A cataract is defined as a cloudiness or haziness of the lens of the eye, which is usually crystal clear. It is like looking out of a fogged up window. Cataracts usually do not cause pain or double vision. The view of which someone with cataract sees makes it hard to read, write, drive, and see the expressions on other peoples faces, seeing “ghost” visions, changes in colors, sensitivity to light and glare, and poor distance vision. When these symptoms are present, you need to look into surgery. The cataract may start as a blurring in one area of the eye, which will not affect the eyesight. As the cataract develops and the cloudiness gets worse, it will affect eyesight as listed above. Also, as the cataract develops, the lens will develop a yellowish, greenish, or brownish tent. This tent is what effects colors such as blacks and purples. If the lens turns completely white, which is rare, it is called an overripe or hypermature cataract. It can cause inflammation, pain, and headache, and needs to be removed as soon as possible.
Cataracts are most common in older adults, usually after age 65, but as early as age 40. By the age of 80, more than half of all Americans will have had a cataract or had cataract surgery. More than 1.5 million cataract surgeries are preformed each year. It is the leading cause of blindness. When someone’s eyes work properly, light passes through the cornea and the pupil to the lens. The lens then focuses the light. When the lens becomes clouded, the passage of light is clouded, thus reducing the person’s ability to see. The cloudiness is caused by clumping of the protein fibers that make up the lens. This clumping occurs naturally with aging as the cells die.
One reason why the lenses change with age is from free radicals, two sources of free radicals are smoking and UV light. Smokers have a greater chance of getting cataracts than do non-smokers. Diseases such as Diabetes can contribute to cataracts, as can physical injuries such as puncture wounds to the eye, chemicals and intense heat. Metabolic disorders also contribute to the formation of cataracts, as can a family history. If a pregnant mother contracts rubella during pregnancy, cataracts can develop in the unborn child during childhood.
Cataracts can take years to form, or they may form in a few months. It’s different for every person. Cataracts may develop in both eyes, although the development of the cataract may be different for each eye. It doesn’t affect the eyesight at first, but as it continues to form it will interfere with eyesight. Cataracts will not go away on its own or with medication, the only way to get rid of it is to have surgery.
Cataracts may occur three types: nuclear, cortical, and subcapsular. With nuclear cataracts, the cloudiness occurs in the middle of the lens. The lens will start to change the way it focuses light, and you will become nearsighted and there is a possibility that vision will actually improve for a short time. This improvement will reverse as the lens becomes tinted. Seeing in dim light and nighttime driving will be especially hard.
In cortical cataracts, the cloudiness will be in the form of streaks on the outer edges of the lens. The streaks will eventually move into the center of the lens, which will interfere with the amount of light that reaches the lens. You will have problems with distance vision as well as near vision, focusing, distortion, glare and the loss of contrast.
Subcapsular cataract forms in the back of the lens, under the capsule shell, blocking the passage of light. It may form in both eyes, but advances more in only one eye. Subcapsular cataract interferes with reading, reduces vision in bright light, and causes halos and glares.
The cataract can be diagnosed through an eye exam, which includes three tests; the visual acuity test, the tonometry exam, the retinal exam, and the slit-lamp examination. During the visual acuity examination, the optometrist will test each eye to determine how well you are able to see at different distances. While taking this examination, you cover one eye while reading letters with the other eye. The letters progressively get smaller, and this lets the doctor know how well you see.
During the tonometry examination, the doctor will measure the amount of pressure within the eye, often using numbing drops for pain.
During the retinal examination, dilating drops are administered to open the pupils, making the back of the eye more visible. By using the slit-lamp, the eye doctor can determine if there is a cataract present, and the amount of density in the clouding of the lens.
If you are diagnosed as having a cataract, there are no pills, diets, or exercises, which will prevent the cataract from progressing. In the early stages there are a few things that you can do to help with your vision, these include the accurate prescription for your eyeglasses or contacts, using a magnifying glass while reading, limit driving at night, improve the lighting in your home, and wear sunglasses outside. Some people are able to use eye drops that widen the pupil of the eye, the drops will only work if the cataract is located near the back of the lens and also if it is small. As the cataract progresses, these tools will start to become more ineffective and you may need surgery. Surgery used to remove the cataract is only needed when everyday activities become impossible to perform, such as reading, driving, or even watching television. And is also based on such factors as lifestyle, age, and occupation. More than 95 percent of the people who have the cataract surgery have no complications, and actually recover having better vision than they did before.
If cataract surgery is the right thing for you, then before surgery your surgeon will measure the size and shape of your eye. This is measured using ultrasound, which is painless. The cataract surgery is an outpatient procedure, started on one eye only. Surgery on the other eye may not be needed, but if you decide to get surgery on the other eye you will have to wait a few months.
There are two different methods used to remove the cataract. The first is called Phacoemulsification or otherwise known as small incision cataract surgery. Most of the cataract surgeries performed today are done using this method. The surgeon will make a small incision on the side of the cornea, about 1/8 inch long. A probe is inserted, which vibrates with ultrasound waves that softens and breaks up the cataract then suctions it out.
The second method is called extra capsular cataract extraction. This method is used when the cataract has advanced beyond the point that the phacoemulsification would work properly. During this procedure, the surgeon will make a larger incision, about 3/8 inches long where the cornea and sclera meet. The surgeon will remove the cloudy core of the lens in one piece, and vacuums out the rest of the lens.
After these procedures are complete, an artificial lens is implanted. This implant is called an intraocular lens or IOL. This is made from plastic, acrylic, or silicone and becomes a permanent part of the eye. If there are other problems with the eye, this implant cannot be used, and with those patients, contacts or magnifying glasses are recommended.
After having cataract surgery, light can pass again through the cornea and the IOL to the retina. Some patients can see better after the surgery than have been able to in a long time. Some patients will still need to wear eyeglasses to focus the light.
Regular eye examinations are the best way for early detection. After age 60, you should get eye exams every year. There are a few steps that can be taken to help prevent or slow down the development of cataracts. These include not smoking, a balanced diet, protecting your eyes from the sun, and taking care of yourself if you have diabetes or any other medical conditions.
MayoClinic.com, May 2004, http://www.mayoclinic.com/print/cataracts/DS00050/DSECTION=all&METHOD=print
Medem, Inc., Medical Library, American College of Surgeons, http://www.medem.com/medlb/article_detaillb_for_printer.cfm?aritcle_ID=ZZZSOONFSWC&sub_cat=119
Cataract Surgery, Cataracts and the human eye,
National Eye Institute, June 2005, Cataract: what you should know
St. Lukes Cataract and Laser Institute, 1996-2004, eye conditions, cataracts