The kind of health care you get and how much it costs depends a lot on where you live.

Take, for example, the way that doctors across the U.S. treat a chronic eye disease, known as wet age-related macular degeneration, that among older people had long been a leading cause of blindness.

There is no evidence that the disease varies from place to place. But as recent Medicare data show, the way that doctors’ treat it does, and those choices have huge effects on the U.S. and personal budgets.

This map shows how the use of Lucentis, the most expensive of three drugs used to treat it, varies across the country. The brightest reds show places where the vast majority of the money spent in treating the disease is spent on Lucentis; the deepest blues, shows places where most of the money spent treating the disease is spent on its cheaper alternatives.

Steven Rich/The Washington Post

The three drugs doctors choose from are Lucentis, Eylea, and Avastin. Lucentis costs the most, at about $2000 per dose, and Eylea is slightly less, but Avastin is much cheaper, at about $50, according to 2012 data.

Most interestingly, Lucentis, the most expensive drug, and Avastin, the cheapest, have been shown to be equivalently effective in repeated randomized trials. The only difference is that Avastin is not sold in convenient doses and so must be divided up, adding another step and a very small risk of contamination.

Such variety in treatment, analysts say, calls into question whether doctors are treating patients based on the best available evidence, or other considerations. It’s not just this disease either.

The map below shows how much Medicare spends per beneficiary on drugs, such as these, that are administered in medical settings.

Steven Rich/The Washington Post