A cataract is any clouding of the eye’s natural lens. The natural lens is normally clear, and lies behind the iris and the pupil. When we think of cataracts, we typically think of older adults, but it is a condition that can affect both infants and older children.
Approximately 3 out of 10,000 kids have a cataract in the U.S. Some cataracts are present at birth (congenital cataracts) while other develop later (acquired cataracts). They can affect one eye (unilateral) or both eyes (bilateral). The cataract may also affect different parts of the lens and can range in size from a tiny dot to a dense cloud.
Causes of Pediatric Cataracts
Majority of pediatric cataracts have no identifiable cause, this is especially true if the cataract affects only one eye.
For bilateral cataracts (both eyes), the most common identifiable cause is a genetic mutation. Numerous genes involved in cataract formation have been identified. There are ongoing clinical studies to look at the genetic basis of congenital cataracts.
Other causes include: metabolic disorders (such as diabetes, Wilson disease), part of a syndrome (such as Down Syndrome), infections during pregnancy, inflammation, or trauma.
Symptoms of Pediatric Cataracts
Infants with mild cataracts and/or unilateral cataract may have no discernible symptoms of poor vision. This can lead to a delay in the diagnosis.
Some children may show a lack of reaction to light, failure to notice toys or faces, strabismus (misalignment of the eyes), or sometimes nystagmus (involuntary shaking of the eyes).
A cataract is often suspected when there is a missing or irregular red reflex. This is often detected when the child is first examined at birth, at a later well-baby exam, or noticed by parents.
How does a cataract affect vision?
Light enters the eye and is projected onto the retina (inner surface of the back of the eye) which transmits the signal to the brain. Since all light that enters the eye must pass through the lens, any clouding of the lens will affect the amount and clarity of light that can enter. In cases of very dense or large cataracts, it may stop light from reaching the retina altogether, therefore preventing the eye from seeing.
For children, whose eyes and brain are still learning to see, clear light is a must for the brain to receive a clear image. Any distortion or loss of light will limit a child’s visual development and cause amblyopia. Therefore, the younger the child, the more important it is for timely evaluation and treatment of their cataract.