Myopia is also called nearsightedness, it is a refractive disorder where distant object cannot be seen clearly. This condition occurs because light rays coming to an eye from distant object focus in front of retina and the resulting image on the retina is
blurry. The most common reason for myopia is elongation of an eyeball and normal refractive power becomes too strong for an eye. The images formed on the retina are blurry and therefore cannot be seen clearly. This form of myopia is known as axial myopia. In some rare cases it is possible that refractive power of an eye is too strong for a normal size of an eyeball and images from distant objects again focus in front of retina instead on it. The reason is either a strong refractive power of cornea (for example in condition known as keratoconus), or lens (for example condition known as lenticonus. Source:http://www.refractiveeyedisorders.com/myopia-nearsightedness/
