The federal Food and Drug Administration approved Friday the first drug that improves vision in Americans with the most common cause of vision loss after age 60.

Lucentis treats people in early stages of one type of age-related macular degeneration, the so-called wet form of AMD.

The drug will be available this week, at $1,950 a dose.

Medicare, which covers 87 percent of people who need the drug, is likely to pay for it, leaving patients with a $50 co pay, said Dawn Kalmar, spokeswoman for Genentech Inc., the manufacturer. The company provides drugs free to uninsured people with incomes of less than $75,000 a year, she said.

Ophthalmologists viewed the drug as a breakthrough.

"It will immediately become the most effective treatment we have for wet AMD," said Dr. Mark Johnson, professor of ophthalmology and visual sciences at the University of Michigan's Kellogg Eye Center. "And for the first time the average patient being treated can be expected to experience an improvement in vision, rather than reduction in the rate of vision loss."

A metro Detroit woman whose vision improved significantly after three treatments called it a miracle.

"It's absolutely wonderful," said Audra Harrington, 83. "I couldn't keep my checkbook, couldn't read, I could hardly see the television."

She's back to those activities and more.

An estimated 170,000 people have wet AMD. The number is growing with the aging of the U.S. population. AMD leads to the loss of central vision, making people unable to drive, read or recognize faces.

About 90 percent of people with AMD have the less treatable dry form. For them, diagnosis is depressing because treatments are limited, said Dr. Lylas Mogk, a Henry Ford Health System ophthalmologist and author of "Macular Degeneration: The Complete Guide to Saving and Maximizing Your Sight." (Ballantine Books, $15.95).

The drug is delivered by tiny injections into the eye, given monthly and typically for five to seven treatments, Genentech's Kalmar said. Patients get medicines so they don't feel any pain, said Dr. George Williams, chairman of ophthalmology at Beaumont Hospital in Royal Oak, Mich. Both Beaumont and U-M were among 100 medical centers that helped test the drug.

People who got the drug in the early stages of the disease had the best vision improvements, helping them return to driving or reading, Williams said. The drug does not benefit patients who have progressed to stages of the disease where scars form inside the eye, a process that occurs in as little as three to six months or over a year or more, Williams and Johnson said.