Amblyopia is a unilateral visual impairment that is usually seen in young children. It is often referred to as a “lazy eye”. The images transmitted by this eye are ignored by the brain, which leads to a progressive loss of vision. This can be corrected if it is treated early, usually before the age of eight. The management of amblyopia in adults is much more difficult.
What is amblyopia?
Definition of amblyopia
Amblyopia is characterized by a difference in visual acuity between the two eyes. One eye is called the “lazy eye”: the images transmitted by this eye are of insufficient quality to be processed by the brain. The brain will ignore these images, a phenomenon that will gradually lead to a progressive loss of vision. This deterioration of vision can become permanent if it is not treated in time.
Types of amblyopia
It is possible to distinguish several forms of amblyopia. The most common is functional amblyopia. It is a visual defect during childhood. The brain ignores the images in one of the two eyes, which affects vision.
There are other forms of amblyopia such as organic amblyopia which is related to an ocular lesion. This form is rare. This is why the medical term amblyopia often refers to functional amblyopia.
Causes of amblyopia
Three major causes have been identified:
- misalignment of the eyes, a phenomenon that is more commonly called strabismus;
- focusing problems, or refractive disorders, which can manifest themselves by hyperopia (blurred perception of nearby objects) or by astigmatism (deformation of the cornea);
- an obstruction of the visual axis between the surface of the eye and the retina which can occur in particular during a congenital cataract (total or partial opacity of the crystalline lens present from birth or appearing in the first months of life).
Diagnosis of amblyopia
Amblyopia is detected by screening for visual disorders. Early detection is essential because management depends on it. Amblyopia in adults is much more difficult to manage than when it is diagnosed in children.
Visual screening is based on visual acuity tests. However, these tests are not applicable or relevant in very young children. They may not be able to speak or give an objective answer. Screening can then be based on pupillary reflex analysis. This can be done by photoscreening: a recording of pupillary reflexes with a camera.
People affected by amblyopia
Amblyopia usually develops during visual development before the age of 2. It is estimated that it affects about 2 to 3% of children. Amblyopia can be corrected if caught early, usually before the age of eight. Beyond that, amblyopia in adolescents and adults is more difficult to manage.
Risk factors for amblyopia
Certain factors may favor the development of amblyopia in children:
- hyperopia, considered the main risk factor;
- an asymmetric refractive error
- a family history of refractive errors
- Trisomy 21;
- a motor disability in the brain;
- neuromotor disorders.
Symptoms of amblyopia
Signs in young children
Amblyopia generally manifests itself in children in their first few months. During this period, it is often difficult to (re)understand the symptoms experienced by children. They are not yet able to express their feelings clearly. In addition, they are not aware that they have a visual disorder. However, there are signs that may suggest that the child has amblyopia:
- the child squints;
- the child covers one eye;
- the child’s eyes look in different directions.
Symptoms in older children
From about three years of age, vision problems are easier to detect. The child may complain of a vision problem: a blurred perception of objects near or far. In any case, a medical consultation is recommended if there is any doubt about the symptoms of amblyopia.
Symptoms in adolescents and adults
The situation is similar in adolescents and adults. Amblyopia is usually seen with unilateral vision loss.
Treatments for amblyopia
The treatment of amblyopia consists of stimulating the brain to use the lazy eye. To achieve this, several solutions can be used such as :
- wearing glasses or contact lenses ;
- the application of bandages or eye drops that prevent the use of the unaffected eye and thus force the mobilization of the affected eye;
- Cataract extraction if the situation requires it;
- treatment of strabismus if necessary.
There are no solutions to prevent amblyopia. However, it is possible to prevent complications by regularly checking your child’s vision with a health professional. Preventing complications also means following medical recommendations after the diagnosis of amblyopia.