What is a Cataract?

By Dr. Loretta Lanphier, ND, CN, HHP, CH

It can be very frustrating to run into trouble seeing or doing things that you’ve never had a problem with before. Maybe night driving is more of an eye strain than it used to be. Or perhaps you need better lighting to do common tasks than you did a few years ago. Is it just “old age” creeping up on you, or could something else be responsible? There is a possibility that you could be developing a cataract, one of the most common of all vision disorders.

What is a Cataract?

A cataract is an eye disorder that is caused by the clear lens of the eye becoming butty. Looking through a butty lens has been compared to trying to see through a frosted or fogged up window. Cataracts cause opaqueness to affect the normally crystalline clear eye lens. This can lead to reduced vision, and if left untreated, eventually to blindness. In fact, cataracts are the leading cause of impaired vision and blindness in the United States today. However, the majority of cataracts are very treatable and the prognosis for recovery is excellent for most patients.

Cataracts are so common in elderly folks, that many consider it a normal part of the aging process. Approximately 50% of Americans over the age of 65 have some degree of lens butting, and after the age of 70, the percentage goes up to about 70%.

Perhaps a little knowledge of how the eye operates will help to understand cataracts better. The human eye is composed of several different parts. The outermost layer of the eyeball includes the dome-shaped cornea, and the sclera. Both of these structures serve to protect the eye. Next comes a layer that consists of the iris (the colored part of the eye), pupil (the dark round spot in the middle of the iris), and ciliary body (location of the muscles that help the eye to focus). The pupil and iris are responsible for controlling the amount of light that comes into the eye. The lens, where cataracts form, is found behind the pupil and the iris.

The lens is normally transparent and somewhat elastic. This flexibility of the lens makes it possible for it focus on both close and far away objects. The muscles in the ciliary body are attached to the lens by ligament-like fibers called the “zonules of Zinn.” As the zonules are expanded and contracted, the lens is able to focus and provide clarity of vision. This process is known as “accommodation.” As we age, the lens progressively loses its elasticity, and initially leads to troubles with close-up vision. This occurs in most folks at about the age of 40, and is called “presbyopia.”

The lens of the eye is basically composed of about 35% protein and 65% water. As we age, the proteins of the lens begin to deteriorate, and this is the main reason for my buttiness that results in cataracts. It is similar to what happens to the clear proteins of an egg white when it is cooked. They change from transparent to an opaque white as the proteins are broken down. The structure of the lens may be thought of as a piece of fruit. The nucleus is like the pit. The cortex is the fleshy part of the fruit. The outer layer of the lens is like the skin of the fruit, and is called the capsule.

Cataracts occur in three distinct types, classified by which part of the lens they form in:

Nuclear: This type of cataract forms in the center of the lens. Some folks with nuclear cataracts experience a phenomenon called “second sight” whereby they experience a temporary improvement in their reading vision, and may even be able to read without their glasses. However, this does not last, and as the cataract advances, the lens turns progressively more yellow, and eventually may turn brown. Nuclear cataracts cause problems with night driving, seeing in dim light, and distinguishing between colors, especially blues and purples.

Cortical: Cortical cataracts start on the outer edge of the cortex. They usually begin as whitish streaks that spread towards the center of the lens and progressively impede the amount of light that is able to pass through the lens. Both near and far vision can be affected, and many patients with cortical cataracts have trouble with focusing and experience distorted vision.

Subcapsular: These typically form just under the capsule, near the rear of the lens, directly in line with the path the light takes to reach the retina. Subcapsular cataracts tend to cause problems with reading, vision in bright light, and glare or halos associated with night vision.

What Are the Symptoms of a Cataract?

Most cataracts develop slowly over time, and there is usually not any pain or discomfort associated with them. Initially, patients may not notice any change in their vision. However, as the cataract grows and butts a greater portion of the lens, some of the following symptoms may begin to appear:

  • Dim, butted, or blurry vision
  • Increasing difficulties with night vision
  • Increased sensitivity to bright lights and glare, such as oncoming headlights while driving at night
  • Poor central vision
  • Seeing halos around lights
  • Frequent changes in eyeglass or contact lens prescriptions
  • Diminished color vision (fading or yellowing)
  • Poor vision in bright sunlight
  • White milky appearance of the pupil (usually in advanced cataracts)
  • Need for better lighting while reading or doing other close work

What Causes Cataracts?

The exact reason why the lens of the eye changes as we age is not known. Initially thought of as an inevitable part of aging, scientists are beginning to rethink this assumption. There are several theories that researchers are exploring:

Free radical damage: Free radicals are substances that cause oxidative damage to tissues throughout the body. Antioxidants are naturally occurring substances found in many foods that are responsible for negating the effects of free radicals. When levels of antioxidants in the body are insufficient, cataracts are allowed to form. The good news is that many nutritionists and alternative health care providers believe that a diet high in antioxidant nutrients can prevent cataracts and even reverse the damage of existing cataracts if they are not too far advanced. Beta-carotene, found in carrots and other vegetables, is one of the best sources of antioxidants. Mom was right when she told us to eat our carrots so we could see better! Like the old joke says, You never saw a rabbit with glasses, did you? Some other suggested foods are:

  • Leafy-green vegetables
  • Yams, squash, and other yellow, deeply colored vegetables
  • Broccoli
  • Citrus fruits and a variety of dark-colored berries, such as blueberries and blackberries. These are high in vitamin C, a wonderful source of antioxidants.
  • Wheat germ oil is excellent for its vitamin E content.
  • Avoid fried, fatty or rancid foods, as they contain high amounts of free radicals
  • Smoking: Statistics show that smoking or exposure to second hand smoke will increase an individual’s risk for developing cataracts. The reasons for this are not fully understood, but it is known that tobacco smoke is a source of free radicals.
  • Excessive UV light: UV light is also recognized as a source of free radicals. A lifelong habit of wearing quality sunglasses that protect against UV light (especially UV-A and UV-B) is a great preventative step to reduce the chances of developing cataracts later in life.
  • Alcohol: Some researchers believe that alcohol may increase the exposure to antioxidants as well, and thus increase risk for cataracts. However, the evidence for this is scant.

Other risk factors that may make it more likely for you to get a cataract are:

  • Diabetes
  • Previous eye surgery
  • Previous eye injury or inflammation
  • Extended use of corticosteroid medications

How Do I Know if I Have a Cataract:

Changing vision is normal throughout our lifetimes. Regular checkups from an optometrist or an ophthalmologist are recommended every 2-4 years up till age 65, and every 1-2 years thereafter. Your doctor will routinely check for signs of a cataract during the process of an overall eye exam. Some of the tests commonly used are:

  • Visual acuity test: This is the typical eye chart exam we are all familiar with. Your eyes are tested one at a time to determine the acuity, or sharpness, of your vision. 20/20 is considered perfect acuity.
  • Slit-lamp exam: A slit lamp is basically a specially designed microscope that allows the doctor to magnify his view of the structures of your eye. The procedure utilizes a bright line or slit of light to illuminate the cornea, iris, lens, and surrounding tissues. The slit of light allows viewing of minute parts of the eye in great detail.
  • Retinal exam: This is a test that is specifically designed to check for cataracts. Dilating drops are used to keep the pupils open wide and thus provide a better view of the back of your eye. A slit-lamp may be used for this procedure or another device called an opthalmoscope. The retinal exam gives the doctor an excellent chance to thoroughly examine your lens for any signs of a cataract, as well as check for glaucoma and other eye abnormalities. If a cataract is found, it can also be determined to what extent butting has taken place. This information is helpful when deciding on appropriate treatment.

What Treatments Are Available for Cataracts?

Surgery is the only official treatment for cataracts. Some cataracts, especially if discovered early, may not require any attention. This often depends on the type and location of the cataract. It’s always a good idea to get a second opinion if cataract surgery is recommended, because it is not always necessary. Many cataracts will never develop to the point of significantly interfering with vision, or it may take many years for them to do so. Generally, cataracts are not harmful to the eye, and they will not cause damage to other tissues in the eye. Many times, eyeglasses can correct the condition, and surgery is not necessary. If you have a cataract in one eye, often the other eye will adjust and compensate for the situation. I am not against cataract surgery if it is justified. I just believe in exploring all my options before going under the knife.

If you do choose to have a cataract surgically removed, it is a relatively innocuous procedure that is usually done on an outpatient basis. In fact, cataract surgery is the most common surgical procedure performed in America today. The risk is relatively low, but be sure that your doctor takes any other eye conditions you may have into consideration. Sometimes if you have advanced glaucoma or macular degeneration, for example, the results of cataract surgery may be disappointing.

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