Amblyopia (lazy eye)

What is lazy eye?

In medical terminology lazy eye is referred to as amblyopia, which means “dulled” or “blunt” eye.
The truth is that the term does not truly reflect the real cause of the problem, which isn’t the eye on its own, but rather the cooperation between our brain and eye.
Amblyopia is a disorder in which there is decreased vision in one eye (usually one) that occurs in the absence of any structural defect in the eye. In amblyopia there aren’t any external signs on or surrounding the eye to indicate the problem.

How does amblyopia result in reduced vision?

Let’s go over how our eyes work in simple words.
Our eyes pick up light rays from the objects in our surroundings. These rays turn into electric signals inside a structure found at the back of our eyes called the retina. These signals then pass to the optical center in the occipital lobe of our brain, through optic nerves.
The optical center in our brain analyzes and comprehends the image our eye sees with the help of other areas in our brain. So, in practice that the process of vision is based on a mutual cooperation between our eyes and brain.
For our vision to develop properly, and for the optical center in our brain to develop properly – the information that it receives from both of our eyes must be identical and clear. That is, both eyes need to send the brain the same information.
If, for one reason or another, the information that our brain receives from one eye is clear but “blurry” from the other, our brain prefers focusing on the information that it received from the eye with the clear image and will disregard the information it received from the eye that sent an unclear image.
And that is how the eye whose image it disregards turns into a “lazy eye” leading to amblyopia.
It is important to note that the child will not be to feel or know that their eye has turned into a lazy eye, he/she will not have any specific symptoms, and this is why early recognition and diagnosis is crucial. As long as the problem is identified prior to 9 years of age, it can be treated. The earlier the child is treated, the greater the chance of full successful treatment.
Another important note – despite the absence of any official guidelines about this – we do recommend your child see an ophthalmologist for a screening examination around the age of 1 year.

What are the causes of amblyopia?

As explained above, the mechanism behind the disorder is that the brain receives clear information from one eye and unclear information from the other. Several conditions can cause this:
Strabismus – there is a two-way association between strabismus and amblyopia. Amblyopia can manifest in strabismus, turning into a sign indicating amblyopia. But the opposite can also occur, where strabismus causes amblyopia. Learn more about strabismus in infants and children here.
Refractive errors – if one eye has a high index refractive error and the other eye has a low index, the eye with the high index can become a ‘lazy eye’.
A congenital or acquired anatomical disorder such as cataract or retinal detachment.

What is the prevalence of amblyopia?

This is a relatively prevalent disorder, found in about 3% of the general population.

How is amblyopia treated?

It is important to treat it as early as possible, at a stage where we are still able to “exercise” the part of our brain that was deprived of a clear image. What I’m trying to say is that if your left eye is the “good” eye, the one that is able to send a clear image to the brain, and the right eye is the “lazy” one that sends blurry information, we need to try and exercise the right eye and by doing so to strengthen the part of the brain that has been affected.

How can we “strengthen” or “exercise” the brain?

There are several different ways to do this. They all have one thing in common: to isolate the lazy eye and exercise it on its own while the “good” eye is covered. That way, you force the brain to use the lazy eye and improve the corresponding part of the brain that gets its information from that eye.
The first step is to get prescription lenses, if needed, to improve vision in the lazy eye.
Next, you need to cover the stronger eye with an eye patch (one made especially to cover the lenses) for a few hours per day.
The number of hours per day that the eye needs to be covered, and the length of time that the child will be asked to do this will be set by their ophthalmologist and will depend on the child’s age, the severity of the disorder, etc. The treatment is individualized to the child and their condition.
Sometimes eye drops that blur the vision in the “good” eye are also used.

Finally, a relatively new and innovative treatment that is not commonly used yet but will probably become more popular in the coming years, is the use of special lenses that have different filters.
The child is typically asked to watch movies while wearing these lenses. The filters reduce the quality of the image in the good eye and by doing so strengthen the weaker eye.
That means, the concept behind all the different treatments is similar.

In summary, amblyopia is a condition that must be diagnosed and managed at an early stage in childhood to prevent permanent reduction in vision in one of the eyes, a reduction that cannot be repaired afterwards.
This is one of the reasons why it is important for children to undergo routine examinations at the ophthalmologist, as mentioned in the chapter “Everything you need to know about children’s vision” found in the link here.

Good luck!