Lazy eye causes and treatments

Lazy eye or amblyopia results when an eye cannot be corrected, with glasses or contacts, to see 20/20.

What causes lazy eye?  The two most common reasons are refractive amblyopia and strabismic amblyopia.

Let’s discuss refractive amblyopia first.  If an eye has a refractive error, this simply means that it needs an eyeglass prescription to see clearly.

Here is an example.  A young child has no eyeglass prescription in his right eye and sees clearly out of this eye.  His right eye focuses the images very crisply on his retina.  His left eye, however, has a moderate to high amount of farsightedness.  Most of what he sees is blurry out of this eye.  This is because the eye sends a blurry image back to his retina.

This child must use his right eye to see detail in his early years.  Over a few months and years his brain will allow much more development of his right eye while restraining the development in his left eye.  The result is a strong, healthy retina in the right eye but weak retinal development in his left eye.  Therefore a lazy eye develops.

Strabismic amblyopia is the other most common type of lazy eye.  Strabismus means that an eye is turned inward or outward.

Here is an example.  A different young child has a right eye that accurately points to each image that he wants to look at.  Therefore, his retina receives an accurate image of each object.  This child’s left eye, however, drifts outward much of the day.  When this boy wants to look at an object his left eye is not able to align on it properly so it points to another object nearby.

Unfortunately, now his brain receives conflicting images.  The picture from his right eye is the picture that he wants to see but the picture from his left eye is not the correct picture.  His brain will see two different pictures, which causes double vision for him.  To avoid this, the child’s brain will “turn off” his left eye much of the day.  Like the child above, the right eye retina develops normally but the left eye’s retina does not develop nearly as well.  Again, a lazy eye develops.

How can you treat lazy eye?

We treat lazy eye by stimulating the retina in the weaker eye.

Years ago, this meant patching the “good eye” and forcing the weaker eye to work.

In modern medicine we usually use a combination of techniques to achieve best results in treating lazy eye.  These strategies can include patching the stronger eye for part of the day.  This time ranges from 2 hours to 6 hours depending on the severity.  It can mean vision therapy to stimulate the lazy eye and promote development in that retina.  And it can include using eye drops in one eye to help develop the weaker eye.

In my office I believe in totally treating lazy eye by combining as many of these tools as possible.  We only have a certain window of time during your child’s development to treat lazy eye, so we must be aggressive in treatment.

The key is that we diagnose lazy eye as early as possible.  This is the best tool we have in fully treating lazy eye.