Nearsightedness, or myopia, is a condition in which light does not hit the retina correctly due to the eyes being longer than normal or the corneas being too curved, making far away objects appear blurred, notes Everyday Health. People who suffer from farsightedness, or hyperopia, have difficulty focusing on close objects because their eyes are too short, or their corneas do not have enough curve, to read closer light waves correctly.
Nearsighted individuals have trouble focusing on distant objects such as movie screens, and children may have difficulty in school because of their inability to focus on objects such as blackboards, explains Everyday Health. Farsighted people may suffer from headaches and fatigue after trying to focus on near objects, and they have difficulty concentrating.
Doctors test people for nearsightedness and farsightedness using eye charts with lines that are both close and farther off, notes Everyday Health. While patients read the charts, doctors use phoropters with various lenses to measure errors in the way light rays enter the eyes. They also shine lights in patients' eyes to view how light reflects off the back of the retina. People may choose to wear eyeglasses or contact lenses to correct nearsightedness or farsightedness, and the lenses change the way light hits the retina. Contacts may be more effective, as they sit right on the eye and can refocus light.