Amblyopia, or lazy eye, refers to a unilateral or bilateral decrease of vision, in one or both eyes, caused by abnormal vision development in childhood or infancy. It is a common vision problem in children and is the leading cause of decreased vision among children. Most vision loss is preventable or reversible with the right kind of intervention.

Signs and symptoms

The history should address the following:

• Previous history of patching or eye drops
• Past compliance with these therapies
• Previous ocular surgery or disease
• Family history of strabismus or other ocular problems

The physical examination should include the following:

• Assessment of visual acuity
• Testing for crowding phenomenon (difficulty in distinguishing optotypes that are close together)
• Specific testing measures in preverbal children
• Evaluation of contrast sensitivity
• Neutral density filter testing
• Assessment of binocular function
• Detection of eccentric fixation
• Cycloplegic refraction
• Sensory testing
• Motility examination

A full eye examination must be performed to rule out ocular pathology.

The most important causes of amblyopia are as follows ^{[1, 2]} :

• Anisometropia or refractive errors
• Strabismus
• Strabismic anisometropia
• Visual deprivation
• Organic lesions

  Diagnosis

  Imaging studies that may be helpful when the ocular examination is normal and suspicion of an organic cause exists include the following:

  • CT
  • MRI
  • Fluorescein angiography (to assess the retina)

  Other tests that may be helpful in diagnosis include the following:

  • Electrophysiologic studies (investigational; differences noted are controversial)
  • Spectral-domain optical coherence tomography (SD-OCT)

    Management

    First, rule out an organic cause and treat any obstacle to vision, such as cataract or ptosis, if clinically significant. Next, treat anisometropia and refractive errors. Then, initiate occlusion therapy (to force the use of the amblyopic eye) or penalization therapy.

    Occlusion therapy

    The following are general guidelines for occlusion therapy:

    • Patching may be full-time or part-time
    • Always consider lack of compliance in a child when visual acuity is not improving. Question patients regarding peeking
    • In addition to adhesive Band-Aid–type patches, consider the use of opaque contact lenses, occluders mounted on spectacles, and adhesive tape or Bangerter foils on glasses
    • Establishing whether the vision of the better eye has been degraded sufficiently with the chosen therapy

    Additional treatment options include the following:

    • Atropine penalization therapy (also used for maintenance)
    • Optical blurring through contact lenses or elevated bifocal segments

    Treatment of strabismus generally occurs last. The endpoint of strabismic amblyopia is freely alternating fixation with equal vision. Surgery generally is performed after this endpoint has been reach