For this article, NDSS interviewed Danielle Ledoux, M.D., who specializes in Ophthalmology at Children's Hospital Boston.
Down syndrome has effects on the developing eye, which could influence 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. Caregivers and doctors should give particular attention to vision in people with Down syndrome.
What is different about the eyes in Down syndrome?
A person with Down syndrome has characteristic features about the eyes. This includes 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 people without Down syndrome have them 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 it is 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). We can test this easily in the office, and if it's detected, we will prescribe glasses that have bifocals. Some of my patients have difficulty adjusting to glasses, but once they get accustomed to having the glasses on their face, their vision is significantly better and often their eye alignment improves as well.
What are common, but less serious, eye abnormalities affecting patients with Down syndrome?
In addition to refractive errors that require 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. We generally recommend firm massage over the space between the eye and the nose (tear sac region) two to three times a day, to attempt to open the tear duct. If this continues beyond a year of age, a surgical procedure may be necessary to open the tear ducts. Strabismus (eye misalignment) is also more common in people with Down syndrome. 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 I mentioned 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 when the patient is a child, 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).
What is the treatment for strabismus?
Simply glasses alone are sometimes enough to straighten eyes with strabismus. If glasses are needed, we always start there. If the eyes continue to have strabismus despite the correct pair of eyeglasses, then we recommend strabismus surgery (eye-muscle surgery). This is a one- to two-hour procedure, often done as an outpatient procedure unless there are other reasons to admit the patient, such as a serious heart condition. Unfortunately, our patients with Down syndrome are more likely to require more than one surgery to align their eyes, because they don't always respond as predictably to strabismus surgery as the general population with strabismus does.
Understanding More Eye and Vision Problems
What are the more severe eye problems that might develop?
My greatest concern is congenital cataracts (lack of clearness in 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. While we can take our time removing a cataract in an adult patient, a significant cataract that is present very early in a child's life and that is not removed 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 that we have found in our research. However, depending on how developmentally delayed the person is, she may not be able to communicate that she can't see. For this reason, I recommend that any patient with Down syndrome, no matter what age, have a complete eye examination if they are starting to show reduced cognitive function or any changes in their normal activities.
Are there other eye conditions in Down syndrome that can cause loss of eyesight?
I mentioned amblyopia (commonly called "lazy eye," which is decreased vision), which 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 easy to discern, but strabismus and significant refractive error can be very difficult for the pediatrician to diagnose. There are other rarer problems that can occur with the optic nerve or retina of the eye that 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 United States 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 physician who has completed specialty training in medical and surgical management of the child's eye. We, along with the AAP and the DSMIG, recommend that a child with Down syndrome has her first eye exam by an ophthalmologist experienced in patients with special disabilities (for example, a pediatric ophthalmologist) by 6 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, the doctor can follow them more frequently.
What sort of symptoms might we see if a child has an eye problem?
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.
Any thoughts for parents of a child with Down syndrome who are concerned about the eye or vision?
Getting regular eye exams is very important for children with Down syndrome because eye disorders are so common and are difficult for the pediatrician to diagnose. The examination can be difficult for both the child and the doctor, so it's best to have the examination done by an ophthalmologist who is skilled in dealing with children with developmental delays. Don't be surprised to find out that your child needs glasses; if needed, the glasses will help her vision and possibly her eye alignment, as well as help in the development of normal vision pathways in the brain. This will help with your child's learning and overall functioning. Our research is looking at just how common eye problems are in Down syndrome, as well as the development of cataracts in these patients.
Originally featured on National Down Syndrome Society (NDSS.org) and reprinted with permission. Copyright ? 2012 Meredith Corporation.