Vision Care » Cataract

Nutritional Supplementation to Prevent Cataract Formation

admin — Mon, 12 Oct 2009 22:09:18 +0000

Age-related cataract (ARC) is the leading cause of blindness in the world, particularly in developing countries. In contrast, cataract surgery has become the most frequent surgical procedure in people aged 65 years or older in the Western world, causing a considerable financial burden to the health care system.

The development of cataracts is mainly an age-related phenomenon, although socioeconomic and lifestyle factors appear to influence their development, e.g. smoking has been found to directly influence ARC. A key role in the pathomechanism of the crystalline lens alteration is played by glucose metabolism and associated effected redox potential, which may induce oxidative damages. Aldose reductase blockers were able to prevent the development of diabetic cataracts in experimental studies, however clinical trials were interrupted due to unclear side effects. Other drugs with radical scavenging properties were effective in in vitro and in vivo experiments, but could not be proven to be efficient and safe in preclinical human trials.

A number of epidemiological studies showed an increased risk of nuclear or cortical cataract in people with low blood levels of vitamin E. It is also known that the measured levels of ascorbic acid decline with increasing age in the lens. Beta-Carotin and other non-polar carotenoids seem to be missing and may therefore only play a minor role. Polarized carotenoid lutein and zeaxanthin are available in low concentrations and may therefore have some direct effects.

The results of the present interventional studies are still controversial. While the Linxian studies indicated that the prevalence for nuclear cataract was reduced by the supplementation with retinol/zinc or vitamin C/molybdenum, the AREDS trial showed no effect of the antioxidant formulation on the development or progression of ARC. Again, while the REACT study demonstrated a statistically significant positive treatment effect 2 years after treatment for the US patients and for both subgroups (US & UK) after 3 years, no effect was observed in UK patients alone.

In another US study, the Physician Health Study, no positive or negative effect of Beta-carotin was observed. Taken together, these studies suggest that any effect of antioxidants on cataract development is likely to be very small and probably is of no clinical or public health significance, thus removing a major rationale for ‘anticataract’ vitamin supplementation among health-conscious individuals.

Cataract Surgery Generally Safe

admin — Mon, 12 Oct 2009 22:05:43 +0000

Generally, cataract surgery is more prone to complications if the cataract is more advanced. The cataract becomes harder or denser as it matures, and more difficult to remove. However, the critical issue is whether the benefit of the surgery is worth the risk.

The decision to proceed with cataract surgery should be based on the person’s visual needs. When the cataract is still mild, it is certainly easier and safer to remove. However, the benefit may be low because the vision is not significantly impaired. When vision is impaired to the point that the person can no longer do activities that he or she likes or needs to do (such as drive or read), then the benefit of having the cataract removed would be high and probably worth the risk of surgery. Cataract surgery techniques have advanced enough so that the procedure is generally very safe, regardless of the severity of the cataract.

Gene Found for Age-Related Cataract

admin — Mon, 12 Oct 2009 22:03:42 +0000

A gene associated with the formation of age-related cataract, a leading cause of blindness, has been identified by scientists.

The EphA2 gene encodes an enzyme that plays a role in the repair of damaged proteins in the eye. Expression of the EphA2 gene decreases with age, which means damaged proteins can clump together and cause the eye lens to become cloudy, resulting in obscured vision, according to the study in the July 31 issue of the journal PLoS Genetics .

The international group of researchers, including a team from Case Western Reserve University in Cleveland, have identified several mutations in the EphA2 gene that are associated with age-related cataract. They plan to search for more mutations.

When Is It Time for Cataract Surgery?

admin — Mon, 12 Oct 2009 21:59:42 +0000

Almost everyone who lives a long life will develop cataracts at some point. As more Americans live into their 70s and beyond, we all need to know a few cataract basics: risks and symptoms, tips that may delay onset, and how to decide when it is time for surgery, so good vision can be restored.

August is Cataract Awareness Month, and the American Academy of Ophthalmology encourages Americans to know their risks, especially people who have diabetes, smoke, or have a family history of cataract.

“Cataract surgery is a very common procedure, with a success rate of more than 95 percent,” says Jeffrey Whitman, MD, of the Key-Whitman Eye Center in Dallas, TX, and an Academy clinical correspondent. “The eye’s natural lens with cataract is removed and replaced by an intraocular lens (IOL) , selected to meet each patient’s vision correction needs. Talk with your Eye M.D. about IOL options and related use of eyeglasses, so together you can select the best IOL for you.”

A few simple tips will help you maintain healthy vision and make the right choices if you develop a cataract.

Get a baseline exam if you’re over 40. As part of the EyeSmart campaign, the Academy and EyeCare America, a public service program of the Foundation of the American Academy of Ophthalmology, recommend that adults with no signs or risk factors for eye disease get a baseline screening exam at age 40 — the time when early signs of disease and vision changes may start to occur. During this visit your Eye M.D. (ophthalmologist) will advise you on how often to have follow-up exams. People of any age with symptoms or risks for eye disease, such as a family history, should see their Eye M.D. to determine a care and follow-up plan.

Know your risk factors. In addition to having a family history of cataract, having diabetes, or being a smoker, other factors can increase your risk of developing a cataract. These include extensive exposure to sunlight , serious eye injury or inflammation, and prolonged use of steroids, especially combined use of oral and inhaled steroids.

Reduce your risks. Use UV-rated sunglasses when outdoors and add a wide-brimmed hat when spending long hours in the midday sun. One of the best things anyone can do for their eyes and overall health is to quit smoking or never start. People with diabetes can reduce cataract risk by carefully controlling their blood sugar through diet, exercise and medications if needed.

Be informed about when to consider surgery. This decision is really up to each person based on his or her daily activities and related vision needs. The concept that the cataract is “ripe,” or ready, is no longer considered a valid reason for surgery. After age 65, most people will see their Eye M.D. at least once a year, where they will have their vision tested and learn whether cataracts are growing. But only an individual can determine whether symptoms like glare, halos, blurriness, dimmed colors or other cataract-related problems are making activities like driving and reading difficult or impossible. The Academy’s consumer guide to cataract surgery offers more information.

Talk to your Eye M.D. When preparing for surgery you will need to give your doctor your complete medical and eye health history, including especially whether you are or have taken Flomax®, Hytrin®, Uroxatral® or Cadura®. These medications can cause the iris to move out of its normal position, which can lead to complications during cataract surgery. You can still have successful surgery if your surgeon knows you have taken these drugs and adjusts his or her surgical technique.

If you have had LASIK or other laser refractive surgery, it’s important to provide your pre-surgery vision correction prescription to your Eye M.D., if possible. (The record of this prescription is also called the ” K card .”)

Dry Eyes

admin — Sun, 14 Jun 2009 21:40:48 +0000

The eye is a vital organ that converts the reflected light from an object into neuron signals and feed them to the brain for processing and identification of the object.

The eyes can suffer from various conditions such as myopia, hyperopia, conjunctivitis, cataract, astigmatism, glaucoma, sty, infection and tumors. The eyelids blink several times a minute to clean the eyes and keep them moist, using the secretion of tears from the lacrimal gland. The lids also have a fast reflex action to protect the eyes.

Tears serve an important function in the health of the eyes. They wash off dust, chemicals, germs and other foreign bodies. They control the microorganisms in the eyes with their enzymes. In a condition called ‘dry eyes,’ the tear gland does not secrete enough tears, or the quality of the liquid is poor and evaporates very fast. Normally the tears form three layers over the eye. The lacrimal glands produce water, and the small glands produce oil and mucus. The bottom mucus layer covers the cornea, and over it is the water layer with some nutrients. The outer oil layer prevents the water from evaporating.

Dry eyes are one of the old age problems, where not enough oil is produced. Some medications cause this problem. Hot, dry and windy weather can also lead to this problem. Menopause, thyroid conditions and vitamin A deficiency can also cause it. The person with dry eyes has itching, burning, irritation, blurred vision, discomfort and redness of the eyes. Surprisingly, there may be more tears secreted.

Treatment for dry eyes is planned only after finding the root cause of the problem. For old people with no specific problem, artificial tears two to three times a day and an ointment during the night can take care of the problem. The passage from the eyes to the nose, which normally drains the tears, can be plugged to keep enough tears in the eyes.

Dry eyes, if left untreated, can cause more severe problems for the eye. Drinking plenty of water, taking the eyes off of paperwork or the computer periodically, and blinking the eyelids deliberately are some of the ways we can assist our eyes.