What Causes a “Lazy Eye” or Strabismus?

 Lazy eye, or Strabismus, is a growing concern for parents. It is often related to amblyopia, where one eye sees better than the other.  Most likely you know someone that has a lazy eye or had one when they were a child.  But what causes them? Are they serious? Can they be treated?

What causes a lazy eye?

When children are still developing, it’s very important to make sure both eyes are being used equally. If not, one eye may develop better than the other.  This can be related to your muscles too.  For example, if someone had an accident and was unable to use their legs for a long period of time, their muscles could atrophy.  It can be tough to get that function fully back.

Children can have different reasons for favoring one eye more than the other.  One may be that they have better vision in one eye.  We call this refractive amblyopia.  For example, if they see better with their right eye, the left one can start to be ignored.  They may even start turning their head to the left so the right eye is more front and centered.

Another reason is that their eye muscles aren’t aligned properly.  One eye may turn outward or inward.  This can be constant or part of the time. This may be because the muscles were not formed fully or the muscles tire out by the end of the day.  Sometimes, the eyes may even take turns facing forward.

Another cause of amblyopia is when one eye has an ocular condition which makes the eye unusable. We call this deprivation amblyopia.  For example, if a baby was born with a cataract, they wouldn’t use that eye much because their vision would be poorer.

The sooner treatment is started, the better the outcome.  The longer one eye is being ignored, the more chance of it losing vision.  So how can you tell if your child has amblyopia? They most likely won’t tell you if one of their eyes is blurry, and they can’t tell if their eye turns.  Watch for signs such as a wandering eye.  This is the one people tend to notice most frequently.  Also look for poor depth perception.  If they try to reach for objects and reach far past it or in front of the object, they may be only using one eye.  Another sign is a head turn as mentioned above.  The best way to prevent amblyopia, however, is with regular eye exams.

Treatments for lazy eye

• Eye patch
• Eye drops
• Prism glasses
• Muscle surgery

Let’s dig into each of these treatment options.

If a child is diagnosed with amblyopia, there are different treatments available.  Depending on visual acuity and/or amount of eye turn, patching may be option.  We would have them patch their good eye, forcing the poorer eye to work.  This may be done during specific activities, or for longer periods during the day.  If they hate wearing the eyepatch, or are too young to know any better and keep removing it, we will use eye drops.  This blurs the better seeing eye instead of the patch.

If one eye sees poorer due to being uncorrected, sometimes the simple fix is having them wear glasses or contacts.  Then both eyes are working together equally.

If their eyes still do not align, we may prescribe prism for their glasses.  This allows what they are seeing to be moved to where their eyes comfortably rest. For larger amounts of prism, muscle surgery may be a better choice.

One of the most important things a person with amblyopia can do is protect their better seeing eye!  Glasses with polycarbonate lenses that are shatterproof are a great way to do this.

If you have any concerns about your child’s vision and muscle movement, schedule an appointment.  Your eye doctor will go over which options will be the most beneficial depending on the exam results.