1. Bethany Soph
Mrs. Corbett
AP Literature/ 7th
19 April 2012
Astigmatism
Forty five million Americans, one in six, all suffer from Astigmatism making it
one of the most prevalent eye disorders. Astigmatism might be the most misunderstood
vision problem, defined as a visual defect in which the unequal curvature of cornea
prevents light rays from focusing at one point on the retina, giving the person blurred
vision (Astigmatism All About Vision). This disorder is mild however, it is excessive
causing many people to have to wear corrective lenses. Occurring in millions of people,
astigmatism’s common symptoms, causes, prevalence and correction have weaved their
way into many American’s lives affecting their vision.
Astigmatism’s symptoms can be confusing because of their commonality, and
because the symptoms can increase due to a persons exhaustion level. “People with
undetected astigmatism often have blurred vision which can be associated with fatigue
and eyestrain” (Astigmatism WebMD). By squinting most people believe their vision
problem is temporarily solved, but this is only a temporary, tedious action. Fatigue plays
a big role in detecting astigmatism because most people discover their eye disorder by the
trouble they have with their vision when they are not in focus for example, while doing
tasks before they go to sleep. “Symptoms of uncorrected astigmatism are eye strain and
headaches, especially after reading or other prolonged visual tasks [usually before
sleeping]” (Astigmatism All About Vision). Headaches occur due to the lack of focus

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a person’s vision has effecting the way a person’s brain receives interprets the objects
around him. Reading without a correcting a persons vision is not only painful but can
worsen that person’s vision. Other tasks as well are equally strenuous if a person has
astigmatism, such as working on a computer for long periods of time and any tedious task
that requires a long-term focus for person’s eyes. Astigmatism in children is more
detectable, “Parents can notice that a child may have astigmatism when the child can see
some part of a pattern or picture more clearly than others. For example, “lines going
across may seem clearer than lines going and down,” says Dr. John Lohr (Astimgatism).
The reason for the some of the lines being blurry has to do with the curvature of the
cornea and how it views the images. While the picture is at different angles it can be
viewed differently by the child having blurred in areas the cornea’s straining to see.
By definition, “Astigmatism occurs due to the irregular shape of the cornea or the
lens inside the eye” (Astigmatism American Optometric Association). Due to the
irregular shape of the cornea, light is bent through the lens of a person’s eye causing
blurred and distorted vision. The direct cause of astigmatism is the irregular shape of a
person’s eye. However, “Sometimes astigmatism may develop following an eye injury or
eye surgery. There is also a relatively rare condition called keratoconus where the cornea
becomes progressively thinner and cone shaped” (Astigmatism American Optometric
Association). This results in an enormous amount of astigmatism consequently causing
poor vision that cannot be fully fixed with glasses. Keratoconus normally requires contact
lenses for enhanced vision, and it may ultimately worsen to when a corneal transplant is
necessary. Some experts even say that astigmatism can be genetic, “To the extent that is

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true, there is nothing a person can do to avoid vision problems. However, some experts
believe that environmental factors may determine whether or not vision disorders
develop. They suggest that maintaining good nutrition, reading and working in good
light, and wearing corrective lenses as prescribed can reduce the risk of eye problems”
(Newton). They myth that eating carrots is actually true, they contain Beta-Carotene that
protects vision, especially night vision, and once it is transferred to vitamin A in the liver
it goes back to the retina. Also working in lit areas versus dark helps keep your eyes in
focus causing less strain, and same goes for wearing proper corrective lenses.
Astigmatism’s prevalence has been growing amongst many Americans, “In a
recent study of 2,523 American children ages five to seventeen years, more than twenty-
eight percent had astigmatism of one diopter (D) or greater. Also, there were significant
differences in astigmatism prevalence based on ethnicity. Asian and Hispanic children
had the highest prevalence (33.6 and 36.9 percent, respectively), followed by whites
(26.4 percent) and African-Americans (20.0 percent)” (Astigmatism All About Vision).
The different percentages for each ethnic group is not relevant and no ethnicity has a
higher chance of having this vision disorder than another it just happened in this study.
However, the prevalence in children is growing only being one in fourteen less than thirty
years ago; most professionals believe this low number though came from lack of
awareness and attention. “In another large study of more than 11,000 eyeglass wearers
conducted recently in the UK, 47.4 percent of wearers had astigmatism of 0.75 D or
greater in at least one eye, and 24.1 percent had this amount of astigmatism in both eyes.
The prevalence of myopic astigmatism (31.7 percent) was approximately double that of

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hyperopic astigmatism (15.7 percent)” (Astigmatism All About Vision). This study
proves close to half of the people in the study had astigmatism in one eye and a fourth of
the same people had the vision disorder in both. Myopic astigmatism simply means one
or both principal medians are nearsighted, and hyperopic astigmatism is when one or both
principal medians are farsighted. “According to statistics from the American Academy of
Ophthalmology, about one in every three people are affected by astigmatism.. Often,
nearsightedness or farsightednesses occur along with astigmatism. Many people who
have astigmatism are born with it, while others may develop astigmatism after an eye
injury or disease.” (Astigmatism Statistics About Astigmatism). With the growing rate of
astigmatism many specialists are beginning to conclude it has become a genetic disorder,
inheriting the curvature of the cornea from former generations. The link between
farsightedness and nearsightedness to astigmatism, however, is still unknown.
With the vision disorder progression in our upcoming generations, correction
however, is easily attainable “Almost all degrees of astigmatism can be corrected with
properly prescribed eyeglasses or contact 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” (Astigmatism WebMD). The
prescription of a person’s eyewear correlates directly to the amount of astigmatism
present in their vision disorder. While contact lenses are generally preferred, in some
cases, usually in children, they are not attainable due to the seriousness of the
astigmatism. “Astigmatism can also be corrected by reshaping the cornea using a highly
focused laser beam of light. Two commonly used procedures are photorefractive

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keratectomy (PRK) and laser in situ keratomileusis (LASIK)” (Astigmatism American
Optometric Association). LASIK eye surgery is the one most commonly used by doctors
and this surgery also gives patients better outcomes. However, children cannot partake in
this procedure, for it is only for adults whose eyes have stopped developing. “Gas
permeable contact lenses also correct astigmatism. Because these lenses are rigid and
optically replace the cornea as the refracting surface of the eye, a cylinder power and axis
may or may not be needed, depending on the type and severity of astigmatism correction
required” (Astigmatism All About Vision). Gas permeable lenses also cannot be used for
patients who have irritable eyes, due to the amount of discomfort brought on by the
plastic-like middle of the contact. These contacts, however, are more accurate and precise
and make it perfect vision easier attainable.
Astigmatism is one of the most prevalent eye disorders, taking place in one and
six Americans. While its prevalence is still a mystery, the vision disorder itself is not,
being one of the most understood eye disorders in ophthalmology and optometry.
Occurring in millions of people, astigmatism’s common symptoms, causes, prevalence
and correction have weaved their way into many American genetics affecting their
vision. As the disease progresses into the future, its understandings and treatments can
only progress as well.

6. Works Cited
Angela, Woodward. “Behavioral Optometry .” The Gale Encyclopedia of Alternative
Medicine. Gale Virtual Reference Library. Web. 14 Oct. 2011.
Answers.com. N.p., n.d. Web. 13 Nov. 2011.
“Astigmatism.” All About Vision. N.p., n.d. Web. 13 Nov. 2011.
“Astigmatism.” American Optometric Association. N.p., n.d. Web. 13 Nov. 2011.
“Astigmatism.” MayoClinic. N.p., n.d. Web. 13 Nov. 2011.
“Astigmatism.” PubMed Health. N.p., n.d. Web. 13 Nov. 2011.
“Astigmatism.” WebMD. N.p., n.d. Web. 13 Nov. 2011.
Lohr, John. “Astigmatism .” The Gale Encyclopedia of Medicine. N.p., n.d. Web. 17 Oct.
2011.
Newton, David, and Donna Olendorf. “Vision Disorders.” Gale. Gale Virtual Reference
Library. Web. 13 Nov. 2011.
“Statistics about Astigmatism .” RightDiagnosis. N.p., n.d. Web. 13 Nov. 2011.