What is astigmatism?
Astigmatism is a common eye
condition marked by an irregular curvature of the cornea. This type
of disorder is also known as a refractive error, and occurs in
nearly everyone to some degree. If the cornea is significantly
curved, the condition must be treated.
A person's eye is naturally spherical in shape. Under
normal circumstances, when light enters the eye, it refracts
evenly, creating a clear view of the object. However, the eye of a
person with astigmatism is shaped more like a football or the back
of a spoon. For this person, when light enters the eye, it is
refracted more in one direction than the other, allowing only part
of the object to be in focus at one time. Objects at any distance
can appear blurry and wavy.
What causes astigmatism?
Astigmatism can be
hereditary and is often present at birth. It can also be the result
of pressure from the eyelids on the cornea, incorrect posture, or
an increased use of the eyes for close work.
What are the symptoms of astigmatism?
People with
undetected astigmatism often experience headaches, fatigue,
eyestrain and blurred vision at all distances. While these symptoms
may not necessarily be the result of astigmatism, you should
schedule an eye exam if you are experiencing one or more
symptoms.
How is astigmatism diagnosed?
Astigmatism can only
be diagnosed with a thorough eye exam by your optometrist or
ophthalmologist. Astigmatism may occur with other refractive errors
such as myopia (nearsightedness) and hyperopia
(farsightedness). Unfortunately, astigmatism often goes
undetected in school-age children.
Because astigmatisms may increase slowly, you should visit your
optometrist or ophthalmologist for an eye exam once a year.
Optometrists are trained specifically to determine and improve
visual acuity with the prescription of eyeglasses or contact
lenses. Ophthalmologists can provide total eye care, from
examinations and vision correction to the diagnosis and treatment
of disease through medication and surgery.
How is astigmatism treated?
Almost all degrees of
astigmatism can be corrected with properly prescribed glasses or
lenses. For a person with only a slight degree of astigmatism,
corrective lenses may not be needed at all, as long as other
conditions such as nearsightedness or farsightedness are not
present. If the astigmatism is moderate to high, however,
corrective lenses are probably needed.
For astigmatism, special corrective lenses called toric lenses
are prescribed. Toric lenses have greater light bending power in
one direction than the other. After performing various tests, your
eye doctor will determine the ideal toric lens prescription for
your astigmatism.
Another method for correcting astigmatism is by changing the
shape of the cornea through refractive surgery. While there is more
than one type of refractive surgery, specific treatments are
recommended on an individual basis.
Refractive surgeries require healthy eyes that are free from
retinal problems, corneal scars, and any eye disease. As technology
progresses, it is important that you explore all options and
possibilities before deciding which refractive surgery and
treatment is right for you.