Bethany SophMrs. CorbettAP Literature/ 7th19 April 2012 Astigmatism Forty five million Americans, one in six, all suffer from Astigmatism making itone of the most prevalent eye disorders. Astigmatism might be the most misunderstoodvision problem, defined as a visual defect in which the unequal curvature of corneaprevents light rays from focusing at one point on the retina, giving the person blurredvision (Astigmatism All About Vision). This disorder is mild however, it is excessivecausing many people to have to wear corrective lenses. Occurring in millions of people,astigmatism’s common symptoms, causes, prevalence and correction have weaved theirway into many American’s lives affecting their vision. Astigmatism’s symptoms can be confusing because of their commonality, andbecause the symptoms can increase due to a persons exhaustion level. “People withundetected astigmatism often have blurred vision which can be associated with fatigueand eyestrain” (Astigmatism WebMD). By squinting most people believe their visionproblem is temporarily solved, but this is only a temporary, tedious action. Fatigue playsa big role in detecting astigmatism because most people discover their eye disorder by thetrouble they have with their vision when they are not in focus for example, while doingtasks before they go to sleep. “Symptoms of uncorrected astigmatism are eye strain andheadaches, especially after reading or other prolonged visual tasks [usually beforesleeping]” (Astigmatism All About Vision). Headaches occur due to the lack of focus
Soph 2a person’s vision has effecting the way a person’s brain receives interprets the objectsaround him. Reading without a correcting a persons vision is not only painful but canworsen that person’s vision. Other tasks as well are equally strenuous if a person hasastigmatism, such as working on a computer for long periods of time and any tedious taskthat requires a long-term focus for person’s eyes. Astigmatism in children is moredetectable, “Parents can notice that a child may have astigmatism when the child can seesome part of a pattern or picture more clearly than others. For example, “lines goingacross 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 thecornea and how it views the images. While the picture is at different angles it can beviewed 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 thelens inside the eye” (Astigmatism American Optometric Association). Due to theirregular shape of the cornea, light is bent through the lens of a person’s eye causingblurred and distorted vision. The direct cause of astigmatism is the irregular shape of aperson’s eye. However, “Sometimes astigmatism may develop following an eye injury oreye surgery. There is also a relatively rare condition called keratoconus where the corneabecomes progressively thinner and cone shaped” (Astigmatism American OptometricAssociation). This results in an enormous amount of astigmatism consequently causingpoor vision that cannot be fully fixed with glasses. Keratoconus normally requires contactlenses for enhanced vision, and it may ultimately worsen to when a corneal transplant isnecessary. Some experts even say that astigmatism can be genetic, “To the extent that is
Soph 3true, there is nothing a person can do to avoid vision problems. However, some expertsbelieve that environmental factors may determine whether or not vision disordersdevelop. They suggest that maintaining good nutrition, reading and working in goodlight, 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 thatprotects vision, especially night vision, and once it is transferred to vitamin A in the liverit goes back to the retina. Also working in lit areas versus dark helps keep your eyes infocus causing less strain, and same goes for wearing proper corrective lenses. Astigmatism’s prevalence has been growing amongst many Americans, “In arecent 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 significantdifferences in astigmatism prevalence based on ethnicity. Asian and Hispanic childrenhad 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 ahigher 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 thirtyyears ago; most professionals believe this low number though came from lack ofawareness and attention. “In another large study of more than 11,000 eyeglass wearersconducted recently in the UK, 47.4 percent of wearers had astigmatism of 0.75 D orgreater 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
Soph 4hyperopic astigmatism (15.7 percent)” (Astigmatism All About Vision). This studyproves close to half of the people in the study had astigmatism in one eye and a fourth ofthe same people had the vision disorder in both. Myopic astigmatism simply means oneor both principal medians are nearsighted, and hyperopic astigmatism is when one or bothprincipal medians are farsighted. “According to statistics from the American Academy ofOphthalmology, about one in every three people are affected by astigmatism.. Often,nearsightedness or farsightednesses occur along with astigmatism. Many people whohave astigmatism are born with it, while others may develop astigmatism after an eyeinjury or disease.” (Astigmatism Statistics About Astigmatism). With the growing rate ofastigmatism many specialists are beginning to conclude it has become a genetic disorder,inheriting the curvature of the cornea from former generations. The link betweenfarsightedness and nearsightedness to astigmatism, however, is still unknown. With the vision disorder progression in our upcoming generations, correctionhowever, is easily attainable “Almost all degrees of astigmatism can be corrected withproperly prescribed eyeglasses or contact lenses. For a person with only a slight degree ofastigmatism, corrective lenses may not be needed at all, as long as other conditions suchas nearsightedness or farsightedness are not present” (Astigmatism WebMD). Theprescription of a person’s eyewear correlates directly to the amount of astigmatismpresent in their vision disorder. While contact lenses are generally preferred, in somecases, usually in children, they are not attainable due to the seriousness of theastigmatism. “Astigmatism can also be corrected by reshaping the cornea using a highlyfocused laser beam of light. Two commonly used procedures are photorefractive
Soph 5keratectomy (PRK) and laser in situ keratomileusis (LASIK)” (Astigmatism AmericanOptometric Association). LASIK eye surgery is the one most commonly used by doctorsand this surgery also gives patients better outcomes. However, children cannot partake inthis procedure, for it is only for adults whose eyes have stopped developing. “Gaspermeable contact lenses also correct astigmatism. Because these lenses are rigid andoptically replace the cornea as the refracting surface of the eye, a cylinder power and axismay or may not be needed, depending on the type and severity of astigmatism correctionrequired” (Astigmatism All About Vision). Gas permeable lenses also cannot be used forpatients who have irritable eyes, due to the amount of discomfort brought on by theplastic-like middle of the contact. These contacts, however, are more accurate and preciseand make it perfect vision easier attainable. Astigmatism is one of the most prevalent eye disorders, taking place in one andsix 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, prevalenceand correction have weaved their way into many American genetics affecting theirvision. As the disease progresses into the future, its understandings and treatments canonly progress as well.
Works CitedAngela, 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.