Sometimes babies look like they have one eye turning in or out. When this asymmetric appearance appears consistently it can mean that the baby has a “lazy eye.” Muscle weakness or poor vision can result in an eye that doesn’t seem to be in sync with the other eye as it should when the baby is trying to track a moving object or when the child is looking intently at something. This out-of-sync appearance is called disconjugate gaze or strabismus, and if it remains uncorrected can result in permanent vision loss called amblyopia.
Not all babies, though, who appear to have disconjugate gaze or strabismus actually do have it. There’s a simple set of tests parents can do to determine if their baby or young child needs attention.
First, take a photo when you see the eyes misaligned. This will allow you to have more time to scrutinize the landmarks you need to observe to determine if the eye issue is real or just an optical illusion. With the photo in front of you, look at the light reflex on the iris/pupil area of both eyes. If the light reflex is symmetric (at about 2 o’clock on both eyes, for example) regardless of whether the eye appears to turn in or out, the appearance is due to the shape of the eyelid opening and not due to a weakness of vision or eye muscle.
If you are unsure, take a bunch of photos and see whether or not the symmetric appearance of the light reflex is there. If the light reflex is symmetric regardless of how the eye looks, you don’t have a problem. This is called pseudostrabismus and is very common. Most often with pseudostrabismus an eye appears to be turning in but occasionally one eye will appear to turn out.
The second test can be done reliably on infants six months of age or older. Have your baby sitting in front of you and have a toy or something the child will want to look at. It helps to have another person holding the baby somewhat still while you do the test. Place your hand over one eye (or have your partner do this) but don’t apply pressure. The idea is just to block the visual connection from the eye to the object. Have the child look at the object for several seconds and then move the hand away from the other eye. If the eye that was covered and then uncovered needs to whip back into alignment because it drifted away then you may have a problem. Do the same thing for the other eye.
This cover-uncover test takes some practice to do so if your child isn’t cooperating, wait a while and try again. If either eye drifts away and recovers when the hand is moved, you definitely need to have your child seen by a pediatric ophthalmologist.
Babies are born with pretty bad vision and won’t achieve 20/20 vision until as late as 7 years old, but in order to ensure the pathways that allow sight to mature, age appropriate vision needs to be there. When a young child has a true lazy eye, vision in that eye is impaired and the pathways from that eye to the visual cortex don’t grow properly. The older a child is when the diagnosis of a vision problem is made, the less likely it will be that she can make up for the lost time in laying down the pathways to the visual cortex and as a result permanent vision loss can occur.
If you see red flags when looking for a lazy eye in your child, talk to your child’s healthcare provider!