What's New in Eye Care

We all know someone with a lazy eye. But what exactly does the term mean?

When most people think of lazy eye, they think of an eye that wanders. The medical term for an eye that is not lined up properly is strabismus. When an eye turns inward when it is supposed to be looking straight, that is called esotropia. When an eye turns outward, it is called exotropia. A strabismus that is present all the time is called constant. When it is only there some of the time, it is termed intermittent.

But an eye can be a lazy eye even if it is always lined up!

This is because, for eye doctors, a lazy eye is an eye that does not see well, even with the correct prescription, and even though there is nothing physically wrong with the eye. The medical term for this condition is amblyopia. Not only does amblyopia reduce vision, but it can also have many other educational and social impacts.

But if there is nothing wrong with the eye, why doesn’t it see well? 

The answer is that amblyopia is a brain problem. It usually develops in early childhood, when some other factor causes an eye to not see well. As a result, the information that that eye sends to the brain is not as detailed as the information that the other eye sends. The brain then learns to rely on the good eye. This means that even if the underlying problem with the amblyopic eye is corrected, the vision in that eye may not improve as expected- because the brain has already learned to ignore that bad eye and use the good one.

The most common causes of amblyopia include:

1. Strabismus. When an eye is turned, it can cause double vision. This is very difficult to adapt to, and so the brain often “turns off” the deviated eye. In other words, it learns to rely on the eye that is aligned and ignore the one that is turned.
2. Refractive error. If an eye is very near-sighted, very far-sighted, or has a significant amount of astigmatism, then it produces a blurry image. When it sends that blurry image to the brain, the brain learns that it is getting better information from the other eye, and so, again, it learns to ignore the eye with the blurry image.
3. A physical defect that obscures the vision in early childhood. The most common causes are cataracts and eyelids that droop far enough to cover the pupil.

In all of the above cases, one or both eyes has a blurry image of the world. As a result, the brain learns to ignore it and rely on the good eye. The problem with amblyopia is that even when the problem is corrected with surgery or glasses, the vision often does not improve as much as expected. The brain has learned to ignore that eye, and so it does not “know” that the eye is providing better information after the treatment.

So, how do we treat amblyopia?

The traditional treatment has been to temporarily blur the good eye. This can be done with eye drops or with a patch. Both treatments force the brain to learn to use the bad eye again.

But now there is a new treatment for amblyopia: Luminopia One. The luminopia system uses technology to control the visual information that the brain receives from each eye, thus teaching the brain to use the poorer eye. 

All the patient has to do is put on a Virtual Reality Mask, prescribed by the eye doctor, and then sit back and watch a movie or play a video game!  Finally, technology that makes treatment enjoyable! Your kids’ friends may start wishing that they had amblyopia too!