Clarity on cataracts

Each of our eyes comes equipped with a lens tucked behind the pupil that focuses light on the retina in the back of the eye. When we're young, those lenses are quite clear. But with age and exposure to light and other harmful factors, they have a tendency to cloud up, as the proteins in the watery mixture inside the lens clump up. Clouding of the lens is called a cataract.

Cataracts are typically small to begin with and in the center of the lens. Both lenses tend to be affected, although often one is more clouded than the other. Symptoms include blurry vision and difficulty with glare at night.

In many cases, there's an increase in nearsightedness well before there's any detectable clouding of the lens. This "myopic shift" can be treated with a new prescription for glasses or contact lenses that correct the change in vision.

Cataracts tend to get worse and, if left untreated, can result in blindness. In the poorer countries of the world, untreated cataracts are a leading cause of blindness. But elsewhere, as the lens gets cloudier and vision problems increase, surgery prevents that from happening. The procedure typically involves removing the clouded lens and replacing it with an artificial one made of clear plastic.

The lens is surrounded by a thin, envelope-like capsule. Currently, most cataract surgery involves making an incision in the capsule, using ultrasonic energy to break up the lens into small pieces, and then vacuuming those pieces out so a new artificial lens can be put back into the capsule.

Ophthalmologists have been using high-speed lasers for some time to perform the LASIK procedures that reshape the cornea so that people no longer need to wear glasses. Now some are using similar technology to perform cataract surgery. Very fast femtosecond lasers -- a femtosecond is one quadrillionth of a second -- are used to open up the capsule and to break up the lens.

Proponents say these lasers, which are guided by computers, will make cataract surgery that much safer for two reasons: The incisions are more precise, and lower levels of ultrasonic energy are needed to break up the lens because the laser softens them up. These computer-assisted lasers can make a perfectly circular incision in the capsule that his trained hand cannot match, notes Dr. Bradford J. Shingleton, an associate clinical professor at Harvard Medical School and a prominent Boston eye surgeon who specializes in cataracts.

But, so far, these are just claims without a great deal of quality evidence to back them, and nothing remotely close to the results from a large, well-designed clinical trial that would be definitive. Still, Shingleton says laser surgery could potentially be one of those technologies that sweeps away old techniques and the equipment used to perform them.

One question, though, is whether the technical improvements in the operation will translate into significantly better outcomes. There isn't that much room for improvement, Shingleton says. "You are taking an A-plus operation and maybe making it an A-plus-plus operation."

But say there are better outcomes. Then the question becomes whether they are worth the additional cost. How much pricier the laser cataract surgery will be than conventional cataract surgery is hard to say at this point. But the laser setups are expensive, and the ophthalmology practices that buy them will have to recoup their investment.

Another big unknown is whether Medicare and other insurance will provide coverage. Right now, surgeons can't charge Medicare extra for doing cataract surgery with a laser. Until they can, laser cataract surgery may be slow to catch on.

Once cataract-damaged lenses are removed, several different types of artificial ones can be used to replace them. Here are some of the choices:

Monofocal lenses are the least expensive choice among the lenses. Medicare pays for cataract surgery, but caps coverage of the lenses; only monofocal lenses are fully covered.

Cost is an issue, also. A Crystalens lens is between $2,000 and $3,000 more expensive than a monofocal lens, and Medicare doesn't cover the additional expense.

Reducing your risk of getting cataracts

Age is the main risk factor, so the possibility of getting cataracts is one of the relatively small prices we pay for long life. Still, there are several things you can do to reduce your cataract risk.

1. Don't smoke -- and quit if you do. Smoking doubles the chances of getting a cataract. If you quit, the risk declines, but it may never disappear altogether.

2. Watch your alcohol consumption. Alcohol consumption slightly increases the risk of cataract, and the more you drink, the greater the risk. Swedish researchers found that women who had one or more alcoholic drinks a day were about 11 percent more likely than nondrinkers to need cataract surgery, and they needed surgery about two years earlier.

3. Protect your eyes from sunlight. Exposing your eyes to ultraviolet B (UVB) light, the part of the light spectrum that causes sunburn, increases the risk of developing cataracts. Sunglasses block UVB and, generally speaking, the darker the lens, the more UVB it blocks. Wearing a brimmed hat also will help protect your eyes from UVB light.

4. Eat plenty of fruit and vegetables. Theoretically, vitamins and minerals with antioxidant properties should protect against cataracts, but the results from studies of supplements aren't persuasive. Lutein and zeaxanthin, carotenoids found in leafy green vegetables (kale, spinach, collard greens) and egg yolks, may be associated with decreased risk for cataracts, although the evidence is stronger for a protective effect against macular degeneration, another age-related eye disease. Several studies have suggested that the risk of cataracts is reduced by a healthful diet, with plenty of fruit and vegetables.