Lucentis, made by Genentech, costs nearly $2,000 per injection into the eye, as often as once a month. A Genentech cancer drug, Avastin, can also be used off label to treat eye disease, at a cost of only about $50 per injection — although that choice is not without its own issues.

Dr. John C. Welch, a Nebraska eye specialist who received $9.5 million in Medicare payments in 2012, said the high reimbursement was the result of treating large volumes of patients and the cost of the injections. He says he does not profit significantly on any of the drugs he uses, making less than 3 percent on Lucentis. (That he would profit at all is hotly debated in the world of medicine. Some experts contend doctors should not profit at all from the drugs they use.) He said he preferred the drug because his patients were able to go longer between treatments. He also said patients were more comfortable with a drug that was approved by the Food and Drug Administration — as Lucentis is — and did not have to be prepared in a special pharmacy, as does Avastin. He said he was now using a newer drug, Eylea by Regeneron, because it seemed as if patients could be treated less frequently.

The prices of these drugs, and the difference in approvals, is not the fault of the doctors, he said. “It’s basically a problem created for us by the Medicare system,” he said.

Many of the cancer specialists who are also highly reimbursed are also purchasing chemotherapy drugs, the cost of which is also included in what Medicare pays them. Experts say the payments also do not reflect the cost of expensive equipment that a doctor may use in treating patients.