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  • Updated 07.25.2020
  • Released 01.30.2003
  • Expires For CME 07.25.2023




Amblyopia is a reduction of vision produced by abnormal central visual processing. This common disorder occurs in an estimated prevalence of 2% (MPEDS 2008; 13; 27; 26). Unless treated during childhood, the loss of vision is permanent. Amblyopia therapy often requires penalization of the normal eye. The daily amount of time and the best penalization methods are unsettled and controversial. In this article, the author describes studies that investigate to quantitate the time and methods of penalization required for treatment and the ages most appropriate for their use in childhood as well as newer treatment modalities.

Key points

• Amblyopia is a reduction in visual acuity in 1 or both eyes due to refractive error, strabismus, or visual deprivation.

• Treatment of amblyopia involves treatment of the underlying cause of vision loss with or without penalization by occlusion or optical penalization.

• Amblyopia treatment is most effective at younger ages.

• Vision loss from amblyopia can be permanent if it is not treated in a timely fashion.

Historical note and terminology

Amblyopia, or lazy eye, is the reduction in the best corrected visual acuity that occurs during childhood that cannot be explained by a known structural abnormality. The term “amblyopia” is derived from the Greek amblys, meaning “blunt,” and ops, meaning “eye,” indicating a “dullness” or incomplete loss of vision rather than complete blindness (11). The early clinical understanding of this disorder can be traced to George Louis Leclerc, Comte de Buffon, who in 1743 proposed the use of occlusion of the sound eye to “force” the amblyopic eye to see better (11). The scientific study of amblyopia was advanced by the work of Hubel and Wiesel, who won the Nobel Prize in 1981 for their work demonstrating physiologic and anatomic changes in the visual system of kittens and monkeys that had been visually deprived during the critical period of visual development (49; 50). As a result of their work and subsequent studies by other investigators, the concept of amblyopia as a developmental visual disorder of childhood was established (44; 24; 39).

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