If your eye is out of focus it could be due to refractive error. This occurs when light rays do not properly focus on the retina.
Short sight (Myopia) If you are short sighted or myopic your eye is longer or stronger in power than normal. This causes light rays to be focused in front of the retina. The result is that your eye is focused for close range vision and blurry for distance vision.
Most short sighted people wear glasses or contact lenses most of the time depending on the degree of myopia and their visual requirements. However, short sighted people may prefer to take their glasses off to read.
Long sight (Hypermetropic) If you are long sighted or hypermetropic your eye is shorter or less powerful than normal. This causes light rays to come to a focal point behind the retina.
Some Long sighted people do not start wearing glasses until they are older, as they can use additional focusing power to clear the vision when they are young.
Long sighted people normally end up wearing glasses or contact lenses most of the time as their vision is blurred for both near and distant objects.
Astigmatism If you have Astigmatism your cornea is oval in shape rather than spherical causing visual distortion. This can occur in combination with long or short sightedness.
Presbyopia As you age the crystalline lens within the eye becomes increasingly rigid causing loss of focus at near range. Presbyopia occurs in all people regardless of refractive error.
Treatment for Refractive Errors
Treatment for Refractive Errors can include correction with prescription glasses, contact lenses or with refractive surgery, such as LASIK or PRK.