How the eyes work
In an eye with perfect vision, light rays pass through the cornea and the lens (at the front of the eye) and are focused directly on the retina at the back of the eye to produce a clear image.
Eyes vary in size and proportion from person to person, just like other parts of the body. A perfect eye has an evenly-rounded cornea that focuses light right on the retina, resulting in perfect vision. If the cornea is too flat or the eye is shaped a little differently, the natural focal point may be a little in front of, or a little behind the retina. This is known as a refractive error, and the result is a blurred image.
There are three common conditions that account for 95% of refractive errors; short-sight, long-sight and astigmatism.
Image focuses in front of the retina. Close objects can generally be seen clearly, but more distant objects are blurred.
Image would naturally focus behind the retina. Distant objects can generally be seen clearly, but closer objects appear blurred.
Usually due to the cornea being more steeply curved in one direction than the other.
Objects appear stretched or elongated in the direction of the astigmatism
There are a number of different types of eye surgery to correct myopia, hyperopia and astigmatism. Your eye surgeon will be able to recommend the options that are most suitable for you, based on the type of refractive error, the overall health of your eyes, your lifestyle and your general health.