Myopia, commonly known as nearsightedness, is a vision condition where people can see close objects clearly, but distant objects appear blurry. This happens because light from distant objects focuses in front of the retina instead of directly on it. The eye shown here demonstrates how light rays from a distant tree converge before reaching the retina, creating a blurry image.
Let's compare normal vision with myopic vision. In a normal eye, light rays from distant objects focus precisely on the retina, creating a clear image. However, in a myopic eye, the eyeball is typically longer than normal, causing light rays to converge before reaching the retina. This results in the focal point being in front of the retina, making distant objects appear blurry.
There are several physical causes of myopia. The most common cause is an eyeball that is too long from front to back, called axial myopia. This extra length means light focuses before reaching the retina. Another cause is a cornea that is too curved, which bends light rays too much. A lens that is too thick or curved can also cause the same focusing problem. All these conditions result in light converging in front of the retina instead of directly on it.
Myopia can be effectively corrected using several methods. The most common correction uses concave or diverging lenses, which spread out light rays before they enter the eye. This allows the light to focus properly on the retina instead of in front of it. Contact lenses work similarly, and refractive surgery like LASIK reshapes the cornea to achieve the same effect. All these methods move the focal point back to where it should be - directly on the retina.
To summarize, myopia or nearsightedness is a common vision condition where distant objects appear blurry because light focuses in front of the retina instead of on it. This is typically caused by an eyeball that is too long or a cornea that is too curved. Fortunately, myopia can be easily corrected using concave lenses, contact lenses, or refractive surgery, all of which help move the focal point back onto the retina for clear distance vision.