What is what: lazy eye or strabismus?

There are two visual disturbances that usually occur during childhood and are often confused or misunderstood. They are amblyopia, better known as “lazy eye”, and strabismus. We explain what each one is, how to differentiate between them and what is the most appropriate treatment in each case.

What is lazy eye

Amblyopia or lazy eye is a vision impairment caused by poor coordination with the brain. Although there is no disease that hinders the visual capacity of the eyes, the brain receives poorer quality visual information from one of them, so it gives preference to the eye that sees better. This causes the other eye not to be stimulated or work hard enough and it ends up becoming “lazy”.

Amblyopia or lazy eye usually develops at a very early age and is the leading cause of childhood vision loss. For this reason, it is essential to have an early eye examination by an eye specialist in order to detect this disorder and correct it as soon as possible.

What is strabismus

Strabismus is an alteration in the alignment of the eyes that causes them not to look simultaneously at the same point. It can occur in children as early as 6 months of age (known as congenital strabismus) or appear later due to different causes.

It is very important to treat it as soon as possible to avoid amblyopia or lazy eye. Therefore, if an ocular deviation is detected, it is necessary to go for an ophthalmologic check-up with a strabismus specialist.

Similarities and differences between lazy eye and strabismus

The terms amblyopia (or lazy eye) and strabismus are often confused and sometimes used interchangeably to refer to both. As we have seen, lazy eye consists of low vision in one or both eyes, which causes the brain to give preference to the one that sees better and ignore the other, which becomes “lazy”. Strabismus, on the other hand, is the misalignment of the eyes that causes them not to look at the same direction.

Although they are different disorders, lazy eye is in many cases a consequence of strabismus. This occurs because the person affected by strabismus gives preference and keeps straight the eye that is easier for him to focus on images and gets used to use only that eye. Meanwhile, the deviated eye does not work, so it runs the risk of becoming “lazy”.

Treatment of lazy eye

Lazy eye or amblyopia can only be treated during childhood, so the earlier it is detected, the better the results will be. In fact, after the age of 8, the success rate of treatment begins to decrease, although there are some cases in which improvements have been achieved up to the age of 15.

Lazy eye cannot be treated with surgery, but is usually corrected with the use of glasses, eye patches or medication. Eye patching forces the child to use the weaker eye in order to correct low vision. It is also possible to use glasses that blur the vision of the preferred eye to force the weaker eye to work properly. This process can take weeks or months. Once the patient has gained vision in the weaker eye, the patch can be removed and in some cases the patient may continue to wear it part-time for some time to maintain good vision.

Treatment of strabismus

Strabismus, on the other hand, can be treated with surgery, although in some cases the first treatment may be the use of glasses, sometimes accompanied by occlusions. If glasses are not enough, medication can be applied in order to relax the muscles. And finally, if this is not enough, surgical treatment may be used.

Strabismus surgery consists of weakening or strengthening the eye muscles to modify the alignment of the eye in order to make it parallel. Contrary to what was believed until recently, strabismus can be successfully operated on at any age, even in adults. Even so, surgery will not correct a possible amblyopia or lazy eye that the patient may have as a consequence of childhood strabismus.