Cataracts

What are cataracts?

Although there are several different types of cataracts, they are all caused by a loss of transparency in the crystalline lens of the eye. This loss of transparency causes a disruption in the transmission of light to the retina resulting in ‘foggy’ vision.

Who is affected?

Cataracts most commonly occur among people who are over 55. Although it can affect younger people and, rarely, can affect newborns. 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 brown discoloration. These chemical changes seem to be part of the natural aging process, although injury, inherited tendencies, certain diseases, or birth defects may also cause them. Other contributing factors include exposure of the eye to ultraviolet light, poor nutrition, 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 a small portion of the lens or the entire lens. Cataract formation may cause little on no visual problem in some people, especially in the early stages of the problem, but others experience a substantial decrease in vision that may require surgery. The degree to which a person’s vision is affected by cataract formation depends on the location and degree of clouding. Cataracts typically develop in both eyes, although the rate of progression may vary 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 a later age.

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) may speed the development, so avoidance of excessive exposure is a sound preventative measure. The use of UV protective eyewear will limit the exposure to UV light.
How are cataracts diagnosed?

A comprehensive eye health examination is needed to detect cataracts. 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?

Cataracts may cause a rapid change in refractive error which may require more frequent changes in prescription eyeglasses to help you see better. Eventually, when the cataract worsens, surgery may be necessary. The decision regarding surgery is one that is made jointly by the patient and the eye care professional. The decision of when to have a cataract removed depends on a number of factors, such as the extent of the clouding and extent to which normal daily activities are impaired.

What does cataract surgery involve?

Cataract surgery has improved dramatically in the last decade with a very high success rate. The surgery has few complications and a short recovery time. Often the procedure can be 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 until the surgical eye has healed. Cataract surgery involves the removal of the clouded lens. When the affected lens is removed, focusing power of the lens must be replaced. Often, an artificial lens implants will be inserted into the eye immediately after the impaired lens is removed. Sometimes cataract removal does not result in complete improvement of vision because sight is dependent on many other factors, such as the health of the retina.