Children with Cataracts


The lens of the eye is located directly behind the iris (colored part of the eye), and the pupil, which is the dark hole in the center of the iris. The lens is the focusing device of the eye and works like a camera lens does to focus clear images onto the retina. The lens can change its locus because it is surrounded by a flexible envelope or capsule that has many fine fibers attached to it. These fibers hold the lens in its position within the eye, and change the shape of the lens to focus at different distances

Normally, the lenses in your eyes are crystal clear. Cloudiness of the lens is called a cataract. Cataract development can be compared to what happens to the clear egg white when it is cooked and turns white. This process can not be undone and in order for a person to see clearly again the cloudy lens must be removed and focusing power restored.

Cataracts develop most often in older people but children can also be affected. Sometimes a child is born with a cataract, or the lens may become cloudy at a later age. One of the common causes of acquired cataracts in children is trauma to the eye. In others cataracts may be inherited, or have developed because of diseases which involve other parts of the body as well as the eye. In most cases of infant cataracts, no cause can be found.

Some cataracts in children may only partially cloud the lens and not interfere with vision. These small lens opacities usually do not require treatment except for periodic observation. Larger opacities which interfere with vision may require treatment with glasses or patching. Surgical removal of the lens may not be required in these children. Some cataracts interfere significantly with vision and require surgery. The type of cataract operation is individualized for each patient. Once the cataract is removed optical correction is essential.

An incision is made in the area where the cornea (the clear area over the front of the eye) and the white part of the eye meet Both the cloudy lens and its surrounding envelope or capsule may be removed. In some cases only a very small opening is made into the eye through which a needle is inserted to aspirate or suction out the cataract. All cataract operations involve making incisions into the eye. Lasers can not remove cataracts. During the operation, the surgeon looks through a microscope using high magnification to aid in this delicate surgery.

OPTICAL CORRECTION

After the cataract surgery the operated eye(s) must be provided with an artificial lens to perform the focusing functions of the removed lens. There are four ways of restoring focusing power to the eye when the natural lens has been removed. These are: eyeglasses, contact lenses, an epikeratophakia corneal graft (a specially ground piece of clear covering of the front of the eye) surgically stitched onto the surface of the eye, and intra ocular lenses. Glasses worn in front of the eye or contact lenses worn upon the eye are the most commonly used means of correcting vision after cataract surgery in children. Regardless of which type of visual correction is used, the child will still need bifocals to see close objects clearly. (show photos of glasses and contacts, epikeratophakia, and IOL)

A child with a cataract in only one eye presents a difficult problem. Correcting vision in the operated eye only with eyeglasses makes the images seen by that eye different from the normal eye. This is a form of double vision, and the child's brain will suppress or "turn off" the image from the operated eye. For these children, a contact lens is necessary.

Several varieties of contact lenses are available: rigid, soft daily-wear, and extended-wear lenses. The latter lens may remain upon the eye for days without removal. The type of contact lens selected depends upon the shape of the child's eye, the ease of lens insertion and removal by the child or the parents, the power of the lens, and the ability of the child's eye to adapt to a contact lens. Several types of contact lenses may be tried before the proper one is selected. Since an infant's eye grows rapidly, lenses fit during the first months of life need to be changed as the child grows. If contact lens wear is not successful, an epikeratophakia graft may be considered.

Another method of correcting vision after the cataract surgery in special cases is to insert an intra ocular lens. This plastic lens is placed inside the eye, where the original lens was, either at the time of the original cataract surgery or during surgery at a later time. The optical correction is constant, and the images seen by both eyes are of equal size. These lenses may be implanted in patients who have had cataract surgery in one or both eyes, and who have otherwise healthy normal-sized eyes.

Intra ocular lenses are not usually inserted in young infants as the rapid growth of the eye changes the focusing power of the eye greatly during the first year of life and the power of the implanted lens does not change appropriately. Children can develop severe complications such as inflammation and scarring with lens implants and the long term safety of the implants in children has not been established.

AMBLYOPIA

"Amblyopia " is a term meaning poor vision, and one of the causes of amblyopia is a cataract. Research using cats and monkeys has shown that when an animal has a cataract from a very early age, the lack of vision in that eye or "visual deprivation" leads to changes in the animal's brain as the animal grows and develops. As soon as the brain stops receiving a clear, formed image from an eye, the visual part of the brain for that eye stops developing. For this reason, when a baby is born with a visually significant cataract, ophthalmologists usually recommend that the cataract(s) be removed in the first few weeks of life, so that vision may be restored as quickly as possible.

If a cataract develops in early childhood, surgery should be performed as soon as vision is lost. However, when older children lose vision due to a cataract, they usually can be treated in the same way as adults because they have completed their visual development and there is little danger of amblyopia.

The treatment for amblyopia is to provide a clear visual image to be transmitted the brain. To do this, proper optical correction is worn and the good eye is patched until vision is developed in the operated eye. Covering up the good eye forces the weaker eye to learn to function . Even after the weak eye has become strong, patching may be continued on a part-time basis until the child is visually mature (about age 9). If patching treatment is not carried out after cataract surgery, good vision usually can not be developed. Even with the prompt therapy some children develop only partial visual recovery in the eye from which the cataract has been removed. This may be due to the presence of other eye defects.

Often children with cataracts will develop misalignment of their eyes (strabismus). This misalignment usually can be treated with eye muscle surgery to straighten the eyes.

Remember, a pediatric ophthalmologist is the only doctor who Provides total eye care for children: medical surgical and optical.