Pediatric Vision Disorders
More on Cataracts

Cataract (cloudiness of the crystalline lens).
An eye disease such as a cataract may lead to amblyopia. Any factor that prevents a clear image from being focused inside the eye can lead to the development of amblyopia in a child. This is often the most severe form of amblyopia.

Cataract is a clouding of the normally clear lens inside the eye and is known primarily as a common cause of poor vision in older adults, but it also occurs uncommonly in babies and children. When cataract is present in both eyes, family members can usually tell that there is a problem with vision. When only one eye is affected, the child most often seems to see normally. A cataract may make the black pupil of the eye look white or gray. Sometimes eyes with cataract wander out of line, or show jiggling movements (nystagmus). Often, though, the child�s eyes look perfectly normal to family members. Cataract in childhood may be caused by injury to the eye, or by a problem with the child�s general health. Sometimes it is passed on to the child by heredity, usually from a parent who has had the same problem.

The crystalline lens is located behind the colored iris and it functions to help focus light entering the eye. When cataract is present, vision is lowered because light cannot properly reach the retina. Glasses alone are not able to bring back sight lost because of cataract. In some cases, vision loss is so mild no treatment is necessary. Usually, though, the cloudy lens must be removed with surgery before the eye can see well. Cataract surgery is a major eye operation that must be done with the child asleep under general anesthesia. It can be performed at any age (even in babies just a few days old). Most of the lens is removed using very delicate surgical instruments (not a laser) through a small opening into the eye. Usually the child feels little or no pain, and goes home a few hours after surgery. The eye needs to be examined in the ophthalmologist�s office the next day, and several more times during the next few weeks. The child has to wear a protective shield over the eye for a while, and activity is restricted for up to one month.

To see their best after cataract surgery, children often need to wear glasses, and sometimes contact lenses. Without these, vision may stay low. Many children, especially if they have had a cataract in only one eye before age 5 years, need treatment for amblyopia after surgery. Usually this involves placing a patch over the good eye for at least a few hours a day, forcing the child to use the other eye. Children often object strongly to wearing a patch, but unless this treatment is effectively done, vision may never recover from the harm caused by the cataract. The first few months after surgery are the most important time for treating amblyopia, but usually some amount of patching must be continued up to about age 10 years. Most children who are treated for cataract end up seeing well. Occasionally, though, even with the best possible treatment vision stays low.

When the crystalline lens is removed about 15.00 diopters of plus power is also removed from the optical system of the eye and must be replaced. There are at present three commonly used ways to fill this refractive need. The first is with eyeglasses. The main advantages of glasses after cataract surgery are that they carry no risk of harming the eye, and they are very convenient and simple to use, and they often produce sharp vision. The main disadvantage is that they are generally quite thick, and older children (teenagers) may object to their appearance and may find it difficult to play sports in them. Also, glasses are generally not good for use after cataract surgery on one eye only; the images from the two eyes cannot be properly fused due to the difference in magnification between a plano or low powered and an aphakic lens containing 10 or more diopters of plus power.

The second way to fill the refractive need of a child who has had cataract surgery is to use contact lenses, which are worn directly on the cornea. Contact lenses usually provide both vision and appearance that is very natural. They can be used after cataract surgery on one or both eyes. Children of all ages usually are quite comfortable wearing contact lenses. Lenses are available that can be worn continuously for about a week at a time. It is important, though, to remove them regularly for cleaning. The main disadvantages of contact lenses after cataract surgery are that in young children (especially between about 1 and 5 years of age), placing them in the eye and removing them for cleaning can be difficult, and they can be lost when the child rubs the eye and so in some cases need to be replaced fairly often. With babies and school age children, family members usually learn to handle contact lenses well in a short time. Contact lenses are very safe when properly cared for. Rarely, though, they can cause serious eye infections, especially if care instructions are not followed. Some children wear contact lenses part of the time and glasses part of the time, depending on their particular needs or wants at the moment.

The third way to provide refractive correction after cataract removal is by implantation of an intraocular lens, or IOL. An IOL is a tiny object that is placed inside the eye surgically, usually during the same operation in which the cataract is removed. IOLs, like contact lenses, usually provide vision and appearance that is very natural. Their main advantages over contact lenses are that once in place usually the only attention they need is regular check-ups by the ophthalmologist, and they are present constantly to do their job, so the child never has to put up with blurred vision even for a short time. The primary disadvantage of IOL implantation is that once the lens is inside the eye, it is very difficult to remove or replace. This is important, especially for younger children, because as the eye grows and matures, the refractive error can change quite a bit. For this reason, the child who has had IOL surgery may still need to wear glasses or contact lenses at certain ages, although they do not have to be as strong as what would be needed without the implanted lens. IOLs have been used in a very large number of adults who have had cataract surgery within the past 15-20 years, and have been found to work very well and to be very safe.IOL implantation in children has become popular only within the past few years, and there is still a good deal to be learned about how well it will work and how safe it will be over a long lifetime. No serious or unexpected problems have been found so far. The risk of a surgical complication that might harm the child�s eye is slightly higher when an IOL is implanted.

A child who has cataract surgery now without an IOL may be able to have one placed in the future with a second operation, but there are some extra risks and disadvantages to secondary lens implantation. A natural lens can accommodate to adjust the eye�s focus from distance to near which of course an IOL cannot do. Therefore is often necessary to provide the child who has had cataract surgery with additional refractive correction for seeing up close. This is usually done by means of bifocal or reading glasses, which may be needed (with low power lenses) even if contact lens wear or IOL implantation has been chosen. Sometimes, for a particular child there is only one method of refractive correction after cataract surgery that seems likely to work well. In many cases, though, there is more than one good way to fill the refractive need. The specific condition of the child�s eyes and general health, and the specific concerns and wishes of the family are very important in making the decision about whether glasses, contact lenses, or IOL implantation should be used.