Crossed eyes in babies are a cause for alert within the first year.
The eyes, the brain and vision all develop quickly during the first year of life as children begin to experience the world. Abnormalities in the way the visual system develops can produce life-long problems with vision. It is crucial that any suspected problems, including crossed eyes, be addressed early.
Having straight eyes is important for the development of binocular vision and depth perception. Unfortunately, about 3 percent of children develop misalignment of the eyes. Timely treatment by a pediatric ophthalmologist may prevent serious vision problems later in life.
If a baby has crossed eyes for the first few months of postnatal life this is relatively normal. However, any inward crossing after age 3 months, and any outward drifting after age 4 months, is not normal. This misalignment typically does not go away and warrants referral to a pediatric ophthalmologist.
The most common referrals for eye crossing during the first year of life are for children who appear to have crossed eyes, when in fact the eyes are straight. A relatively wide nasal bridge can give the appearance of crossed eyes. In this case, after a complete eye examination when dilating drops are used, we reassure the parents that all is well. These are the only children who appear to grow out of their eye crossing because the eyes were never crossed in the first place.
Causes of misaligned eyes in children
Infantile esotropia is characterized by a large-angle inward turning of the eyes that is develops within the first 6 months of life. It can be associated with mild neurologic delay and is probably caused by the inability of the brain to interpret two images as a single image. It does not resolve on its own. Treatment for infantile esotropia consists of eye muscle surgery. Eye muscle surgery is done as an outpatient procedure and usually involves both eyes.
The most common cause of eye crossing seen in children under the age of 5 years is called accommodative esotropia. Accommodative esotropia is caused by excessive farsightedness, and the need to focus the eyes produces an inward crossing of the eyes. Treatment for accommodative esotropia involves correcting the farsightedness with glasses. These children typically do extremely well and can eventually transition to contact lenses as they get older.
A small percentage of children with accommodative esotropia develop eye crossing that cannot be corrected fully with glasses. These children also need eye muscle surgery. The purpose of the surgery is to get the eyes straight with glasses on, not to eliminate the need for glasses. Surgery is often performed as soon as the child has good vision in each eye and can cooperate well enough to measure the amount of misalignment. Optimal results when the surgery is performed within six months of the onset of constant misalignment.
About 40 percent of children with esotropia develop amblyopia. Amblyopia occurs because the brain suppresses vision from the crossed eye. Treatment forces the misaligned eye to see by either patching the straight eye or using a drop that blurs vision in the healthy eye. When treated before age 5, more than 80 percent of children diagnosed with amblyopia associated with esotropia eventually improve to the point of having legal driving vision in the amblyopic eye.
If you feel your child has a problem with vision or eye alignment, ask your pediatrician for a referral to a pediatric ophthalmologist. Typically, your child will have his or her eyes dilated. Unfortunately, there is no way to appropriately assess a child’s vision without using dilating drops.
Written by Sean Donahue, M.D., Ph.D., professor of ophthalmology, pediatrics and neurology at Vanderbilt whose specialties include amblyopia and visual development. Donahue is chief of pediatric ophthalmology at the Tennessee Lions Eye Center.