All About Cataracts

Five-year results from NASA’s Study of Cataracts in Astronauts (NASCA) suggest that exposure to solar ultraviolet radiation in space accelerates cataract progression, though the effect was small and varied with different types of cataract.

Solar UV radiation in space may increase astronauts' risk for cataracts.

Leo T. Chylack Jr., MD, reported the results of the study at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO). Dr. Chylack is clinical professor of ophthalmology at Harvard Medical School and one of the study’s investigators.

The researchers compared the rate of cataract progression in U.S. astronauts who had flown at least one space mission with that of control groups without exposure to UV radiation in space.

Though the study was limited by the number of astronauts completing the study and other factors, the five-year NASCA outcomes suggest that astronauts may experience cataract progression on prolonged space missions, according to Dr. Chylack.

He cautioned, however, that further study is needed to better understand the effects of space radiation exposure on the development and progression of cataracts.

Resource: NASA studies cataract in astronauts. Ophthalmology Times. September 1, 2010.

Smoking is associated with increased risk of cataracts among Malaysian adults, with nearly 20 percent of nuclear cataracts in Malay men attributable to smoking.

Smoking increases cataract risk, study finds.

That’s the conclusion of a new study published in this month’s issue of Archives of Ophthalmology.

Researchers in Singapore evaluated 2,927 Malaysian adults ages 40 to 80 who underwent comprehensive eye exams that included lens photographs. Among this study population, 1,338 (45.7 percent) had cataracts.

After adjusting for age, sex and other factors, current smokers were 48 percent more likely to have cataracts. The association between smoking and cataracts was strongest for nuclear cataracts; current smokers were twice as likely as nonsmokers to have this type of cataract.

Nuclear cataracts are the most common type of cataracts associated with aging. These opacities develop in the center of the lens and initially can induce myopia, resulting in a temporary improvement in reading vision sometimes referred to as “second sight.” Unfortunately, “second sight” disappears as the cataract continues to grow.

Among the study participants, 43.5 percent of men currently smoked, compared with only 3.2 percent of women.

Analysis of the study data also revealed that two indicators of low socioeconomic status — low education and low monthly income — also were associated with greater risk for nuclear cataracts in this sample population.

August is Cataract Awareness Month, and to mark the occasion the American Academy of Ophthalmology (AAO) recently issued the following tips to help consumers maintain healthy vision and make the right choices when cataracts develop:

When cataracts interfere with daily activities, it's time to consider surgery.

• Have an eye exam if you are over age 40. Advancing age is a risk factor for cataracts and other eye problems. Based on the findings of your exam, your eye doctor will advise you how often you should have your eyes examined in the future.

• Know the risk factors for cataracts. In addition to advancing age, risk factors for cataracts include smoking, extensive exposure to the sun’s harmful UV rays, a history of a serious eye injury or inflammation, having diabetes, prolonged used of steroid medications and a family history of cataracts.

• Know how to reduce your cataract risk. A healthy diet, exercise, maintaining control of your blood sugar if you have diabetes, avoiding smoking and protecting your eyes from the sun’s harmful rays with UV-blocking sunglasses and a wide-brimmed hat may help reduce your risk of cataracts.

• Evaluate how cataracts affect your life. If you have cataracts, the decision when to have cataract surgery should be based on your daily activities and how much interference your cataracts are causing. If you are noticing blurred vision, glare, halos, reduced color perception or other cataract-related problems when driving or performing other daily activities, it’s time to consider surgery.

The AAO offers additional information about cataracts and cataract surgery at its EyeSmart consumer website.

Statin medications — such as Zocor, Lipitor, Lescol, Pravachol and Crestor — used to lower cholesterol and prevent cardiovascular disease may have a side effect of increasing the risk of cataracts.

That’s the finding of a large study of adult men and women published recently in British Medical Journal. Researchers studied more than 2 million patients at 368 general practices in England and Wales. All patients were between the ages of 30 and 84, and 225,922 (10.7 percent) were new users of statins.

The objective of the study was to quantify unintended effects of the use of statin medications, according to type, dose and duration of use.

The researchers found that each statin studied was associated with an increased risk of cataract in both men and women (apart from Leschol in men due to the small number of men in the study taking this medication).

The mean increased risk of cataract formation ranged from from 25 percent to 56 percent among male and female patients being treated with Zocor, Lipitor, Pravachol and Crestor.

A direct comparison test showed no significant difference between the effects of individual statins in men or in women, and there was no evidence of greater risk of cataract with higher doses compared with lower doses.

Risk of cataract was significantly increased within one year of starting statin treatment, persisted during treatment, and returned to normal within the first year after stopping treatment.

The results of this study suggest patients taken statins should be proactively monitored for cataract formation with routine eye exams by an optometrist or ophthalmologist.

The outcomes of this study contradict results of a previous Israeli study that found statins may reduce cataract risk among men and women age 45 to 54.

SOURCE:  Unintended effects of statins in men and women in England and Wales: population based cohort study using the QResearch database. British Medical Journal (BMJ). May 20, 2010.