Myopia (also called short-sightedness) is a condition in which the eyeball itself is either too long, or the front of the eye (the cornea) is too curved, or a combination of both. The result is that light from distant objects is focused in front of the retina (instead of on the retina). This makes doing things like driving and readingfar-off signs difficult. Myopia can be corrected with either soft contact lenses or RGP (gas permeable) contact lenses.
Hyperopia (also called hypermetropia or long-sightedness) is a condition in which the eyeball is too short, or the cornea is too curved, or a combination of both. The result is that light from objects is focused behind the retina. We can use some of the focusing power of the natural lenswithin the eye to help refocus the light, but this can lead to "eyestrain" or tired eyes, especially when working at near. The focusing ability of the eyes also reduces as we get older, making it more difficultto overcome thefocusing problem. Hyperopia can be corrected with either soft contact lenses or RGP (gas permeable) contact lenses.
Astigmatism is a condition in which the front of the eye (the cornea) is oval shaped instead of round. Some people describe it as having rugby ball shaped cornea instead of a soccer ball shaped cornea. There are two types of astigmatism, regular and irregular. Regular astigmatism is able to be corrected with glasses, soft (toric) or RGP (gas permeable) contact lenses.Irregular astigmatism is usually not well corrected with spectacles or softcontact lenses,unless it is fairly mild.