Nearsightedness, or myopia, is the most common refractive condition
and affects one in four people. Nearsightedness is a condition in
which light rays entering the eye focus in front of the retina instead
of directly on the retina. Nearsightedness is normally caused when
the eye is too long or the cornea is too steep. Nearsighted patients
see nearby objects clearly, but have difficulty focusing on distant
objects. Myopia can be minimal, creating only slight blurring of distant
vision. Those with minimal myopia may be able to read the doctor's
eye chart without glasses. Those with moderate myopia are barely
able to see the big E on the eye chart without glasses or contacts.
Nearsightedness is often inherited, usually starts in childhood
and stabilizes in the late teens or early adulthood.
Farsightedness is a condition where light rays entering the eye
focus behind the retina, resulting in blurry vision. In a hyperopic
eye, the light rays do not converge or focus by the time they reach
the retina. Hyperopia results from having an eye that is shorter
than normal or a cornea that is flatter than normal. In this condition
far vision is better than near vision. If the amount of farsightedness
is large enough, and depending on the age of the patient, it will
also blur distant objects, however the near vision will still be
If your vision is blurred at all distances, you may have astigmatism.
This condition is the result of having a corneal surface that is
irregular in shape, somewhat like a football instead of a more rounded
basketball. With astigmatism, the rays of light do not converge
into a single point but form two or more focal points. Thus the
eye is unable to focus clearly at any distance because of this irregular
focusing surface. This causes people to experience blurry or distorted
During childhood, our eyes have the ability to focus on
objects as close as our nose to objects very far away. The lens
in our eyes acts similar to focusing lens in a camera. As each year
passes, that ability to "focus" decreases. Typically,
by the time we reach our forties, we will need an aid, such as reading
glasses or bifocals, to focus on objects near to us. This condition
is called presbyopia.
When a nearsighted (Myopic) person is wearing glasses or contact
lenses to correct their vision, they too experience presbyopia.
Because the nearsighted eye has a natural focal point "at near",
many nearsighted presbyopes can remove their glasses or contact
lenses and read or do close work comfortably. Many myopes choose
to wear bifocals to eliminate the need for removing and replacing
their glasses. If you plan to have refractive surgery to eliminate
or reduce your myopia, like everyone else, you will still experience
presbyopia sometime in your forties. Likewise, farsighted patients
will also experience presbyopia and need reading glasses whether
or not they have had LASIK.
Many presbyopic contact lens wearers choose to wear a contact
lens on one eye that does not fully correct the myopia, enabling
that eye to focus on objects at near, while the other eye focuses
well on distant objects. This type of correction is called monovision. There are various types of astigmatism including regular, mixed,
asymmetric and irregular astigmatism. Corneal topography will define
astigmatism in the greatest detail. Patients who have astigmatism
should feel comfortable that it is routinely corrected with their
nearsightedness or farsightedness at the time of surgery.
If you have any questions or would like to schedule a free consultation
with Ohio Valley Eye Institute please call us at (812) 421-2020
or contact us online.