|
What is Hypermetropia?
If you can see objects at a distance clearly but have trouble
focusing well on objects close up, you may be farsighted.
Your eye care practitioner
may refer to farsightedness as long-sightedness, or by its medical
names, hypermetropia or hyperopia. Hypermetropia causes the eyes
to exert extra effort to see close up. After viewing nearby objects
for an extended period, you may experience blurred vision, headaches
and eyestrain. Children who are farsighted may find reading difficult.
Hypermetropia is not a
disease, nor does it mean that you have "bad eyes."
It simply means that you have a variation in the shape of your
eyeball. The degree of variation will determine whether you will
need corrective lenses.
What causes hypermetropia?
Hypermetropia most commonly occurs because the eyeball is too
short; that is, shorter from front to back than is normal. In
some cases, the cornea having too little curvature may cause
hypermetropia.
Normal Eye
|
Hypermetropic Eye
|
Exactly why eyeball shape
varies is not known, but the tendency for farsightedness is inherited.
Other factors may be involved too, but to a lesser degree than
heredity.
How does hypermetropia
affect sight?
Our ability to "see" starts when light enters the eye
through the cornea. The shape of the cornea and the lens help
bend (refract) light rays in such a manner that light is focused
into a point precisely on the retina.
If, as in farsightedness,
the eyeball is too short, the "point of light" focuses
on a location behind the retina, instead of on the correct area
of the retina, known as the fovea. Consequently, at the point
on the retina where a fine point of light should be focused,
there is instead a disk-shaped area of light. Since light is
not focused when it hits the retina, vision is blurred.
Convex lenses are prescribed
to bend light rays more sharply and bring them to focus on the
retina.
Who is affected by hypermetropia?
Many people have a degree of farsightedness, yet it is only a
problem if it significantly affects our ability to see well or
causes headaches or eyestrain.
How is it diagnosed?
Hypermetropia is seldom diagnosed in school eye-screening tests,
which typically test only the ability to see objects at a distance.
A comprehensive eye health examination that checks both near
and far vision is necessary to diagnose farsightedness.
How is it treated?
Convex lenses, eyeglasses or contact lenses are usually prescribed.
They bend light more sharply and bring them to focus on the retina.
If you do not have other vision problems such as astigmatism,
you may only need glasses for reading or other tasks done at
a close range.
To determine the best avenue
of treatment, your eye care professional may ask a number of
questions about your lifestyle, occupation, daily activities
and general health status. For instance, you may be asked whether
you frequently need near vision. Providing candid, considered
answers to the questions and working with your eye care professional
will help assure that your corrective lenses contribute to clear
sight and general comfort.
A comprehensive eye examination
at the recommended intervals will ensure that minor changes in
vision are diagnosed and treated so that your vision will remain
as clear and comfortable as possible.
How will hypermetropia
affect your lifestyle?
If glasses or contact lenses are prescribed, it may take a few
days to adjust to them. After that, farsightedness probably will
not significantly affect your lifestyle. |