Error of refraction is simply defined as the blurring of one’s sight, wherein vision must be augmented by eyeglasses, contact lenses, or other treatment modalities.
A refractive error occurs when the shape of the eye prevents light from focusing directly on the retina. This can be caused by a number of things, such as the length of the eyeball being too long or too short, changes in the shape of the cornea, or a result of aging.
There are two kinds of refractive errors: Myopia and hyperopia.
Farsightedness (hyperopia) is a common vision condition in which you can see distant objects clearly, but objects nearby may be blurry. The degree of your farsightedness influences your focusing ability. People with severe farsightedness may see clearly only objects a great distance away, while those with mild farsightedness may be able to clearly see objects that are closer.
Nearsightedness (myopia) is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry. It occurs when the shape of your eye causes light rays to bend (refract) incorrectly, focusing images in front of your retina instead of on your retina. Nearsightedness may develop gradually or rapidly, often worsening during childhood and adolescence. Nearsightedness tends to run in families.
If you have been having problems, especially related to reading and straining of the eyes or experience other symptoms, such as headaches especially affecting the back of the head, with associated dizziness, nausea, and vomiting a visit to an ophthalmologist should be done.