Following a rare look into Medicare payments, one South Florida ophthalmologist has emerged as the program's highest-paid individual doctor. In 2012, Dr. Salomon Melgen of the Melgen Retina Eye Center received $20.83 million from Medicare. On his website, Melgen, who has been practicing for more than two decades and graduated from a Dominican Republic university, claims to be the only Hispanic ophthalmologist in Palm Beach, St. Lucie and Martin counties.

Dr. Salomon Melgen Mark Elias | Bloomberg | Getty Images

While this payout is large, it's still a small fraction of the approximately $77 billion in Medicare payments that more than 880,000 distinct health-care providers received in that year. Read MoreSliver of Medicare doctors get big share of payouts Melgen's emergence as the federal health program's highest-paid physician comes amid a criminal investigation of Melgen's alleged excessive Medicare billing practices the Miami Herald reported. The paper added that Melgen is known to be a close friend of U.S. Sen. Bob Menendez, D-N.J.