For our eyes to be able to see, the light rays entering them must be focused by the lens onto the light-sensitive retina at the back of the eye. If the light is not focused properly, the image will appear blurry to us. The cause of the blurred vision is not a defect in the lens, but rather a change in the length of the eye. In cases of myopia, the eye is longer than normal. Thus, the image focuses on a point in front of the retina.
Close objects appear clear while far away objects are fuzzy.
Hyperopic eyes are shorter that normal, causing the image to land on the retina before it is completely focused. Persons suffering from myopia have trouble seeing close objects, while their distance sight remains unaffected. Both myopia and hyperopia tend to be inherited. Inherited myopia is most often detected between eight and twelve years of age. It tends to worsen during adolescence and remain stable in the years leading up to middle age.