The lens in your eye is normally clear and enables you to see clearly. When the lens becomes clouded with a cataract the world is like a photo you didn't focus properly — everything is fuzzy and indistinct.
Cataracts are the most common cause of vision loss and blindness. In the U.S. alone, more than 20 million people over 40 either have a cataract or have had cataract surgery. They develop over a period of years or decades and can be inherited or caused by an injury or caused by damage accumulated over time. The main treatment for cataracts is to remove them through surgery. There are two main surgical procedures used for this, each of them involving removing the lens and replacing it with an artificial substitute. Both of these surgeries are relatively safe and effective.
These powerful protective mechanisms can be damaged by traumatic injury and by the effects of aging, particularly in those over 50. Aging can create a buildup in the lens of oxidized proteins and lipids (i.e., fat cells). It can also cause antioxidants to become become depleted, which in time leads to the formation of a barrier between the outer layers and the core of the lens.This is the first step in the development of cataracts, called by the ancient Egyptians, "darkening of the pupil" and "white disease of the eye."
Cataracts are the most common cause of vision loss and blindness. In the U.S. alone, more than 20 million people over 40 either have a cataract or have had cataract surgery.
Congenital cataracts are caused by genetic mutations that take place before birth, in the developing fetus. The genes that cause hereditary cataracts have recently been mapped and identified. Increasing knowledge of the genetics underlying cataracts may also help us better understand the role played by environmental and nutritional factors.
As mentioned above, the eye does have ways of protecting itself against oxidation, including deploying its own antioxidants. This is why many people develop cataracts late in life or not at all. Remarkably, some people seem to be almost entirely protected from lens oxidation. For these lucky few, there is no significant oxidation of the proteins in the center of the lens with advancing age, even past age 80.
Aging makes the eye vulnerable to processes called oxidation and oxidative stress, which damage the proteins in the lens and impair the lens's ability to protect itself.
There are three major types of human age-related cataracts; their technical names are nuclear, cortical and posterior subcapsular, the first two being the most common.
Fiber-based cataracts are further divided into two categories, called sutural and non-sutural. The latter are usually congenital and run in families.
A good guideline to use in deciding whether or not to have cataract surgery is to ask yourself if your vision loss is getting in the way of everyday activities such as driving, reading or watching TV. If the answer is yes, you should speak with your doctor or eye care professional. After talking through the benefits and risks of surgery, you will be able to make an informed decision about whether cataract surgery is the way to go. In most cases, there is no great rush; waiting to have the surgery will not affect the eventual outcome.
An exception to this rule is cataracts that interfere with the treatment of another eye problem, such as age-related macular degeneration or diabetic retinopathy. In this case, you may have to have cataract surgery sooner than would be justified by your symptoms alone.
Remember that not all cataracts need to be operated on.
If you need cataract surgery in both eyes, each eye will be done separately, usually four to eight weeks apart.
- Phacoemulsification: A small incision is made on the side of the cornea, the clear covering on the front of the eye. The surgeon inserts a tiny probe. The probe uses ultrasound waves to soften and break up the lens so that it can be removed by suction. Most cataract surgery today is done this way.
- Extracapsular surgery: The surgeon makes a long incision on the side of the cornea and removes the cloudy core of the lens. The rest is removed by suction.
Like any surgery, cataract surgery carries risks, such as infection and bleeding. After surgery, it is extremely important to keep your eye clean, wash your hands before touching your eye, and use prescribed medications to avoid infection. Serious infection can cause loss of vision or even blindness.
After surgery, it is extremely important to keep your eye clean, wash your hands before touching your eye, and use prescribed medications to avoid infection.
Despite these risks, cataract surgery is one of the most common operations performed in the United States. It also is one of the safest and most effective. 90 percent of people who have cataract surgery will see improvement in their vision.
A cataract operation usually takes less than an hour and is virtually painless. Many people need little or no anesthesia, other than enough to numb the nerves in and around the eye.
After the operation, you will be watched for a few hours for bleeding or other problems. Most people who have cataract surgery go home the same day.
However, even the most potent antioxidants cannot actually cure a cataract. And the science on the effectiveness of supplements is inconclusive. Recently, the FDA concluded that no firm proof exists for health claims about the intake of lutein or zeaxanthin. Another study concluded that a multivitamin-multimineral supplement with a combination of vitamin C, vitamin E, beta-carotene and zinc (with cupric oxide) is effective in reducing the risk of cancer, but does not recommend it for cataracts. On the other hand, there is certainly no down side to eating a healthy diet with lots of green vegetables.
So, what can we do if we are concerned about age-related cataracts? A healthy diet and common sense about sun exposure (wear sunglasses and a hat with a brim to block ultraviolet sunlight) seem to be the best bet to delay or prevent cataracts.
We can expect to see better methods of cataract prevention and therapy in the near future as we learn more about how to protect the machinery of the lens from damage from oxidation, injury, toxicity and other factors and how to correct genetic defects. In the meantime, the best weapons we have today in the battle against cataracts are: taking antioxidants either in the form of antioxidant rich food or in the form of supplements; cautious use of steroids and other drugs; and improved eye surgery.