A cloudy or opaque area in the lens of the eye (see also congenital cataracts ).

Alternative Names

Lens opacity

Causes, incidence, and risk factors

The lens of an eye is normally clear. If the lens becomes cloudy or is opacified it is called a cataract. Cataracts may rarely be present at or shortly after birth in which case they are called congenital cataracts. Adult cataracts usually develop with advancing age and may run in families. Cataracts are accelerated by environmental factors, such as smoking or other toxic substances. Cataracts may develop at any time throughout life following an eye injury. Cataracts may also develop in response to metabolic diseases such as diabetes . Certain medications, such as cortisone, may accelerate cataract formation. Congenital cataracts are cataracts which are present from birth (or appear shortly after). They may be familial (autosomal dominant inheritance), or they may be caused by congenital infections such as rubella , or associated with metabolic disorders such as galactosemia . Risk factors include inherited metabolic diseases, a family history of cataract, and maternal viral infection. Adult cataract is generally associated with aging. It develops slowly and painlessly with a gradual onset of difficulty with vision . Visual problems may include difficulty seeing at night, halos around lights or glare sensitivity, and finally, decreased visual acuity , even in daylight. Adult cataracts are classified as immature, mature, and hypermature. A lens that has some remaining clear areas is referred to as an immature cataract. A mature cataract is completely opaque. A hypermature cataract has a liquefied surface that leaks through the capsule and may cause inflammation of other structures in the eye. Most people develop some clouding of the lens after the age of 60. The incidence of visually significant cataract ranges from 50 percent of Americans ages 65 to 74 to about 70 percent of those age 75. Most people with cataract have similar changes in both eyes, although one eye may be worse than the other. Many people with cataract have only minimal visual changes and are not aware of their cataracts. Factors that may contribute to cataract development are low serum calcium levels, diabetes, long-term use of corticosteroids, and various inflammatory and metabolic disorders. Environmental causes include trauma, radiation exposure, and excessive exposure to ultraviolet light (sunlight). In many cases, the cause of cataract is unknown.

Signs and tests

Treatment

OVERVIEW: The only treatment for cataract is surgical removal. This is done when a person cannot see well enough with glasses to perform their normal activities. For some people changing their glasses, getting stronger bifocals, or using a magnifying lens is helpful enough. Others choose to have cataract surgery . If a cataract is not bothersome, then surgery is usually not necessary. On occasion, there may be an additional eye problem that cannot be treated without first proceeding with cataract surgery. SURGERY: Cataract surgery consists of removing the lens of the eye and replacing it with an artificial plastic lens. A cataract surgeon will discuss the options with the patient and together they will decide which type of removal and lens replacement is best. LENS REMOVAL: There are 2 different types of surgery that can be used to remove lenses that have a cataract. Extracapsular surgery consists of surgically removing the lens, but leaving the back half of the capsule (the outer covering of the lens) intact. High frequency sound waves (phacoemulsification) may be used to soften the lens to facilitate removal through a smaller incision. Intracapsular surgery involves surgically removing the entire lens, including the capsule. This is done very rarely today. LENS REPLACEMENT: People who have cataract surgery usually get an artificial lens at the same time. The artificial lens is a plastic disc called an intraocular lens. It is usually placed in the lens capsule inside the eye. Other options include contact lenses and cataract glasses. Surgery can be done in an outpatient center or hospital. Most people do not need to stay overnight in a hospital. A patient will need a friend or family member to assist with travel home and home care after outpatient surgery. Follow up care by the surgeon is important.

Expectations (prognosis)

For most people, cataract surgery has a low risk of complications. With implanted artificial lenses, most people no longer need corrective lenses for distance vision. Glasses are usually necessary for reading.

Complications

Vision may not improve to 20/20 after cataract surgery if other eye diseases such as macular degeneration are present. Ophthalmologists can usually, but not always, determine this in advance. In infants, amblyopia and decreased visual development may occur as a result of cataract. Early diagnosis and treatment is essential.

Calling your health care provider

Call for an appointment with your health care provider if you have symptoms of cataract such as progressive deterioration of vision, decreased night vision, or problems with glare. Also call if you have a family history of congenital cataracts or if your child has symptoms or signs suggestive of a cataract.

Prevention

The primary prevention involves controlling associated diseases and avoiding exposure to factors known to promote cataract formation. Wearing sunglasses when you are outside during the day can reduce the amount of UV light your eyes are exposed to. Some sunglasses do not filter out the harmful UV. An optician should be able to tell you which sunglasses filter out the most UV. For patients who smoke cigarettes, quitting will decrease the risk of cataracts.