The Baltimore Orioles have an unlikely secret weapon this season: Brian Roberts's contact lenses.

Mr. Roberts, a second baseman who leads the American League in hitting, has been testing a new type of prescription contacts developed jointly by Nike Inc. and eye-care-products maker Bausch & Lomb Inc. The tinted contacts, which give Mr. Roberts a devilish red-eyed appearance, function much like sunglasses by cutting down on glare.

The sporting-goods industry has cranked out a steady stream of technologically advanced goods, such as carbon-composite racing bikes, that are quickly snapped up by weekend warriors happy to shell out for the same gear that the pros use.

Nike's $20 tinted lenses, which go on sale next month, are the latest entry in this $104.7 billion market. They are targeting athletes in sports such as golf, tennis and soccer who have been reluctant to use sunglasses because of fogging, scratching or the simple annoyance of wearing eyeglasses.

The lenses require a prescription and fitting by an eye doctor, even for those with 20/20 vision. About half of the athletes who have worn the lenses have never worn corrective eyeglasses or contact lenses before, the company says.

Eyes are becoming the latest frontier in competitive sports. Golfers Tiger Woods and Laura Davies are two of dozens of athletes who underwent laser surgery to improve their vision. Many other athletes routinely incorporate eye-training exercises into their workouts. Wholesale shipments of sports-eyewear products, such as eyeglasses and goggles, jumped 19 percent to $600 million in 2003 from $505 million in 2000, according to the Sporting Goods Manufacturers Association.

Sport-sunglasses makers including Oakley Inc. have long used similar technology embedded in their glass lenses. Versions of the lenses can correct short- and far-sightedness. People with astigmatisms, or oblong-shaped eyes, should consult with their doctors because the Nike lenses haven't been developed specifically for astigmatism.

The tinted lenses aren't recommended for use at night or while driving. They may also irritate the eyes of those who have never worn contacts before. "I wouldn't rule out the potential for improvement but sports performance is a complex issue," says John Corzine, chief of contact lenses at the University of California, Berkeley, School of Optometry.

Nike's MaxSight Sport-Tinted Contact Lenses will sell for about $20 a pair. Nike says a red-colored version cuts blue light to make a fast-moving ball stand out more clearly. A green-colored pair enhances red and green light to help a golfer better see the slope of a putting green.

"When I first put them on, it was the last day of spring training and it was bright and sunny, and it was just perfect because guys at the plate couldn't see anything when they were hitting," Mr. Roberts wrote in an email. "They would come back from the dugout saying, 'I can't see!' and that day I went 3 for 3."

Recently the sports-eyeglasses market has been heating up. Oakley has pushed into the electronics arena with its Thump combination sunglasses and MP3 player. Its price tag -- $395 to $495 -- is among the highest in the industry. It has sold more than 90,000 pairs since its launch in November. Later this year Oakley will partner with Motorola Inc. to market the RAZRwire, a hands-free, wireless headset attached to a pair of sunglasses.

For Bausch & Lomb and eye doctors, the contacts are a chance to broaden sales. Initially, sales will be limited to about 350 optometrists and ophthalmologists, some of whom will listed on the company's and a Nike Web site.

Next year, the two companies plan to allow replacement-lens sales through a larger group of eye-care specialists, and through Internet sites and mail-order companies, broadening sales to about 10,000 outlets.

MaxSight lenses are designed for daily wear and will last about a month, the companies say. Bausch & Lomb and Nike expect to sell a $60 package with three pairs of lenses, a mirror for inserting the lenses, solution, rewetting drops and carrying case.

Nike is also introducing high-contrast balls that are designed to be more easily picked up by the lenses' filtering optics. Nike already has rolled out several products developed by the sport-vision team responsible for MaxSight. Its Total 90 Aerow Hi-Vis soccer ball is meant to be used in low-light conditions. The Total 90 balls have been used in the English Premier League and Spanish Primera Liga.

Optometrists are excited about the prospects. Kelly Kerksick, a Columbia, Ill., optometrist who expects to sell the lenses, already has nearly 80 customers awaiting their release, including two Professional Golfers Association of America members and several high-school students. Dr. Kerksick will recommend the amber-tinted lenses to shotgun and bow-hunters, whose season starts as early as October.

One of those on her waiting list is Christopher Dyroff, a football running back at nearby Waterloo High School.

"We're the smallest school in our conference," he says. "If it makes me see clearer, it may help my awareness on the field." At the least, the lenses could give him an edge over other players, he says. The amber lenses that Dr. Kerksick recommends makes the wearer's eyes turn bright red, he says, which is "cool, because that's my favorite color."