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Christina TaHSC 400Descriptive epidemiology of GlaucomaCalifornia State University, Long BeachNovember 1, 2017Extent of the ProblemGlaucoma is considered a group of eye disorders that can lead to optic nerve damage; this would then ultimately result in vision loss or even blindness (American Optometric Association, n.d.). It is a serious condition as it is the second-leading cause of blindness in the United States (American Optometric Association, n.d.). The fact that this condition is one of the top two reasons for Americans becoming blind, also helps explains the major economic impact it has on the United States. Glaucoma is responsible for costing the U.S. approximately 2.5 billion dollars annually (Covin, Laroche, & Olivier, 2014). A majority of this money is due to the 10 million annual hospital visits as a result of necessary glaucoma treatment (Covin, Laroche, & Olivier, 2014). Figure 1 chart explains how the expense of glaucoma can vary in the different stages of glaucoma, with each next stage being more costly as there are more hospital visitation. In the U.S. alone, there are approximately over 3 million people that have glaucoma with more than 120,000 individuals who become blind because of it (Glaucoma Research Foundation, 2017). However, on a worldwide scale, cases of glaucoma estimates to over 60 million (Glaucoma Research Foundation, 2017).Agent of disease, Mode of transmission, and SymptomsGlaucoma is caused by increased fluid pressure within the eye. There is no specific agent causing the development of glaucoma and because of this, there is no mode of transmission. However, if the drainage angle, or area where the fluid comes out from, becomes blocked and excess fluid cannot escape from the eye, fluid would build up and pressure within the eyes would rise; this would then result in glaucoma (Boyd, K., 2017). There are two common forms of glaucoma, including primary open-angle glaucoma (POAG) and angle-closure glaucoma (ACG). There are usually no visible signs or symptoms when it comes to POAG. Development of POAG is a slow progression that people may not be able to recognize or become aware of for years (Glaucoma Research Foundation, 2017). When a patient does become aware of vision loss, it is already quite advanced and cannot be reversed. As for ACG, there are a few noticeable symptoms including blurred vision, eye and head pain, nausea or vomiting, as well as sudden vision loss (Glaucoma Research Foundation, 2017). Host FactorsThere are multiple factors that can contribute to an individual’s vulnerability to developing glaucoma. Some of these important factors include race, age, family history, as well as just having the condition of diabetes. In terms of race, African Americans are particularly more at risk of developing glaucoma, even more so if they are over the age of 40 (Boyd, K., 2017). Those of Hispanic heritage also have an increased chance of developing glaucoma, especially if they are over 60 years of age (Boyd, K., 2017). These two group are just genetically more at risk compared to other groups. Figure 2 portrays the prevalence of glaucoma by different ethnic groups. In regards to age, those who are over 40 have a higher risk for glaucoma development (Boyd, K., 2017). The older population typically have decline in overall health which can be evident in their vision. Family lineage also plays an important role in determining glaucoma development. If immediate family members have glaucoma, the likelihood of glaucoma also increases. Additionally, those who have diabetes are more likely to develop glaucoma due to poor blood sugar control. Poor blood sugar control could damage blood vessels within the eyes, ultimately leading to glaucoma (American Academy of Ophthalmology, 2016).Socioeconomic and Temporal VariationWhile host factors do contribute to the vulnerability of glaucoma development, socioeconomic factors can explain why certain groups are more likely to be diagnosed with glaucoma than others. Studies have shown that socioeconomic status (SES) correlate with access to healthcare. Those with lower SES were more likely to be diagnosed with PACG while high SES individuals were more likely to be diagnosed to have POAG (Ko, Y.-C. et al, 2016). Those with lower SES typically have lower education levels which results in less shortsighted eye shift. Additionally, those with low SES may be short in height due to being malnutritious as children; short height is a risk factor for PACG (Ko, Y.-C. et al, 2016). As for the reason why there is a high diagnosis of POAG within high SES populations is because the only way to identify POAG is with eye examinations; this is a component not many low SES individuals regularly take part in because they cannot afford regular eye exams (Ko, Y.-C. et al, 2016). Figure 5 shows how diagnosis of glaucoma differs depending on SES.When it comes to temporal variations, there are studies that have shown that the winter season may have an effect on eye pressure, or intraocular pressure (IOP). Subjects in the month throughout the winter season, from November to February, experienced increased eye pressure as compared to the summer season; Figure 3 portrays the seasonal eye pressure (Blumenthal, Blumenthal, Peritz, & Best, n.d.). The winter months causes increase in eye pressure because when the weather drops to extremely cold temperatures, the human body and vision increases in pressure. More eye pressure can increase the chance of the development or the worsening of glaucoma.MechanismsGlaucoma is not a disease that is infectious and can spread to multiple individuals. It is a condition that is developed overtime within an individual. And because of that, mechanisms used to prevent the further development of glaucoma often including getting regular eye exams for early diagnosis. This is a preventative measure to help delay the progression of the disease. Glaucoma is permanent and cannot be undone. The only option available is to identify and diagnose the condition at the earliest of stages and help prevent further damage through medicine or surgery. Medication in the form of eye drops are used to help lower eye pressure and help in the prevention of vision loss (Boyd, K., 2017). In the case that eye drops are insufficient, oral medication is prescribed to help with the eye pressure (Boyd, K., 2017). Another eye pressure reducing treatment is surgery. Under surgery, there are multiple types including laser surgery or even drainage implant surgery. With laser surgery, a high-energy beam stimulates the fluid drain to release more fluid (American Optometric Association, n.d.). With drainage implants, a small tube is inserted in the eye to help with the release, or draining of fluid (American Optometric Association, n.d.). In the end, all treatment for glaucoma are life-long and must constantly be monitored with eye examinations and continuous follow-up treatments. Policies and their SignificanceTo address the issue of glaucoma and overall visual impairment within the U.S. population, there is an Eye Care Policy in place to assist individuals with receiving eye care services. Medicare and Medicaid are programs under the U.S. government to help those who are seniors, have disabilities, or have low income to receive eye care services (Unite for Site, n.d.). This is significant, because these populations often have trouble with the expenses when it comes to receiving eye care. VISION 2020 is a global health initiative in place with the purpose of eliminating preventable blindness by the year 2020 (American Optometric Association, n.d.). Developed under the World Health Organization, it aims to address the top causes of blindness including cataracts and glaucoma (American Optometric Association, n.d.). In order to help those who on the verge of becoming needlessly blind, the VISION 2020 plans to help with the development and implementation of national eye care programs. Under the VISION 2020 initiative, a Global Action Plan 2014-2019 was created to help reduce avoidable vision loss and secure eye care services around the world to help those who are visually impaired (American Optometric Association, n.d.). This initiative is significant because it is addressing the issue of preventative blindness from glaucoma, on a global scale. By ensuring everyone receives the best quality health care services is one key component of the Global Action Plan. Current HypothesisThere are quite a few hypotheses in the air about glaucoma. Two of the popular hypothesis that have emerged include the mechanical and ischemic theories. The mechanical theory explains that glaucoma is caused by increased eye pressure, or intraocular pressure, which then causes the squeezing of nerve fibers together, and disrupts the fluid drain flow (Disease Web, n.d.). The ischemic theory on the other hand, suggests that high intraocular pressure compresses the optic nerve head, and results in cell injury and thus glaucoma (Disease Web, n.d.). In the end, while there are many possible hypothesis, the main cause of what causes imbalance of fluid production, and thus increase of intraocular pressure, is unknown. Gaps in knowledgeWhen it comes to gaps in knowledge, there is no definite reason as to why glaucoma comes about. The only known information on causes is that glaucoma is due to an imbalance of fluid production which increase fluid pressure in the eyes. However, what the main cause is or why there is an imbalance to cause an increase fluid pressure is unknown. Furthermore, there is no information as to whether there are economic factors that can contribute to the development of glaucoma. While data such as Figure 4, can allow for assumptions that certain regions of the world, such as Africa, might have a high prevalence of glaucoma, it does not explain what in particular in those regions might influence a person’s likelihood of developing glaucoma. Additionally, when it comes to socioeconomic factors there is not much information or further explanation as to whether family structure or cultural background might contribute to glaucoma development. Not having a definite explanation of cause and contributory factor can be troubling and makes it harder to find solution for certain groups that display high prevalence of the condition. Further ResearchIn order to address these gaps in knowledge, researchers should do more experimentations and studies on what might be causing the imbalance of fluid production, whether it be economic factors, socioeconomic factors, or temporal variation factors. Epidemiologist should examine and do a comparison of multiple races/ethnicities to determine if there is a cultural significance that might play a role in why certain races/ethnicities are more prone in developing glaucoma instead of just contributing it genetic factors. For example, they could examine diets or lifestyle to see if there is an unknown extraneous factor. By finding specific causes, certain groups can take action and try to change their behavior to prevent the development of glaucoma. ReferencesAmerican Optometric Association (n.d.). Glaucoma. Retrieved from Academy of Ophthalmology (2016, November 4) Who is at Risk for Glaucoma? Retrieved from Academy of Ophthalmology (n.d.) Vision 2020. Retrieved from , M., Blumenthal, R., Peritz, E., & Best, M. (n.d.). Seasonal Variation in Intraocular Pressure.?American Journal of Ophthalmology,69(4), 608-610. doi:10.1016/0002-9394(70)91628-4Boyd, K. (2017, March 1) Causes of Glaucoma. American Academy of Ophthalmology. Retrieved from , K. (2017, March 1) Glaucoma Treatment. American Academy of Ophthalmology. Retrieved from , K. (2017, March 1) Who is at Risk for Glaucoma? American Academy of Ophthalmology. Retrieved from , Y. N., MD, Laroche, D., MD, & Olivier, M. M., MD. (2014, July & Aug.). The Societal Costs of Blindness From Uncontrolled Glaucoma. Glaucoma Today. Retrieved from Web (n.d.). Glaucoma. Retrieved from , Y.-C., Hwang, D.-K., Chen, W.-T., Lee, C.-C., & Liu, C. J. (2016). Impact of Socioeconomic Status on the Diagnosis of Primary Open-Angle Glaucoma and Primary Angle Closure Glaucoma: A Nationwide Population-Based Study in Taiwan.?PLoS ONE,?11(2), e0149698. Research Foundation (2017, October 29). Glaucoma Facts and Stats. Retrieved from Research Foundation (2017, October 29). What are the Symptoms of Glaucoma? Retrieved from for Site (n.d.). Eye Care Policy in the United States. Retrieved from AFig 1: The cost of glaucoma patients at different stages of glaucoma BFig 2: The prevalence of glaucoma in terms of ethnic groups. CFig. 3: Graph of the eye pressure (or intraocular pressures) in 2 month periods. DFig 4: age-specific prevalence of glaucoma by world regions and ethnic groups. EFig 5: Diagnosis of Glaucoma in relation to SES ................
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