Some conditions of the eye are unfortunately a part of aging. The development of cataracts is one such condition. In fact, people between the ages of 52 and 64 have a 50% chance of developing cataracts. By age 75 the majority of people have a cataract, and 50% of all people between 75 and 85 have suffered some loss of vision as a result. Over the years, many have simply accepted this vision loss as a part of aging, but with contemporary surgical techniques and recent advances in lens implants, there is no longer a need for a person who develops a cataract in one or both eyes to simply settle for lost vision. In the United States, cataract surgery is the most commonly performed therapeutic procedure on people 65 years and older.
What is a Cataract?
A cataract is a clouding of the normally clear lens of the eye. It is not a tumor or a new growth of skin or tissue over the eye, but a fogging of the lens itself. When a cataract develops, the lens becomes cloudy like a frosted window and may cause a blurring of vision. The lens is located behind the pupil and iris (the black and colored parts of the eye). The lens is composed of three parts, the capsule, the nucleus, and the cortex. The capsule surrounds the cortex, which surrounds the nucleus, or center of the lens. If you picture the lens as a peach, the capsule is the skin, the cortex is the fleshy fruit, and the nucleus is the pit or seed. See anatomy for more about the parts of the eye. The lens exists to focus light on the retina at the back of the eye in order to produce a sharp image. When a cataract forms, the lens can become so opaque and unclear that light cannot easily be transmitted to the retina. Often, however, a cataract covers only a small part of the lens, and if sight is not greatly impaired, there is no need to remove the cataract. If a large portion of the lens becomes cloudy, however, sight can be significantly reduced until the cataract is removed.
Causes and Symptoms
There are many types of cataracts. Most cataracts are caused by a change in the chemical composition of the lens, resulting in a loss of lens transparency. These changes can be caused by aging, eye injuries, certain diseases and conditions of the eye and body, certain medications (especially steroids), and hereditary or birth defects. If and when the normal process of aging causes the lens to harden and turn cloudy, they are called senile cataracts. These are the most common type. They can occur as early as age 40. Children are not impervious to cataracts either. When cataracts appear in children, they are sometimes inherited. They can also be caused by an infection or inflammation during pregnancy which affects the unborn baby. This latter type of cataract is called congenital, meaning present at birth. Eye injuries can cause cataracts in people of any age. A hard blow, puncture, cut, chemical burn, or rarely, extreme heat can damage the lens and result in what is called a traumatic cataract. Depending on the size and location of the cloudy areas in a lens, a person may or may not be aware that a cataract is developing. If the cataract is located on the outer edge of the lens, no change in vision may be noticed. If the cloudiness is located near the center of the lens, it usually interferes with clear sight. Common symptoms experienced with developing cataracts include blurred or double vision, sensitivity to light and glare which make driving difficult, less vivid perception of color, and frequent eyeglass prescription changes. As the cataract grows worse, stronger glasses will no longer improve sight. The pupil, which normally appears black, may undergo noticeable color changes and appear to be yellowish or white.
Detection and Diagnosis
Usually, cataracts cannot be viewed from the outside of the eye without proper instruments. If blurred vision or other symptoms are noticed, an eye physician should be visited as soon as possible for an examination. The eye physician examines the lens of the eye with a variety of instruments to determine the type, size, and location of the cataract. The interior of the eye is also viewed with an instrument called an ophthalmoscope to determine if there are any other eye disorders contributing to the blurred vision.
Treatment
Usually, cataracts cannot be viewed from the outside of the eye without proper instruments. If blurred vision or other symptoms are noticed, an eye physician should be visited as soon as possible for an examination. The eye physician examines the lens of the eye with a variety of instruments to determine the type, size, and location of the cataract. The interior of the eye is also viewed with an instrument called an ophthalmoscope to determine if there are any other eye disorders contributing to the blurred vision. When cataracts cause enough loss of sight to interfere with a person’s work, hobbies or lifestyle, it is probably time to remove them. Depending on individual needs, the patient and the ophthalmologist decide together when removal is necessary. Surgery, which can be performed under local anesthesia, is the only effective way to remove the cloudy lens from the eye. Fortunately, cataract surgery is highly successful and over 90% of patients who undergo surgery regain useful vision. It is important to understand that complications, like infection or loss of vision, can occur during or after surgery. In any surgery, a good result cannot be guaranteed. Once the cloudy, natural lens of the eye is removed, the patient needs a substitute lens to focus the eye. These include:Intraocular lenses (IOLs) – permanent lenses implanted inside the eye during the cataract surgery; Cataract glasses – thinner and lighter than they used to be, but still thicker than most ordinary glasses; Hard or soft contact lenses – these can be worn all day, but are taken out at night; Special extended-wear soft contact lenses – appropriate for longer wear. Although the intraocular lens is by far the most popular choice, there are advantages and disadvantages to each type of lens replacement. An ophthalmologist helps the patient decide which lens or combination of lenses is best suited to their lifestyle and eye health.
Loss of sight is largely treatable or preventable
If you notice any of the cataract symptoms noted above, consult an ophthalmologist as soon as possible. Since cataracts most often form as a result of aging, individuals over the age of 40 with a family history of cataracts should have their eyes checked periodically. Though doctors have yet to find the cause or a way to prevent cataract development, over-exposure to bright sunlight has been found to contribute to development of cataracts. Wearing sunglasses with a high level of protection from ultra-violet rays or a hat with a wide brim while spending time in the sun may slow cataract growth. Though cataracts may be an inevitable problem in your life, they do not need to inevitably cause permanent loss of vision. Current surgical techniques are extremely reliable and successful, with 90% of all patients recovering at least some vision
