Amblyopia refers to the partial or total loss of vision in one eye, arising from conditions that disrupt normal visual development. Such conditions include strabismus, where the eyes are misaligned either crossing inward (esotropia) or turning outward (exotropia). Another cause is a significant difference in refractive error between the eyes, such as from farsightedness or astigmatism. Less frequently, amblyopia can result from ptosis (drooping of an eyelid), diseases that block light from entering the eye, or eye injuries in young children.In cases of amblyopia, the brain prioritizes one eye, neglecting the other. This lack of stimulation hinders the normal maturation of visual brain cells. Amblyopia is the leading cause of monocular blindness, which is partial or complete blindness in one eye, affecting 2 to 3% of children in the United States.To treat strabismus, surgery might be needed to correct the imbalance in eye muscles. Severe refractive errors should be addressed with glasses, contact lenses, or possibly LASIK surgery. A traditional treatment for amblyopia involves wearing an eye patch over the dominant eye. Another method is using eye drops to temporarily blur the vision in the stronger eye. Weekend atropine has been shown to improve vision to a similar degree as daily atropine in treating moderate amblyopia.The term "amblyopia" is sometimes mistakenly used interchangeably with other conditions. "Amblyopia" derives from the Greek "amblys," meaning blunt, dull, faint, or dim, and "-opia," meaning eye, thus literally translating to "dim vision."See also: Anisometropia; Nocturnal amblyopia; Strabismus.