Chronic pain: Pain (an unpleasant sense of discomfort) that persists or progresses over a long period of time. In contrast to acute pain that arises suddenly in response to a specific injury and is usually treatable, chronic pain persists over time and is often resistant to medical treatments.
Common causes of the condition include: 1  Muscle imbalance (strabismus). The most common cause of lazy eye is an imbalance in the muscles that position the eyes. 2  Difference in sharpness of vision between the eyes (refractive anisometropia).
An eye focusing problem that is unrelated to changes in the lens of the eye due to aging. Amblyopia. Also known as lazy eye, the loss or lack of development of clear vision in just one eye not due to eye health problems. Eyeglasses or contact lenses can't fully correct the reduced vision caused by lazy eye.