Is it Lazy Eye or Strabismus?

Sometimes, it’s hard enough to tell if your two-year-old has a tummy ache or is just hungry – how can you tell if he or she has an eye disorder?

“Parents of small children are understandably confused about the difference between ‘lazy eye’ and misaligned eyes. It can be tricky to know what’s going on with children’s vision. However, there are things you and your pediatrician can watch for,” says Dr. Ta Chen P. Chang, a pediatric ophthalmologist at Bascom Palmer Eye Institute, part of the University of Miami Health System.

Dr. Chang’s guidance helps parents who suspect something is amiss with their child’s vision. It’s timely advice for Children’s Eye Health and Safety Month this August.

Lazy or wandering?

It’s easy to confuse lazy eye (amblyopia) with misaligned eyes (strabismus) or, as they’re commonly known, crossed or wandering eyes. A lazy eye is when an eye has poor vision because it’s not working in sync with the brain. As the brain relies on the stronger eye, the other eye becomes weak or “lazy” because it’s not being used. As the eye weakens, it “wanders” – up, down or sideways. This is known as strabismus. Though more common in one eye, both eyes can be affected. On the other hand, the eyes can also become misaligned because of poor vision, uncorrected need for glasses, or an imbalance between the muscles that move the eyes. Lazy eye can lead to misaligned eye, and vice versa.

“Amblyopia impairs depth perception and can cause blindness, so it’s critical to catch it early. Treatment is vital, either with eyeglasses or patching the working eye to strengthen the lazy eye. If you wait until the child is older, treatment is much less effective,” says Dr. Chang.

Causes and symptoms

What causes some children to develop vision problems? The answer may lie in your family tree. While strabismus runs in families, it’s also more common in children with Down syndrome, hydrocephalus, cerebral palsy or brain tumors. Amblyopia can be caused by eye diseases, one eye that doesn’t focus as well as the other, and in children who are moderately to severely nearsighted, farsighted or have high astigmatism.

Amblyopia and misalignments happen more often in infants and small children, but older children and some adults can develop these disorders. The good news is that most alignment issues improve with correct treatment.

It may seem easy to spot a child with a lazy or misaligned eye, but it’s not always apparent, especially in the early stages. Here’s what to look for:

  • Eyes that don’t move together
  • One eye that turns in, out, up or down
  • Poor vision that gets worse
  • Double vision*
  • Poor depth perception
  • Trouble reading
  • Headaches

*Sudden double vision may mean a serious neurologic disorder. Seek immediate medical attention.

The all-important exam

Fortunately, you don’t have to figure this out on your own. “A pediatrician should examine your baby’s eyes throughout the first year of life. If your child’s eyesight appears healthy, they need a thorough eye exam by their fourth birthday and every two years after that” Dr. Chang says.

If you or your doctor spot any of the signs mentioned above, “See a pediatric ophthalmologist as soon as possible. We’re trained to diagnose and correct these conditions early, when treatment is most effective.”

If your child already has strabismus, eye muscle surgery can improve the function and appearance of the eyes. For most patients, it is an outpatient surgery with a short recovery.

Beyond possible vision loss, untreated lazy or misaligned eyes can lead to academic and social setbacks. For all of these reasons, the U.S. Preventative Task Force takes vision screening one step further and recommends that it begin at preschool age.

“As an ophthalmologist, I see many children who struggle to reach their full potential because of vision problems. That never needs to happen with amblyopia and strabismus – two of the most treatable conditions, when caught early,” says Dr. Chang.


Nancy Moreland is a contributor to UMiami Health News. She has written for several major health care systems and the Centers for Disease Control and Prevention. Her articles also appear in the Chicago Tribune.