Minor eye disorders are very common.Over half the Australian population uses some form of vision correction, and nearly everyone will require some vision correction at some time during their life.The most common eye problems are refractive errors such
as shortsightedness or longsightedness.
For perfectly clear vision, the image of a viewed object needs to be focused onto the retina, just as a camera has to be focused properly in order to take a clear picture. If the image is not focused exactly on
the retina, then the image will be blurred, just like an out-of-focus photograph. In this case, the person is said to have a refractive error.
Refractive errors occur when there is a mismatch between the length of the eye and its optical power. The
exact causes of refractive errors are still being studied, but it is known that both hereditary and environmental influences can affect their development. Most people have some refractive error, but in most cases the error is small, and does not cause any
problems. In fact, the average person is slightly longsighted.
Refractive errors can usually be corrected using glasses or contact lenses. There are also surgical techniques that can be used to correct refractive errors.