Down syndrome has effects on the developing eye which can impact the proper development of vision. Eye disease is reported in over half of patients with Down syndrome, from less severe problems such as tear duct abnormalities to vision threatening diagnoses such as early age cataracts. Particular attention should be paid to vision in people with Down syndrome.
What is Different About the Eyes in Individuals With Down Syndrome?
The eyes of individuals with Down syndrome usually have some distinguishing characteristics. These include upward slanting of the eyelids, prominent folds of skin between the eye and the nose, and small white spots present on the iris (the colored part of the eye) called Brushfield’s spots. These spots are harmless, and can be seen in people without Down syndrome as well.
Do Most Children With Down Syndrome Need Glasses?
Refractive error (the need for glasses) is much more common in children with Down syndrome than in the general population. This refractive error can be hyperopia (farsightedness), astigmatism, or myopia (nearsightedness). Another problem is weak accommodation (difficulty changing the focusing power of the eye from distance to near). If detected, glasses that have bifocals should be prescribed.
What Are Common, but Less Serious, Eye Abnormalities Affecting Patients With Down Syndrome?
In addition to the need for eyeglasses, many children with Down syndrome have tear duct abnormalities. Family members will notice this as frequent discharge and tearing from the eyes, worsened by colds. Firm massage over the space between the eye and the nose (tear sac region) 2-3 times a day to attempt to open the tear duct is recommended. If this continues beyond a year of age, the tear ducts may need to be opened surgically.
Strabismus (eye misalignment) is also more common. Family members may notice that the eyes do not line up well with each other, but often the strabismus can be subtle, even to the pediatrician. The folds of skin between the eyes and the nose can also cover up the underlying strabismus, or make the eyes appear as if they are crossing even if they are not. It is important to diagnose strabismus during childhood, as crossed eyes can result in amblyopia (loss of vision also known as lazy eye) and loss of stereopsis (the use of the two eyes together, or depth perception).
How can Strabismus be Treated?
Sometimes, simply glasses alone are enough to straighten eyes with strabismus. If the eyes continue to have strabismus despite the correct pair of eyeglasses, then strabismus surgery (eye muscle surgery) is necessary. This is a one to two hour procedure, which can often be done as an outpatient unless there are other reasons the person would need to be admitted, such as a serious heart condition. Unfortunately, patients with Down syndrome are more likely to require more than one surgery to align their eyes as they don’t always respond as predictably to strabismus surgery as the general population with strabismus does.
What are the More Severe Eye Problems That Might Develop?
The greatest concern is congenital cataracts (lack of clearness to the lens of the eye). If visually significant cataracts are present early in a child’s eye, then a clear image is not delivered to the brain and therefore the brain can never “learn” to see. This is a severe form of amblyopia known as deprivational amblyopia. Significant cataracts that are present very early in a child’s life must be removed or they can result in lifelong poor vision. In that situation, even if the cataract is removed when the child is older, the vision never improves significantly. This is what makes early detection of cataracts in infants and children so important. A child with Down syndrome will be evaluated by the pediatrician at birth, and referred to an ophthalmologist if something abnormal is detected. There is also a unique form of cataract in Down syndrome patients. However, depending on how developmentally delayed the person is, they may not be able to communicate that they can’t see. Therefore, any patient with Down syndrome, no matter what age, should have a complete eye examination if they are starting to show reduced cognitive function, or changes in their normal activities.
Are There Other Eye Conditions in Down Syndrome That can Cause Loss of Eyesight?
Amblyopia (commonly called “lazy eye”) can be caused by multiple different eye problems such as strabismus, severe ptosis (eyelid droop), cataracts, or even uncorrected refractive error, especially if one eye needs a much stronger eyeglass prescription than the other. Ptosis is usually easier to appreciate but strabismus and significant refractive error can be very difficult for the pediatrician to diagnose. There are other rarer problems which can occur with the optic nerve or retina of the eye which can sometimes cause vision loss and unfortunately are generally not treatable. Nystagmus (a rhythmic shaking of the eyes) can also occur.
What is the Recommended Eye Care for Children with Down Syndrome?
The American Academy of Pediatrics (AAP) and the Down Syndrome Medical Interest Group (DSMIG) recommend evaluation of the red reflex of the eyes at birth to look for cataracts, as well as to assess the eyes for strabismus or nystagmus. The red reflex is essentially the “red eye” seen in photography, which is the normal reflex of the retina when struck by direct light. If the eyes don’t look normal, then the infant will be referred to a pediatric ophthalmologist. A child with Down syndrome should have his or her first eye exam by an ophthalmologist experienced in patients with special disabilities (for example, a pediatric ophthalmologist) by six months of age. After that, children with Down syndrome, even if they have no symptoms, should see an ophthalmologist every one to two years. If any eye problems are detected, they should be followed more frequently.
What Sort of Symptoms Does a Child With an Eye Problem Have?
Unfortunately, children with Down Syndrome often do not complain about their eye problems, either because they don’t notice the problem or because they can’t communicate the problem well enough. Signs to look for include squinting or closing one eye shut, an unusual head tilt, crossing or wandering of one or both eyes, or light sensitivity. In some severe cases, the sign of vision problems may be a regression in overall function or loss of developmental milestones. Ptosis will be seen as a lid droop, and a blocked tear duct will result in daily tearing and discharge.
The information featured in this section is reproduced via an exclusive arrangement with National Down Syndrome Society [ONLINE] Available at http://www.ndss.org