Understanding Vision Problems
Changes in the shape and size of your eyes can cause
problems that affect the way you see things that are
close up or far away. These problems are referred to
as refractive disorders. Refractive disorders include
myopia (nearsightedness), hyperopia (farsightedness),
presbyopia, and astigmatism. This section will help
you to understand these disorders and what they might
mean to you.
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What is Presbyopia?
 People often confuse farsightedness with this
condition, which occurs as the normal result of
aging. Presbyopia affects most people by the age
of 40 and everyone by the age of 51. This is
because the aging process diminishes our natural
ability to bring near objects into focus. This
condition manifests when the lens inside the eye
loses its flexibility, preventing accurate focus
on objects in the near field of view, such as
reading material.
Presbyopia can affect people who are myopic,
emmetropic (no refractive error) and hyperopic.
The latter combination is especially problematic
because hyperopes often lose both distance and
near vision at the same time after 40 years of
going without glasses or contacts.
Symptoms and options
With presbyopia, you may experience eye fatigue
when reading in poor light or at the end of the
day, trouble changing focus from distance to
near or the need to constantly reposition
reading material to find the right focus. This
condition is traditionally corrected with
reading glasses, bifocals or contact lenses.
NearVision CK
(Conductive Keratoplasty)
employs the only technology developed and
approved specifically for this condition.
What is Hyperopia?
Hyperopia or farsightedness is a very common
refractive disorder, affecting up to 62% of people
over the age of 40. With hyperopia, you may see
objects that are far away, but have difficulty
focusing on near objects. You may also find that you
can see things clearly, but have to strain your eyes
to maintain focus.
Hyperopia occurs when the eyeball is too short or
the cornea is too flat. When light enters a
hyperopic (short) eyeball, it is focused behind the
retina instead of directly on the retina where light
must be directed for normal vision. Because of this,
the focusing apparatus of the eye must constantly
work to compensate and focus images.
Symptoms and options
Symptoms of hyperopia include blurred vision,
eyestrain or headaches (especially when reading or
at the end of the day). They will increase over
time. Doctors prescribe a "plus" or convex
corrective lens, in the form of eyeglasses or
contacts, for the disorder. Hyperopia can also be
corrected by steepening the central cornea using a
vision procedure such as laser surgery or
NearVision
CK
(Conductive Keratoplasty).
What is Myopia?
Myopia affects 26% of the non-Asian population.
(Note: Myopia occurs at a much higher rate in the
Asian population.) It is a condition in which you
have difficulties seeing objects in the distance,
but may not have problems focusing on objects close
up. When the eyeball is too long or the cornea too
steep, myopia is the result. Light enters a myopic
(long) eyeball and is focused on the front of the
retina, instead of directly on the retina for normal
vision.
Symptoms and correction
Symptoms of myopia include eyestrain, blurred vision
or headaches. Doctors prescribe "negative" or
concave corrective lenses (eyeglasses or contact
lenses) for this condition. Laser vision procedures
can also surgically treat myopia.
What is Astigmatism?
In an eye with astigmatism, the front of the cornea
is not equally curved; it is slightly oval in shape,
much like a football, and causes light entering the
eye to bend unequally, therefore distorting the
image. This condition affects nearly 30% of the
non-Asian population. Often, astigmatism occurs in
conjunction with myopia or hyperopia, which can
complicate refractive surgery.
Symptoms and correction
Astigmatic symptoms alone can be difficult to
detect, but it's possible that you may notice a
subtle difficulty focusing on objects such as
printed words. Your doctor, however, can
definitively identify this condition during a
comprehensive eye examination. Eyeglasses, contact
lenses and even refractive surgery can effectively
correct astigmatism.
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