Eyes: Nearsighted And Farsighted
The way our vision works is light enters the eye and it refracts on the retina. The light should refract (spread apart) evenly on the retina to allow the focus point of an object to be right by the cornea and lens of the eye. In a normal eyeball, the curvature of the cornea is the same length of the eye. However, people who have eye conditions, such as myopia or hyperopia will have trouble focusing on the objects they are looking at because of abnormal cornea curvature.
Nearsightedness is called myopia. This condition occurs when the curvature of the cornea is elongated and protrudes outward more than normal. Instead of the light refracting directly on the retina, it refracts in front of it. This causes the eyes to try and focus far away objects before the light actually reaches the retina. This is why people with myopia will see objects at far distances in a blur.
Farsightedness is called hyperopia. This condition occurs when the cornea is not curved enough, and the front of the eyeball is somewhat flatter than normal. When the light enters the eyes, it does not refract until after it passes through the retina. This causes the focus point to be behind the retina, and therefore close up objects will be blurry.
Statistics and Treatments
Nearsightedness is far more common than farsightedness. People who have either one of these conditions can also have astigmatisms as well. Presbyopia can also be mistaken for hyperopia. The most common treatments are corrective lenses, such as contacts or eyeglasses. Some people undergo eye surgeries, such as Lasik or photo-refractive keratectomy. Other alternatives are eye exercises, organized nutritional plans, or corneal rings.