Once upon a time, a baby wearing sunglasses was merely a chance for a cute snapshot. Now, some eye doctors say parents should start putting sunglasses on babies as young as 9 months to protect their eyes. The cumulative effect of the sun's damaging ultraviolet rays can cause early cataracts, these experts say.

Other eye doctors are skeptical, saying no medical studies link childhood sun exposure to later eye disease.

But makers of sunglasses aren't waiting around for more research. Foster Grant, Julbo and Baby Banz have designed sunglasses ($15 to $30 per pair) with wraparound straps to keep them on a little one's head. The frames come in pink, blue and dozens of other colors and patterns.

Dr. Nathalie Azar, a pediatric ophthalmologist at University of Illinois Chicago, applauds the products and encourages parents to start sunglasses young.

"The sooner you do it, the better. If kids get into the habit, they can learn to keep sunglasses on," says Azar, who is working with the Lions Club International on a campaign to get kids to wear sunglasses.

Dr. Richard Lewis, professor of ophthalmology at Baylor College of Medicine in Houston, says there's only suggestive evidence of harm. For example, people who live at high altitudes and don't wear sunglasses are more prone to cataracts than people at lower altitudes. He doesn't push sunglasses for babies. He says, "Is it an OK idea? Sure. Is there good rational scientific proof? No."

Weighing the evidence, many parents will decide to err on the side of caution. Here are some tips from the American Academy of Ophthamology for protecting babies' and children's eyes: