A cataract is a loss of transparency, or clouding, of the normally clear lens of the eye. As one ages, chemical changes occur in the lens that make it less transparent. The loss of transparency may be so mild vision is hardly affected or so severe that no shapes or movements are seen, only light and dark. When the lens gets cloudy enough to obstruct vision to any significant degree, it is called a cataract. Glasses or contact lenses cannot sharpen your vision if a cataract is present.

The most common cause of cataract is aging. Other causes include trauma, medications such as steroids, systemic diseases such as diabetes and prolonged exposure to ultraviolet light. Occasionally, babies are born with a cataract.

Reducing the amount of ultraviolet light exposure by wearing a wide-brim hat and sunglasses may reduce your risk for developing a cataract but once developed there is no cure except to have the cataract surgically removed. Outpatient surgical procedures can remove the cataract through either a small incision (phacoemulsification) or a large incision (extracapsular extraction). The time to have the surgical procedure is when your vision is bad enough that it interferes with your lifestyle.

Cataract surgery is a very successful operation. One and a half million people have this procedure every year and 95% have a successful result. As with any surgical procedure, complications can occur during or after surgery and some are severe enough to limit vision. But in most cases, vision, as well as quality of life, improves.

Your eye works a lot like a camera. Light rays focus through your lens on the retina, a layer of light sensitive cells at the back of the eye. Similar to film, the retina allows the image to be "seen" by the brain. But over time the lens can become cloudy and prevent light rays from passing clearly through the lens. This cloudy lens is called a cataract.

The typical symptom of cataract formation is a slow, progressive, and painless decrease in vision. Other changes include: blurring of vision; glare, particularly at night; frequent eyeglass prescription change; a decrease in color intensity; a yellowing of images; and in rare cases, double vision.

Ironically as the lens gets harder, farsighted or hyperopic people experience improved distance vision and are less dependent on glasses. However, nearsighted or myopic people become more nearsighted or myopic, causing distance vision to be worse. Some types of cataracts affect distance vision more than reading vision. Others affect reading vision more than distance vision.

A cataract is a clouding of the eye's normally clear lens. The lens of the eye plays an important role in focusing images on the retina, the light-sensitive nerve cells lining the back of the eye. If the lens loses its clarity, light rays do not focus clearly and vision is blurry. Just as it is hard to see through a dirty window, it is hard to see through a cataract. Although most cataracts occur in older adults, they can appear in children, in one or both eyes, often at birth. They look like a white or gray spot in the pupil.

Cataracts in children may be inherited or develop because of an infection or a disease acquired before birth, or as a result of an injury. In most cases, no specific cause is found.

Children may lose vision permanently because of amblyopia (lazy eye) if a severe cataract is not removed quickly. The better eye may also need to be patched. Mild cataracts may not need treatment.

The focusing power of the original lens, removed during cataract surgery, must be replaced to restore vision. Intraocular lenses (IOLs), permanent plastic lenses placed inside the eye, are implanted in older children much as they are in adults. In infants, IOLs are controversial because the eyes grow and change their prescriptions during the first few years of life. Many surgeons prefer contact lenses or even glasses for younger children.

Regardless of the type of correction, children need follow-up exams to avoid possible complications, including glaucoma, scar tissue forming in the pupil, and amblyopia. Often, children will need eye muscle surgery because the eye turns or crosses.

Despite these problems, cataracts are the single most treatable cause of childhood blindness. After surgery, most children can see the blackboard in school (20/60-20/100). While some do not do as well, with appropriate correction, many children see almost normally.

Extracapsular cataract extraction is a method for surgically removing a cataract, which is a clouding of the eye's naturally clear lens. A cloudy lens interferes with light passing through to the retina, the light-sensing layer of cells at the back of the eye.

Having a cataract can be compared to looking at the world through a foggy window. In extracapsular extraction, an incision is made in the side of the cornea at the point where the cornea and sclera, the white part of the eye, meet. Carefully entering the eye through the incision, the surgeon gently opens the front of the lens capsule and removes the hard center, or nucleus, of the lens. The soft lens cortex is then suctioned out leaving the back of the capsule in place.

An incision requiring sutures is necessary because the lens is removed in one piece. A plastic implant called an intraocular lens, or IOL, is substituted for the original lens. The implanted IOL allows light to be focused on the retina.

It may be up to six weeks before the sutures are removed and best-corrected vision is achieved. During recovery, it may be necessary to avoid bending over or lifting heavy objects.

An intraocular lens (IOL) is a tiny, lightweight, clear plastic disk placed in the eye during cataract surgery. An IOL replaces the focusing power of the eye's natural lens.

The lens of the eye plays an important role in focusing images on the retina. If the lens loses its clarity, as it does when a cataract develops, light rays do not focus clearly and the image one sees is blurry. Glasses or contact lenses cannot sharpen vision if a cataract is present.

The only treatment for a cataract is to remove the lens and implant an IOL. Intraocular lenses have many advantages. Unlike contact lenses, which must be removed, cleaned, and reinserted, the IOL remains in the eye after surgery.

An IOL may be placed either in front of or behind the iris. Behind the iris is the most frequent placement site. They can be hard plastic, soft plastic or soft silicone. Soft, foldable lenses can be inserted through a small incision which shortens recovery time following surgery.

Rapid evolution of IOL designs, materials, and implant techniques have made them a safe and practical way to restore normal vision after cataract surgery.

Phacoemulsification is a surgical method used to remove a cataract, which is a clouding of the eye's naturally clear lens. A cloudy lens interferes with light passing through to the retina, the light-sensing layer of cells at the back of the eye. Having a cataract can be compared to looking at the world through a foggy window.

In phacoemulsification, an ultrasonic oscillating probe is inserted into the eye. The probe breaks up the center of the lens. The fragments are suctioned from the eye at the same time. A small incision that often does not require sutures to close can be used since the cataract is removed in tiny pieces. Most of the lens capsule is left behind and a foldable intraocular lens implant, or IOL, is placed permanently inside to help focus light onto the retina. Vision returns quickly and one can resume normal activities within a short period of time.

Posterior Capsulotomy

A posterior capsulotomy is a surgical laser procedure that may be necessary after cataract surgery.

During cataract surgery part of the front (anterior) capsule that holds the lens is removed. The clear back (posterior) capsule remains intact. As long as that capsule stays clear one has good vision. But in 10 to 30% of people, the posterior capsule loses its clarity. When this happens, an opening can be made in the capsule with a laser (posterior capsulotomy) to restore normal vision.

Before the laser procedure, the ophthalmologist does a thorough ophthalmic examination to make sure there is no other reason for vision loss.

A posterior capsulotomy is painless and takes five minutes. Eye pressure is taken a half hour after the operation to make sure it is not elevated and antibiotic drops are usually prescribed for three days following the procedure. Vision should improve within hours.

Potential but rare complications following laser posterior capsulotomy are increased intraocular pressure and retinal detachment.