Amblyopia is reduced vision in one eye that results from abnormal development of the visual system during childhood, not from a structural eye disease. The brain learns to prefer input from one eye, often due to conditions like strabismus (eye misalignment) or unequal refractive error between the eyes, so the weaker eye isn’t used normally and its vision doesn’t develop properly. A very common way to treat this is to force the brain to use the weaker eye. This is typically done by patching the stronger eye for several hours a day, which encourages the visual cortex to rely on the amblyopic eye and improve its acuity. Another approach is penalization of the better-seeing eye, such as using atropine drops to blur that eye slightly, producing a similar effect of promoting use of the weaker eye. Correcting refractive errors with glasses is usually part of management, ensuring the weaker eye receives clear input. Early intervention yields better outcomes because the visual system is more adaptable in children.