Essay: Prevalence of myopia in China, Japan and Taiwan

(Draft)
1. China
The prevalence of myopia is especially high among Chinese and Japanese(citation). In China, the increased in the prevalence in myopia is largely seen in the urban cities more than a rural area, it may due to the large population or it may result from the lifestyle and the educational level. The cities that showed a high level of myopia are Guangzhou(He urban) and Hong Kong(Goh and Lam, 1994; Lam et al., 1994). Guangzhou study was done on a very large sample about 5053 children aged 5 and 15 years. The prevalence of myopia was 73.1% for children 15 years old and 3.3% in 5 years old. Also, the study found females had a higher risk of myopia. (citation He). However, there are some studies reported lower value as seen in Shunyi(citation), where the study was done on school-aged children and the prevalence of myopia was found to be 55% in females and 36.7% in males(citation). Another study was done on both rural and urban area in Xiamen and Singapore, the myopia rates were higher in Singapore 12.3% compared to Xiamen both rural 3.9% and urban area 9.1%. (citation Zhan 2000). Both Shunyi and Xiamen studies done on younger children and that’s why the prevalence was smaller.
The school-aged children in Hong Kong appeared to have increased in the prevalence of myopia(we Edward). This increase in the prevalence of myopia is also seen across the adult population (Goh andLam, 1994; Lam et al., 1994). The prevalence of myopia was frequent (71%) in this group of adults with the mean spherical equivalent refraction of -3.00 DS (Goh andLam, 1994). A study done to investigate the change of. Refracrive error on period of 10 years on older population more than 40 years. A significant shift to myopia may due to nuclear sclerosis (lee et al ). We and Edward (1999) have investigate the prevalence of myopia and the genetic link between three genertation on different area in China, Hong Kong, Tianjin and rural area Ban Chau. The prevalence of myopia is sginfcantly vary in these areas. The higher prevalence reported in urban area. Again in all cities the prevalence of myopia increased in the next generation.
2. Japan
Japan is one of the countries that reported a high rate in the prevalence of myopia among their population. The increase rate was noticed between school children(sato 1957** ). After the second world war the myopia rate has been increased steadily. The prevalence of myopia has increased to 50% in student population(Population studies – myopia experience in Japan). The time prior second world war the changes in living standers and changes in the education are leading to increase in the myopia rates between students(kamaya 1985). a study was aimed to investigate the prevalence of myopia btween 1984 and 1996 on student from 3 to 17 years. The results support that rate has increased from 49.3% to 65.6% in 17 year old student from 1984 to 1996.( prevalence of myopia 3 to 17). Previous studies have also investigated the prevalence of myopia, a study in 1977 found myopia to be 12.5% of the primary school students and 37.6 of the junior high school students(MARUO, 1977). Where in 1984 another study reported that 54% of the student aged between 15 to 17 years old had myopia.(ctitation)
3. Taiwan
The increased in the level of education system and the changes in the environmental factors are contribute in the prevalence of myopia in Taiwan. Today Taiwan and most of Asia countries have a higher rate of myopia. In Taiwan several years ago myopia was not a problem, in 1944 a study indicates that 80% of sampled population were emmetrope.(citiation on paper 1984). The civilization impacts on the severity of myopia among their population. The rate of myopia and high myopia has increased between school aged students age 7 to 13 years(Taiwanese schoolchildren:1983 to 2000.). Moreover the age of the onset of myopia was become at very young age which reflect the direct effect of environmental factors(same reference as before). National wide survey was done in 2000 and they compared the finding with survey in 1995, the prevalence of myopia was higher than previous study in 1995. The rate of myopia has increased from 12% in 1995 to 20% in 2000 for the students aged 7 years old. At 12 years old students, the myopia prevalence increased from 56% to 61%. At the age of 16 to 18 the rate was remain stable at around 84%. It was believed that increasing may due to the change in the academic level and spend more tine on near work task(epidemiology study prevalence of myopia 2000)
The prevalence of myopia in urban areas were higher than rural areas. This marked difference found in between Chinese and Aboriginal population in Taiwan( lin et al 1988, chang et el how genetic). However the myopia progression has increased in all areas and in all populations.
Lin, L.L., Hung, P.T., Ko, L.S., Hou, P.K., 1988b. Study of myopia
among aboriginal school children in Taiwan. Acta Ophthalmol.
185 (Suppl.), 34–36.
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