Drugs linked to cataracts, behaviors can delay them

The bad news: Commonly used drugs known to make people more sensitive to sunlight may slightly increase the risk of a certain kind of cataract, according to a new study.

The good news: Eating a healthy diet loaded with fruits and vegetables may delay the development of cataracts, according to another study out this week.

Cataracts, in which a clear lens becomes cloudy, are the leading cause of impaired vision. More than half of all aged 75 or older Americans have a cataract or have had cataract surgery. The first symptoms may be difficulty seeing at night followed by increasingly blurred and dimmed vision.

Earlier research by Dr. Barbara Klein and colleagues had shown that certain “sun-sensitizing” medications might be linked to cataracts in men. To see if this was true in all people, the University of Wisconsin School of Medicine eye specialist and her colleagues analyzed the medical records of 2119 patients followed over 15 years.

They found that for varying levels of sunlight exposure, people who used a number of drugs including the painkiller naproxen, the diabetes drug glyburide, the antibiotic ciprofloxacin, the antidepressant amitriptyline, and the blood pressure medication hydrochlorothiazide had about a 26 percent chance of developing a condition known as a cortical cataract.

That compared to about 22 percent of those who did not use these medications, they report in the August issue of the Archives of Ophthalmology. The drugs were not tied to two other types of cataracts.

Still, Klein was reluctant to make too much of the results. “I don’t want to scare the pants off people,” she told Reuters Health when asked if the data warranted warning about cataract risks with the use of these drugs and sun exposure.

Much more research has to be done to meticulously measure drug dosage and duration and sun exposures before definitive conclusions can be drawn, she cautioned.

In the other study, Julie Mares, of the University of Wisconsin in Madison, and colleagues wanted to know if eating a healthy diet might protect against cataract formation. “Nothing so far has been discovered that can prevent cataracts; they are a natural consequence of aging,” Mares told Reuters Health.

Delaying cataracts in an increasingly aging population could reduce a significant burden on the healthcare system, Mares and colleagues write in the June issue of the Archives of Ophthalmology after finding a healthy diet may delay cataracts at least 2 and a half years.

While the biggest risk for getting cataracts is getting older, smoking is the most common “modifiable” risk factor reported in population studies. Sun exposure and poor diets have also been associated with increased risk but previous research on diets has usually focus on a limited number of vitamins or minerals at a time.

The researchers analyzed data from 1808 women enrolled in the Women’s Health Initiative Observational Study for an association between eating a healthy diet and the development of cataracts.

The women, all aged 50 to 79, answered questions about their diets, supplement use, smoking, exercise, and other behaviors. They also underwent eye exams.

Cataracts were common in the women and occurred more often as they got older. Overall, 41 percent of the women (736) had evidence of cataract severe enough to warrant surgery in at least one eye or reported having had cataract surgery.

After taking age, smoking, and other factors into account, researchers found the women who ate the diets highest in fruits and vegetables and lowest in fats had a 37 percent lower risk of cataracts than women in the study who ate less healthy diets.

By another measure, “if you take two women of the same age, the woman with the lowest healthy diet score would be about 1 and a half times more likely to have a cataract at any given age,” Mares said.

The authors conclude that eating a healthy diet along with avoiding obesity and smoking “may substantially lower the need for and economic burden of cataract surgery in aging American women.”

The study doesn’t directly prove cause and effect, “but so many arrows point in this direction that sometimes we don’t need clinical trials to hit us over the head to suggest that small changes we do on a day-to-day basis can have a large impact on our health in the future,” Mares said.

The “more than half” of Americans who have cataracts or have had surgery for them “might be cut to roughly 40%—or 40 rather than 50 of every 100 Americans—if those of us with poorer than average diets ate healthy diets; and cut further still if we did not smoke,” Mares said.

Despite the limitations of her study of drugs and sun exposure, the other study’s finding that diet might prevent some cataracts is “exciting,” Klein said.

“Anything you can do to delay putting a knife in someone’s eye is a good thing,” Klein said.

SOURCE: http://archopht.ama-assn.org/cgi/content/short/128/6/738  Archives of Ophthalmology, June and August 2010.