WHAT IS AMBLYOPIA?
Amblyopia, popularly known as "lazy eye", is a visual disorder characterized by vision and visual skills deficiency in one eye that did not develop properly during childhood. It usually occurs in early childhood, during the development of vision: one eye develops properly and the other one does not, because of some problems occurred during pregnancy, at birth or later in infancy.
Amblyopia normally affects one eye, however bilateral amblyopia may also appear in both eyes when they fail to reach normal vision. This condition is relatively common, affecting 4 out of 100 people. Amblyopia can be corrected only if detected and treated in infancy or early age. Among children from 9 to 12, the recovery is more complex or even permanent. Parents should be much aware of this threat to their children's visual health.
In most school medical checkups that are performed on children, there is a section specifically designed to test the vision. If abnormalities in visual acuity are detected while screening, the child must be referred without delay to the ophthalmologist. It is advisable that children aged of 3 get their eyes screened, or even sooner if there are visual disorders within the family.
NORMAL DEVELOPMENT OF VISION
Although newborns are able to see, the vision will improve over the first month of life while increasing the use of the eyes. During the early years of childhood, the visual system is in a state of flux. Vision continues its process of evolution with the proper use of it. However, if the eyes are not used because of any disease process or other causes (cataract, corneal scarring), visual skills decrease. After the first nine years of life, the visual system has been completed; hence, it will be very difficult to gain any visual skill that has not been naturally reached at that time.
To achieve normal visual acuity, a proper and balanced development of both eyes is required. Some people, whose vision is limited to one eye, do not have access to some professions. Also, we shall consider that vision may be affected later in lifetime due to an accident or illness. Thus, it is essential that the other eye is kept healthy as well. For this reason, the earlier amblyopia is detected and treated, the more successful the visual outcome will be.
CAUSES AND SYMPTOMS
Amblyopia is caused by an alteration that affects the normal development of vision in the evolution's process or learning period. This often occurs when there is a misalignment between the two eyes, a disorder called strabismus. Amblyopia can also happen when one eye does not focus as well as the other one does, because it has a higher degree of hyperopia, myopia or astigmatism. The fact of focusing badly can make the eye stop working and becoming amblyopic or lazy, and causing dependency of the better seeing eye. An impaired congenital cataract (cloudy areas in the lens that prevents light rays from focusing clearly on the retina), can lead to amblyopia. Any factor that hinders or prevents a clear, sharp image, focused on the eye, can lead to the development of amblyopia in childhood. Children may also inherit from their parents some conditions, which may cause them amblyopia. Therefore, an ophthalmologist should screen children with a family history of amblyopia or strabismus at an early age.
It is important to note that the treatment for the condition that causes amblyopia does not cure the disease alone. After treating strabismus, correcting blurred vision with eyeglasses or removing a cataract, amblyopia must be treated separately.
Often amblyopia is not detected because a child may not be aware of having an eye that sees less than the other. Unless the child, affected by amblyopia, has strabismus or other obvious abnormal signs, there is no way for parents to track down this condition.
The treatment of amblyopia is focused to use the weaker eye. This is done usually by putting a patch in the "good" eye for a few weeks or months. If necessary, eyeglasses to correct blurred vision or unbalanced focusing will be used. Sometimes amblyopia is corrected by blurring the vision in the "good" eye by means of a drug (eye drops) or lenses to force the child to use the amblyopic eye. If another abnormal condition is detected such as cataracts or strabismus, the ophthalmologist shall decide the medical or surgical treatment required to correct the cause of amblyopia. Therefore, eye patching is the first method most often used to correct amblyopia and in most cases, is complemented by visual exercises. An excessive or uncontrolled patching might worsen the vision of the patched eye, so it is very important to follow the instructions given by the eye care expert.
If amblyopia is not treated, several severe problems may happen: the amblyopic eye may develop a serious and permanent disorder: depth perception can be greatly reduced, and if the good eye suffers a disease or an accident, a lifetime of poor vision and no possibility of improvement may be the result.
The eye care professionals can give the family instructions on how to treat amblyopia, but it is the parents' responsibility to carry out this treatment. Children generally do not like to have their eyes patched, but parents must convince their children to do what is best for them. Often, the success of treatment depends on the interest and the involvement of the family members, and their ability to gain their children's cooperation. In most cases, parents play an important and key role in solving their children's amblyopia.
VISION LOSS CAN BE WIDELY PREVENTED
A successful treatment is dependent upon on how severe the amblyopia is and how old the child is when treatment is begun. If the problem is detected and treated early, most amblyopic children will improve their vision, but treatment may be extended till the age of 9 or beyond. If amblyopia has been detected for the first time after the age of 8 or 9, treatment is usually not as effective. Yet, when amblyopia is caused by refractive disorders (myopia, etc.), it can be treated quite successfully in young adults.
1. Good vision develops in the first years of life as a result of normal and proper use of the eyes. An eye, which has not developed properly from the first weeks of life until the age of 9, will not achieve good vision and will become an amblyopic eye.
2. Few causes of amblyopia have significant symptoms to be easily noticed. Thus, amblyopia must be detected by eye screening.
3. The most important causes of amblyopia are: strabismus, refractive disorders (hyperopia, myopia or astigmatism), and eye pathology like cataracts.
4. Early detection and correct treatment followed by an ophthalmologist, as well as a strict supervision of the child's behavior by the parents, are the right combination to succeed in beating amblyopia.