for.

“It will benefit not just consumers and the taxpayers but ultimately the health-care sector because it will shine some light in some dark corners where, frankly, health-care providers should improve the way they practice,” said Joe Antos a scholar at the American Enterprise Institute.

The AMA, which fought to keep the information private said the data lacked context. Some doctors may be making more than the average from Medicare because they see a disproportionately high number of elderly, not because they are improperly billing the agency, according to Ardis Dee Hoven, president of the AMA. In other instances, a doctor may be doing more of a certain procedure because they have specific expertise in that area or better outcomes, she said.

Patient Complexity

“We are bracing for some significant unintended consequences,” Hoven said. “Patients may not get the right data and the outliers are going to have to stop what they are doing and be replying to folks day after day when nothing is out of kilter and they are just doing their jobs.”

The data do not include information on what percentage of a doctor’s practice is Medicare versus private insurance patients. Some of the numbers may be inaccurate and doctors haven’t been given a chance to review it and make corrections, Hoven said.

“We fear this information can be easily misinterpreted without a complete understanding of patient complexity and the cumbersome Medicare billing system,” said American College of Cardiology president Patrick O’Gara in a statement.

Eye Medicine

Medicare. which covers 49 million people, spent $5.6 billion on payments to ophthalmologists, driven by new treatments for blindness. That was second only to internal medicine doctors, generalists who were paid a total of $8.7 billion in 2012. Cardiologists, third in Medicare’s classifications, received $5 billion.

Payments to the more than 800,000 doctors in the Medicare program varied widely with the top 25 highest paid doctors receiving between $21 million and $6.5 million. A dozen of the top 25 highest paid doctors were ophthalmologists.

Medicare officials would not discuss specific doctors, Aaron Albright, a spokesman for the U.S. Centers for Medicare and Medicaid Services, said by phone. He didn’t immediately answer other questions about the data and Medicare’s use of it.

The spending in opthalmology is being driven, in part, by new medicines administered in doctors’ offices to treat macular degeneration, the leading cause of blindness in the elderly.

Shining Light

Also included were payments to laboratories, group practices, ambulance services, and mobile x-ray providers. Multiple entities with Quest Diagnostics in their names collected a total of $669 million from Medicare, and listings for Laboratory Corporation of America Holdings totaled $717 million. The data generally are totaled by location, not by parent company, so it’s not possible to be certain that all those with a common name are owned by the same company.

California and Florida received the largest payments with each getting more than $7 billion from Medicare followed by Texas and New York, with $5 billion a piece.

The Centers for Medicare and Medicaid Services is hoping that by releasing the data it can help cut waste from the Medicare system and improve cost-effectiveness, Jonathan Blum, deputy administrator for the Medicare agency, said last week in a blog post on the decision.

“Data like these can shine a light on how care is delivered in the Medicare program,” Blum said. ’’Businesses and consumers alike can use these data to drive decision-making and reward quality, cost-effective care.’’

The move has been welcomed by health research firms and consumer groups who’ve been looking for insight into how Medicare spends its money.

Senior Politics

“I think by and large it’s really important for government to release these kinds of data,” said Dan Mendelson, founder of consulting firm Avalere Health LLC. “It’s good government practice. You want to have an informed consumer thinking about cost and quality. That’s the goal.”

Political considerations may discourage Medicare officials from more aggressively mining payment data for evidence of fraud and waste, said Kirk Ogrosky, a partner at the law firm Arnold & Porter in Washington and a former federal prosecutor who led a Medicare fraud unit. His current clients include a doctor who is suing to overturn a ruling that he over-billed Medicare.

“Running Medicare is a political hot potato. It’s a lot of money,” Ogrosky said. “And every time granny doesn’t get her walker someone’s up on Capitol Hill complaining to their congressman.”

The agency has walked a fine line between going after abuse by doctors and ensuring they don’t make doctors less likely to take Medicare or high risk patients, said Kocher.

“Medicare has this tension between putting in controls to mitigate the risk that there’s fraud with stifling the growth of small business and doctors trying to innovate,” he said. “Medicare should use this data to identify outliers and people who have patterns that are exceptional, to be better. Frankly, by making this data public maybe there will be some innovations in how this data can better be used by Medicare.”