Lazy eye or amblyopia: symptoms, causes and treatments

Redazione Emianopsia
The Editorial Staff of Emianopsia
4 minutes
The lazy eye or amblyopia is a reduced visual ability of an eye compared to the contralateral eye.
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    We talk about lazy eye or amblyopia when one eye does not work as well as the other. The term amblyopia comes from the Greek word “ἀμβλύς” (lazy/weak) and the root “ops” (vision). This condition can be diagnosed when only one of the two eyes has some defect. The period in which our brain learns to read and process the visual stimuli ranges from the first months of life up to 5-6 years.

    Vision is a phenomenon of critical reading of the brain (with respect to the stimuli that we receive) through the eyes; therefore, just as we learn to walk and speak, sight is also a skill that we learn to use.

    The lazy eye or amblyopia must be corrected within this period of “formation” (5-6 years) to take advantage of the neuroplasticity of our nervous system, particularly active during the first years of life. In this way, we can work on correcting the amblyope eye, as well as correlated issues. It is essential to request an eye examination within 5 years to prevent this type of problem.

    Here is a brief overview published by Maria Elisa Scarale that gives an overview of this issue.

    Symptoms of amblyopia

    The signs that can alert a parent to the onset of this problem are:

    • reduction of the ability to perceive depth: the depth of field can only occur correctly when both eyes work well (since it depends on the overlapping of both images perceived by the eyes)
    • small eye movements that arise during fixation activity: in this case one of the two eyes gets tired and begins to deviate outwards or inwards.

    What are the causes of lazy or amblyopic eye?

    Among the defects that can lead to this type of problem we find:

    • asymmetrical hypermetropia: the subject gives priority to the image it receives from the dominant eye (with less accentuated hypermetropia). In this way the more hypermetropic eye tends to become amblyope
    • different gradation between the two eyes: in this case, the patient tends to only make use of the best eye
    • astigmatism: one eye will send an image more blurred than the other so, in this case too, priority will be given to the data received by the “stronger” eye
    • squint: in this case the brain filters images coming from the deviated eye
    • In any condition in which the eye is unable to see (amblyopia from deprivation), such as: congenital ptosis (the eyelid remains lowered for various reasons), congenital cataract, or an alteration of the cornea, this issue is treated surgically.

    The diagnosis

    This disorder is very frequent in children, but it is more difficult to diagnose promptly (especially in the absence of an obvious squint), making it necessary to resort to an eye examination within the first 3 years of the child’s life.

    You should contact your ophthalmologist to detect the presence of this problem, remove any anatomical obstacles, and to identify and treat this problem.

    The figure of the orthoptist, however, is responsible for visual rehabilitation. Considering the patient’s profile (age, needs and severity of the problem), the orthoptist proceeds to the implementation of a personalized therapeutic program.

    The orthoptist proceeds to the orthoptic evaluation of: 

    • ocular motility
    • eye alignment
    • perception of colors
    • contrast sensitivity.

    Is it possible to correct a “lazy eye” in adulthood?

    After the sixth year of life it becomes increasingly difficult to correct amblyopia, but it is not impossible. The difficulty of the intervention depends on the degree of depth of this problem.

    Occlusive therapy

    There are, in fact, cases of adult patients who were able to restore proper functioning of the eye with the appropriate therapy.

    In this case we talk about occlusive therapy: the dominant eye is covered with a bandage or an adhesive patch for a period of time that varies depending on the level of severity of the amblyopia and the age of the subject.

    During rehabilitation, the person being treated by the orthoptist will have to carry out an activity (agreed or at will) at close range, implementing close vision. In this way we “force” the lazy eye to work, training it and guiding it towards a full rehabilitation.

    A intervalli regolari, l’ortottista valuta i progressi del paziente, e, eventualmente, applica delle modifiche al trattamento.

    At regular intervals, the orthoptist evaluates the patient’s progress, and, if necessary, applies changes to the treatment.

    • severity of the disorder
    • presence of squint
    • patient collaboration
    • age of the patient at the beginning of therapy.

    Refractive surgery

    In cases where occlusive therapy is not sufficient to bring about a significant improvement in this problem it is necessary to resort to surgery. With refractive surgery, we can apply a strong correction to just one eye, which would have been impossible with contact lenses or glasses. The patient can even see well with the eye defined amblyope.

    In other cases, still resorting to refractive surgery, we can eliminate the underlying defect. In this case we can see a huge improvement in the overall visual quality of the patient, and a better perception of depth.

    Redazione Emianopsia
    The Editorial Staff of Emianopsia
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