Anisometropia
WHAT IS ANISOMETROPIA?
Anisometropia means the two eyes need different glasses prescriptions. This makes one eye blurrier than the other without glasses. It happens because one eye is shaped a little differently. This can cause one eye to be more farsighted (hyperopia), more nearsighted (myopia), or have more astigmatism than the other. See more about the different types of refractive error (need for glasses) here.
WHY IS THIS A PROBLEM FOR MY CHILD?
When one eye is blurrier than the other, the brain will use the eye that sees better. The blurry eye gets ignored and doesn’t learn to see well. This is called amblyopia. If amblyopia is not treated at an early age, the blurry eye can end up with permanent poor vision.
HOW DO I KNOW IF MY CHILD HAS ANISOMETROPIA?
Most children with anisometropia don’t show symptoms. They keep both eyes open and don’t complain, because the stronger eye makes up for the weaker one. Unless the eye starts to drift in or out, you likely won’t notice it at home. Anisometropia is usually found during a school vision screen, a pediatric checkup, or an eye exam. Don’t feel bad if you didn’t notice a problem — it is usually picked up during routine vision testing, not by parents at home.
WHEN SHOULD a CHILD BE CHECKED?
Anisometropia is best found early, ideally by age 3–4 years. Regular vision screening at the pediatrician or school helps catch it. If you are worried about your child’s vision at any age, ask your pediatrician or a pediatric eye doctor for an exam.
WHAT IS THE TREATMENT?
The first step is giving the right glasses (or sometimes contacts). Glasses must be worn as instructed, usually all day. Starting glasses early can prevent the need for other treatments. If glasses alone don’t fix the problem, the child has amblyopia and the brain needs help to use the weaker eye. This can be done by:
- Patching the stronger eye
- Using a drop to blur the stronger eye
- Using filters on glasses
- Newer treatments (such as special video devices) that make the brain use both eyes together
These amblyopia treatments help the brain practice with the weaker eye so vision improves. Regular follow-up visits are important to see how vision is improving and to change treatment if needed.
WILL anisometropia EVER GET BETTER?
Children’s prescriptions often change as they grow, but the difference between the two eyes may stay. Treatment for poor vision in one eye works best when started early. How well vision improves depends on the child’s age when treatment begins, how closely the plan is followed, and how the prescription changes over time. Some kids may outgrow their need for glasses, but many will need glasses for life.
Speak with your eye doctor (ophthalmologist) if you have more questions about anisometropia.
More information:
Updated 09/2025
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