Normal
Your eyes see an object as light coming from the object. Your cornea focuses light rays onto a layer that lines the inside of the back of your eye (the retina). If your eyes are normal, this creates a focused image on your retina. This makes objects look clear.
Nearsighted (Myopia)
Your cornea and your retina are too far apart if you’re nearsighted. In other words, your eyeball is longer than average. Sometimes your cornea or your lens has an abnormal shape. This makes light rays from distant objects focus in front of your retina. These objects then look blurry.
Farsighted (Hyperopia)
Your cornea and your retina are too close together if you’re farsighted. In other words, your eyeball is shorter than average. Sometimes your cornea or your lens has an abnormal shape. This makes light rays from close objects focus behind your retina. These objects then look blurry.
Astigmatism
Sometimes your cornea or the lens inside your eye is curved abnormally. Then light rays can’t focus evenly onto your retina. This is called astigmatism. It makes both close and distant objects look blurry.
Related Articles
Understanding Focusing Problems
Your vision depends on how light is focused in your eye. A look at 3 common problems with focusing that make vision blurry: farsightedness, nearsightedness, and astigmatism.
Flash Burn to Eye
A flash burn occurs when the eye is exposed to too much ultraviolet light, such as from welding or strong reflected sunlight.
Retinitis Pigmentosa
Retinitis pigmentosa is the name of a group of eye diseases that are passed down in families. All of them affect the retina. All of the diseases cause a slow but sure decline in eyesight.
Common Eye Disorders
One common eye disorder is conjunctivitis, sometimes called pink eye. It's an inflammation of the blood vessels in the eye membrane. Another common disorder is a chalazion—a small bump that develops on the upper or lower eyelid.
