Lazy eye (amblyopia) is reduced vision in one eye caused by abnormal visual development early in life. The weaker - or lazy - eye often wanders inward or outward.Amblyopia generally develops from birth up to age 7 years. It is the leading cause of decreased vision among children. Rarely, lazy eye affects both eyes.Early diagnosis and treatment can help prevent long-term problems with your child's vision. The eye with poorer vision can usually be corrected with glasses or contact lenses, or patching therapy.