What Are Cataracts?
Although there are several different types of cataracts, they are all caused by a loss of transparency in the crystalline lenses of the eye. This loss causes a disruption in the transmission of light to the retina.
Who is affected?
Cataracts most commonly occur among people who are over 55, although it can affect younger people and, although very rare, has even been known to affect newborns. Twenty-three percent of those over 75 are affected by cataracts.
On a Global basis, cataracts account for over one-half of all cases of impaired vision and affect over 20 million people.
What causes the development of Cataracts?
Chemical changes within the protein material of the lens are responsible for clouding and yellowish or brownish discoloration. These chemical changes seem to be part of the natural aging process, although they may also be caused by injury, inherited tendencies, certain diseases, or birth defects.
Other contributing factors include exposure of the eye to ultraviolet light (sunlight), poor nutrition, cigarette smoking and certain drugs.
How do Cataracts Affect Sight?
The lens is normally clear so light can readily pass through it, producing a sharp image on the retina; when the lens becomes opaque, light can't pass through as easily. Having a cataract is like trying to look through a foggy window.
The cloudy lens blocks the passage of light, thereby casting a blurred image on the retina. Clouding of the lens may affect only a small portion of the lens, or may affect the entire lens.
Cataract formation may cause little or no visual problem for some people, especially in the early stage of the problem, but other experience a substantial decrease in vision that may requires surgery. Severe Cataracts may cause a complete loss in functional vision.
The degree to which a person's vision is affected by cataract formation depends on the location and degree of clouding. For instance, if the area clouding initially starts at the side of the lens, a person's vision may not be drastically affected for years, because peripheral vision is not used as mush as the central area. Cataracts typically develop in both eyes, although the rate of progression varies with each eye. The Onset of a cataract may be gradual or rapid. Cataracts Usually develop around age 50, but may not significantly interfere with sight until much later -age 65 to 75.
Clearing Up Cataract Myths.
Can Cataracts be Prevented?
There is no known prevention for cataracts that occur as a natural process of aging. However, there is growing evidence that exposure to Ultraviolet light (sunlight) and cigarette smoking may speed their development. Avoidance of excessive sun exposure and smoking is a sound preventative measure.
How are Cataracts Diagnosed?
A comprehensive eye health examination is needed to detect cataract formation. After diagnosis, regular follow-up care is needed to assure the best possible correction for the level of impairment.
What is the Treatment for Cataracts?
Prescription glasses can help you to see better. At some time, however, cataract may become so dense that the good vision can no longer be maintained with just prescription eyewear. At that time, surgery may be the best option to restore vision.
The decision regarding surgery is one that is made jointly by the patient and their eyecare professional. The decision of when to have a cataract removed depends on a number of factor, such as the extent of clouding, the location of the cataract, and the extent to which normal daily activities are impaired. For instance, if reading or driving abilities are impaired, surgery may be a more realistic consideration than if such impairments have not yet been noticed.
What Does Cataract Surgery Involve?
Cataract surgery has improved dramatically in the last decade with a very high success rate - 95 percent or better. Over one million cataract surgeries are performed annually. The surgery has few complications and an increasingly short recovery time. Most of the time, the procedure is done on an outpatient basis.
Because only one eye is operated on at a time, the more impaired eye is usually done first. Surgery is often timed such that the other eye still has adequate vision for one to function while the surgical eye has healed.
Cataract surgery involves the removal of the clouded lens. When the affected lens is removed (a condition in it's self known as Aphakia), the focusing power of the lens must be replaced. Often an artificial lens implant (known as an IntraOcular Lens implant or IOL) will be inserted into the eye immediately after the impaired lens is removed.
Eyeglasses and contact lenses are other forms of lens "replacement." However, since these replacements are not within the eye itself, vision is not as natural.
Sometimes cataract removal does not result in complete improvement in vision because sight is dependent on many other factors, such as the "health" of the retina, which may be impaired also. But, in such cases, proper eyewear can usually further enhance vision to an acceptable range.
Each of these replacements (IOL and prescription lenses) is designed to allowthe eye to again focus clearly.
Although no substitute is as good as the real thing - nature's own lens - the availability of replacements certainly is an improvement over earlier days when the development of cataracts simply meant a gradual, progressive loss of vision - period.
For more information, take a look at these links:-
Cataracts - A Useful Factsheet from the (RNIB)
Childhood Cataracts - Another useful Factsheet, which is great for concerned parents