Common Refractive Problems

Myopia is the medical term for "nearsightedness," a condition in which the eyes can see close objects but not distant objects.  Myopia is usually an inherited trait and is oftentimes found in children between the ages of 8 and 12. Myopia increases as children grow, leveling off in adulthood.  Myopia less commonly manifests itself in adulthood.  It is a misconception that excessive reading, computer use, and diet have an effect on the presence and/or progression of myopia.  A myopic eye is not as round as a normal eye, tending to be a more elongated oval shape.  This oval shape causes light to be focused slightly in front of the retina, resulting in the perception of a blurred image.  Myopia is easily correctable with glasses or contact lenses.  In some cases laser vision correction may be an option.

Hyperopia

Hyperopia is the opposite condition to myopia.  Instead of an ability to see near objects better than far, the hyperopic eye sees far objects better than near.  The hyperopic eye is a shortened oval, as compared to a normal eye.  This shortness causes light to focus behind the retina, causing the perception of a blurred image.  Hyperopia is easily correctable with glasses or contact lenses and laser vision correction is now available for up to 6 diopters of correction with minimal accompanying astigmatism.

Astigmatism

Astigmatism is a distortion of light as it passes through the cornea.  The astigmatic eye has a cornea which is not perfectly smooth and spherical, with equal curvature on all sides.  Because the astigmatic eye is not round, but shaped more like a football, there is a distortion or tilting of images due to asymmetric bending of light rays.  Astigmatism is correctable with corrective lenses and, in some cases, laser vision correction may be an option.

Presbyopia

Presbyopia is an age-related disorder caused by a loss of focusing power in the eyes.  As a result of this condition, nearsighted people may need to add bifocals to their corrective lenses, and some people who have never had to wear glasses before may need to start wearing reading glasses.  Some people with mild nearsightedness may only need to remove their corrective lenses to read or do close work.