La amblyopia, also known as lazy eye or lazy eye, It is a condition that involves a partial reduction of vision in one of the eyes.
En Área Oftalmológica Avanzada We tell you what are the types of amblyopia that can occur.
What is amblyopia or lazy eye?
La amblyopia is a visual pathology in which, although eye health is correct, the brain does not correctly process the image it receives from one of the eyes.
This effect occurs because the brain "favors" one eye when it receives a sharper image than the other.
It usually affects one eye, but there are cases in which an bilateral amblyopia as there are important differences in refractive defects between both eyes. This occurs especially in severe cases of astigmatism in children.
Lazy eye has an incidence of 3 out of 100 children, being the most common cause of vision loss in childhood. However, cases of amblyopia are also diagnosed in adults.
How does lazy eye occur?
This problem occurs because the brain cells responsible for the vision of the affected eye not developed enough.
In most cases it is due to visual defects that have not been detected and / or corrected during childhood.
There are other possible causes, such as a congenital cataract or squint.
Types of amblyopia
different types of amblyopia, according to the cause that generates it:
Strabismic amblyopia
It is the most common type of amblyopia. La strabismic amblyopia occurs when there is a case of strabismus and the brain removes the image from the deviated eye so that poor vision does not occur.
In this way, the child ends up using only one eye, while the other ends up developing amblyopia.
Anisometropic amblyopia
Anisometry is an eye disease that refers to when there is a high difference of diopter between the two eyes. Thus, anisometropic amblyopia is amblyopia that occurs due to a significant difference in refraction between the two eyes.
This causes that the eye with the greater refractive error has more blurred vision. When this happens, the brain suppresses the image to give preference to the less affected eye.
Refractive amblyopia
If you have a refractive defect in both eyes of a certain importance, the image formed by the eyes can be so blurry as to produce amblyopia.
If there is a prior refractive effect of some importance, the image that affects both eyes can become so blurred that it leads to amblyopia.
Deprivation amblyopia
If there is a previous defect that forces the patient to cover the eye totally or partially, the light does not reach the right way retina and the formed image is affected.
This type of amblyopia is the most serious, so it is essential to start treatment as soon as possible.
Deprivation amblyopia is due to the fact that the normally transparent tissues of the eye cease to be so due to congenital cataracts or defects in the structure of the cornea.
It can also be caused by a congenital ptosis, since one is born with a drooping eyelid to the point that it covers the light that should enter through the eye.
Causes of each type of amblyopia
All the causes of each type of amblyopia
- Striabic amblyopia: strabismus, which is a misalignment in the eyes.
- Anisometropic amblyopia: anisometropia, that is, important differences in refraction between the two eyes.
- Refractive amblyopia: considerable refractive defect in both eyes.
- Deprivation amblyopia: lack of transparency in the ocular tissues (due to congenital cataracts or problems in the structure of the cornea) or congenital ptosis.
How to evaluate lazy eye?
It is not easy to recognize amblyopia, since is usually asymptomatic. But the following tests can be performed for your diagnosis:
Visual acuity measurement
Consists in measure the size of the smallest object it recognizes the child, who according to his age will have to reach a visual acuity minimal in both eyes equally.
cover test
Through the cover test we check that the eyes are correctly aligned. This test is done in two parts:
- Cover-uncover: one of the two eyes is covered and it is discovered, observing the movements of the two eyes.
- Alternating cover: he covers one of his eyes for a few seconds, moving quickly to the other.
Stereopsis or stereoacuteness
Through this test it is analyzed if the patient has three-dimensional vision. For this, it is necessary for the brain to receive clear images from the two eyes, with these perfectly aligned, and for a certain time.
When a stereo vision is achieved, it means that the process of visual maturation has been completed.
Checking the subjective refractive state
Is assess refraction in both eyes, to know if there is a difference from one to the other.
To perform it, it is necessary that the child has turned 3 or 4 years old, or that he or she is already capable of collaborating in the test.
Objective refractive status check
This is a test that is done to children under 3 years of age, because their ability to collaborate is limited.
It is done to check the refractive state of the eyes, administering a few cycloplegic drops to dilate the pupil, to eliminate any possibility of focusing.
In this way it is possible to know objectively what is the real state of refraction of the patient.
You can also practice a retinoscopy or self-refraction.
Eye health check
In this case the ophthalmologist makes a eye scan through a biomicroscope or slit lamp. This examination allows the pediatric ophthalmologist to verify that eye health is preserved. In some cases, you can also apply a cycloplegic drops to analyze the fundus.
En Área Oftalmológica Avanzada we are experts in the diagnosis and treatment of all types of amblyopia. If you have doubts about this topic, you just have to contact us. We will be happy to help you!
