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| A farsighted eye is too “short,” causing
light to converge behind the retina and blurring
near vision. |
Overview
Farsightedness, medically known as hyperopia (hi-pur-OH-pea-uh),
refers to vision that is good at a distance but may be
poor at close range. Farsightedness occurs when the
eyeball is shorter than normal, as measured from front
to back, or when the cornea has too little curvature.
This reduces the distance between the cornea and retina,
causing light to converge behind the retina, rather than
on it.
Since we’re usually born with eyes that are too
short, the majority of newborns are farsighted. As we
grow, the “normal” eye gets longer and by 1 year, close
vision is generally clear. Even when it doesn’t,
farsightedness – also known as hypermetropia and
long-sightedness – may go unnoticed until middle age –
when the ciliary muscles controlling the lens begin to
weaken and can no longer compensate for the limitation
in near vision. This is why farsightedness, which is
usually congenital, often isn’t apparent until the
development of presbyopia.
Disease such as retinopathy, eye tumors and lens
dislocation can also contribute to farsightedness, which
is easily treated with corrective lenses and can also be
managed with refractive laser surgery.
Symptoms
People who are farsighted typically have good distance
vision, but may find it difficult to do close visual
tasks, such as reading. Besides blurred vision or
difficulty focusing during close activities such as
reading or sewing, other symptoms include:
- Aching, burning, red or tearing eyes
- Eye fatigue
- Headaches or “brow” aches (occurring on the top
of the eye), which can result from overworked
ciliary muscles
- Poor hand-eye coordination
- Severely farsighted children may appear
cross-eyed – a condition called accommodative
esotropia that usually develops around age 3 and may
be constant or intermittent.
Prevention
Farsightedness is largely believed to be inherited, with
little evidence that enviromental factors cause its
development. However, to avoid accentuating symptoms,
your eyecare practitioner may recommend that you keep
work areas well-lit and glare-free and give your eyes a
break during close visual work by focusing on distant
objects every 30 minutes or so.
Occasionally, conditions such as diabetes, lens
dislocations and eye tumors can cause farsightedness. So
if you experience any symptoms, see your eye doctor for
a complete examination. Children should get a complete
eye exam by age 3 and those with severe hyperopia need
to be monitored to avoid the development of crossed eyes
(strabismus) or lazy eye (amblyopia).
Treatment
If you are mildly farsighted, your eyecare practitioner
may not recommend corrective treatment at all, since
your ciliary muscles may be compensating by adjusting
the shape of your lens to bring close vision into focus.
However, if you are moderately or severely hyperopic or
presbyopic, you have several treatment options:
- Corrective Lenses
- Eyeglasses with convex lenses, which
are thicker in the center and thinner on the
edges, to bend light to converge further forward
in the eye to reach the retina.
- Contact lenses offer several options,
such as soft lenses and rigid gas-permeable
(RGP) lenses, which conform to the shape of the
lens
- Laser surgery is effective for many
people with farsightedness, but the long-term
effects of these relatively new procedures are still
being studied. Laser surgery, which still may result
in the need for reading glasses, is generally not
recommended for those under age 18 and carries risk
of side effects such as increased sensitivity to
glare, seeing halos around lights, poor vision, dry
eye and others. Options include:
- LASIK (laser in situ keratomileusis)
is a procedure in which a surgeon slices a flap
into the cornea and a laser removes some tissue
from beneath the sliced area to reshape the
cornea.
- Photorefractive keratotomy (PRK) uses
a laser beam to remove tissue from the outer
surface of the cornea, reshaping it to improve
its focus.
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