Myopia (Nearsightedness)
This is a condition in which light comes to a focus in front of the retina when the eye is relaxed creating blurry distance vision. It occurs for several reasons from the cornea being too round or the eye being too long. It tends to be progressive as the eye continues to grow or elongate usually into your late teens or twenties. Correction of myopia involves glasses, contact lenses, or laser surgery.
Hyperopia (Farsightedness)
This is a condition in which light comes to a focus behind the retina when the eye is relaxed creating blurry vision especially up close. It occurs for several reasons from the cornea being too flat or the eye being to short. It tends to be more common in children and may improve as the eye continues to grow or elongate usually into your late teens or twenties. Uncorrected hyperopia may be responsible for eyeturns or lazy eyes. Correction of hyperopia involves glasses, contact lenses, or laser surgery.
Astigmatism
This condition is caused by the cornea (front of the eye) being football or egg shaped instead of round. This causes the image to appear smeared, stretched, or doubled for both distance and near images. This condition is also correctable with glasses , contact lenses, or laser surgery.
Presbyopia
This condition is caused by reduced flexibility of the crystaline lens within the eye when viewing close images. It occurs usually around forty years of age with changes into your fifties. It is correctable with contact lenses and glasses. There are some surgical treatments being offered but they are still new. More options are being developed and improved at this time with laser, radiowaves, or implantable lenses.