Paediatric Cataracts

Cataracts in children are relatively uncommon but, if not treated promptly, can result in permanent, severe visual loss. Most cataracts in children are not associated with any other eye-related or systemic abnormality. In some cases, however, cataracts may be part of a systemic disorder involving muscles, brain, kidneys or other organs. Cataracts in children are often, but not always, hereditary.

A cataract is an opacity of the lens of the eye. Cataracts may involve one or both eyes. In some cases severe cataracts are present at birth and require prompt removal in order to insure normal visual development of the affected eye(s). In some older children, cataracts may be very mild or even absent at birth, but may progress during childhood and require removal to obtain good vision. In most cases, the cataract is the only abnormality in the eye. However, cataracts may be part of a more extensive pattern of ocular malformation, including abnormalities of the lens and retina. Cataracts also may be associated with elevated intraocular pressure, i.e. glaucoma.Cataracts also can occur as a result of trauma. Traumatic cataracts usually result from penetration of the eye by a foreign body, e. g. a projectile such as a BB, or a jab to the eye with a pointed object. Cataracts also may also occur after infection or inflammation of the interior of the eye. Not all cataracts in children require removal. Some are quite mild and are compatible with excellent vision. However, most cataracts in children will require removal to establish, or to reestablish, good vision. There are some technical differences in surgical technique between cataract extraction in adults and children, but, for most part, the procedure in children is quite similar to that in adults. After the lens material is removed, both children and adults will require a substitute lens to focus the eye. There are three options: insertion of an intraocular lens, a contact lens or glasses. For children older than 2, insertion of an intraocular lens is the preferred method of optical correction. For children younger than 2, insertion of an intraocular lens is somewhat controversial. Because the eyes of infants and toddlers are still growing, an intraocular lens placed at age 6 or 12 months may not have the appropriate optical power for the eye as the child grows. This will result in a blurred image, and the intraocular lens and will need to be replaced. Contact lenses are a good option for these infants and toddlers, and an intraocular lens may be placed, if desired, at a later date. Spectacles are an old, tried and true option for children with congenital cataracts, but only may be used in children who have had bilateral cataract surgery. Spectacles magnify the retina image by about 15 to 20 percent after cataract surgery. This is not a problem in children or adults who have had bilateral cataract surgery, as the two images (one in each eye) will be of equal size. However, unilateral magnification is not well tolerated, and for that reason, spectacles cannot be used for children who have had unilateral cataract surgery. Removal of the cataract is only the first step in the rehabilitation of children with congenital cataracts. In many cases, the child will develop a strong preference for one eye and will not develop the brain circuits required for good vision in the non-preferred eye if patching is not undertaken. Children with unilateral cataracts virtually always require a great deal of patching of their normal eye after cataract surgery to help their brains develop new circuits for the formerly cataractous eye. This is because the brain has been deprived of stimulation from the cataractous eye, and in children, the brain does not develop the circuitry needed to see well. Patching the better eye forces the brain to build the new circuits that process information from the formerly cataractous eye. Many children with cataracts will also develop strabismus, or crossed eyes, at some point either before or after removal of their cataract(s). These children will need eye muscle surgery to help them develop binocular vision. Finally, about 30 percent of children who have had surgery for congenital cataracts, and a somewhat smaller number of children who have had surgery for juvenile cataracts, will develop glaucoma, i.e. increased pressure in the eye. Glaucoma can develop at any point after cataract surgery, from a month to many years later. In order to prevent visual loss from glaucoma, children who have had cataract surgery require frequent exams to check their intraocular pressure. Because infants, toddlers and many small children will not permit an intraocular pressure check, which requires an instrument to touch the anesthetized eye, periodic eye examinations under general anesthesia are needed. If glaucoma develops, it must be treated vigorously with medication and, in some cases, surgery. As in adults, retinal detachment may occur as a complication of cataract surgery. This complication is relatively uncommon, but children who have undergone cataract surgery require lifelong monitoring with periodic eye examinations to rule out retinal detachment.Despite these potential pitfalls, cataract surgery in children is generally successful, though parents must be prepared for a prolonged rehabilitation process.Joel Weinstein is a staff physician and associate professor of ophthalmology and paediatrics, and David Liang is a staff physician and assistant professor of ophthalmology at Penn State Milton S. Hershey Medical Center and Penn State College of Medicine. (Source: Joel Weinstein, David Liang : Pennsylvania State University : October 2007)