WASHINGTON (AP) - Glaucoma sufferers are about to get two new medicines to help fend off blindness - including one that seems to work particularly well for black patients, who are at special risk.

Both Travatan and Lumigan work by draining fluid buildup that is the hallmark of glaucoma. The Food and Drug Administration approved them Friday, saying both work equally well and thus offer an alternative to standard therapies.

But Travatan comes with an added marketing boost: A study found it worked best in black glaucoma sufferers, making it the first treatment allowed to target a group especially hard-hit by that disease.

Glaucoma is the nation's second-leading cause of blindness, afflicting some 3 million Americans and blinding about 80,000 of them a year. Black Americans are four times more likely than whites to suffer glaucoma; it typically strikes them at younger ages; and they go blind faster.

Glaucoma patients suffer a painless but dangerous buildup of pressure within the eyeball that eventually damages the delicate optic nerve until they begin losing sight. The most common form usually occurs after age 40. Treatment, including medication and surgery, can stall the disease's progression but any vision loss is permanent.

Standard first-line therapy is timolol, an eyedrop that makes the eye produce less fluid, thus reducing pressure. But it has numerous side effects and people with heart or respiratory problems cannot use it.

A second therapy, the drug latanoprost or Xalatan, is based on the natural chemical prostaglandin, which helps the eye drain off fluid. The two new drugs work the same way, the first competitors for Xalatan.

All three prostaglandin-based eyedrops effectively drop patients' eye pressure, said FDA ophthalmology chief Dr. Wiley Chambers. They also cause similar side effects, including sometimes turning blue or green eyes brown. Nobody yet knows if that's just a cosmetic side effect, or if the changing color signals some additional eye damage, he cautioned.

But eye color difference may play yet another role: Some drugs bind to eye pigment differently than others, Chambers explained, saying doctors have long known that timolol works better in light-colored eyes than dark ones.

Travatan's maker studied 600 patients who took either Travatan, Xalatan or timolol, including some 50 black patients in each drug group. After a year of treatment, 65 percent of blacks had significantly lower eye pressure vs. 51 percent of non-blacks, said manufacturer Alcon Universal Ltd.

There was no racial difference for Xalatan, which helped between 44 and 47 percent of patients, Alcon said. Timolol helped 30 percent of blacks and 37 percent of non-blacks.

Neither Lumigan nor Xalatan have been adequately studied for racial differences, Chambers cautioned. But meanwhile, the FDA is letting Alcon advertise Travatan's benefit to black patients.

Both prescription-only new drugs should be in pharmacies within a few weeks. Travatan, known chemically as travoprost, will cost about $38 wholesale for a month's supply, said Ft. Worth, Texas-based Alcon. Irvine, Calif.-based Allergan Inc. refused to reveal the price for its Lumigan, known chemically as bimatoprost.

On the Net:

FDA: http://www.fda.gov

Alcon: http://www.alconlabs.com

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