Down syndrome is a genetic condition resulting from an extra copy of chromosome 21. This additional genetic material influences development, leading to recognizable physical characteristics, with some of the most distinct affecting the eyes. The structure and function of the eyes in individuals with Down syndrome present unique considerations, making early and consistent ophthalmic care a priority. The condition is associated with a higher likelihood of developing vision problems, from common refractive errors to more complex issues that can impact sight.
Distinctive Anatomical Eye Features
The eyes of individuals with Down syndrome often have a distinct appearance due to several anatomical features. One of the most recognized is upslanting palpebral fissures, where the outer corner of the eye is positioned higher than the inner corner. This gives the eyes an almond-like shape but does not affect vision.
Another common trait is the epicanthal fold, a small flap of skin on the inner corner of the eye. These folds can be present in infants of all ethnicities but typically disappear as the bridge of the nose develops. In individuals with Down syndrome, these folds are often more pronounced and may persist into adulthood.
Many people with Down syndrome also have Brushfield spots, which are small, white, or light gray specks on the iris. These spots are harmless accumulations of a normal iris protein called collagen and do not affect vision. They can sometimes be seen in people without the condition, although they are far more prevalent in those with Trisomy 21.
Associated Ocular and Vision Problems
Individuals with Down syndrome have a significantly higher incidence of ocular health conditions that can affect their vision. Refractive errors—issues with how the eye focuses light—are exceptionally common. These include hyperopia (farsightedness), myopia (nearsightedness), and astigmatism, meaning a large percentage of children with the condition will require glasses to see clearly.
Strabismus, or a misalignment of the eyes, is another frequent diagnosis, affecting between 20% and 60% of this population. This condition, where the eyes may turn inward (esotropia) or outward (exotropia), can lead to amblyopia, commonly known as “lazy eye,” if not treated. Nystagmus, characterized by involuntary and rapid eye movements, is also more prevalent.
Certain structural eye problems occur more often as well. Cataracts, which cause a clouding of the eye’s lens, can be present at birth (congenital) or develop later. Congenital cataracts are a particular concern because if not removed early, they can prevent the brain from learning to see, resulting in permanent vision impairment. Many individuals also experience blocked tear ducts, leading to watery eyes and a higher risk of infection. During adolescence, some may develop keratoconus, where the cornea thins and bulges into a cone shape, causing distorted vision.
Medical Oversight and Interventions
Given the high frequency of eye-related issues, proactive medical care is a standard part of managing health for individuals with Down syndrome. Health guidelines recommend a first eye exam within the first six months of life, followed by regular check-ups. These early screenings by a pediatric ophthalmologist are designed to detect conditions like congenital cataracts and strabismus when interventions are most effective.
For refractive errors, corrective lenses are the primary treatment. Glasses or contact lenses can effectively manage nearsightedness, farsightedness, and astigmatism. In cases where strabismus leads to amblyopia, patching therapy is a common approach. This involves covering the stronger eye for periods to force the brain to use and strengthen the weaker eye.
Surgical procedures are available for several of the more serious conditions. Cataract surgery involves removing the clouded lens and, in most cases, replacing it with an artificial one. Surgery may also be recommended to correct severe cases of strabismus by adjusting the muscles that control eye movement. For blocked tear ducts that do not resolve on their own, a minor surgical procedure can open the drainage system. Keratoconus requires ongoing monitoring and may eventually necessitate specialized treatments.