MODEL RELEASED. Lazy-eye treatment. 3-year-old girl wearing an eye patch over her left eye to treat a lazy-eye (amblyopia). Amblyopia is a permanent defect of visual sharpness where there is no structural abnormality in the eye. It is usually caused by a disturbance of the visual pathway between the eye and the brain. It can be caused by a squint, where only one eye points directly at a specific image. In such a case, vision in the other eye will be suppressed by the brain. Treatment involves forcing the bad eye to function properly by covering the good eye.