2. The human eye gathers light from objects. In a healthy eye, a smaller, inverted, real image of an object is created on the retina at the back of the eye. Electrical impulses from the eye travel through the optic nerve to the brain. The brain allows us to interpret the light signals on the retina as an image of the object. THE HUMAN EYE: How Images Are Formed 13.6

3. Eye muscles called ciliary muscles slightly change the shape of the eye lens. The process of accommodation makes it possible to create a sharply focused image on the retina if an object is distant or nearby.accommodation

4. Sometimes the human eye is not able to focus on objects and create a sharply focused image. There are three common focusing problems: –hyperopia (far-sightedness)hyperopia – presbyopia (age-related far-sightedness)presbyopia – myopia (near-sightedness)myopia THE HUMAN EYE: Focusing Problems 13.6

5. Myopia – focus in front of retina Hyperopia – focus behind retina Normal Vision – focus at retina