[A longitudinal study on the progression and influencing factors of myopia in primary school students from grade one to grade three in Hubei Province].

Objective: To investigate the longitudinal epidemiological characteristics of myopia in primary school students from grade one to grade three in Hubei province, and to analyze the main factors affecting the occurrence and development of myopia, so as to provide the direction and theoretical basis for the prevention and control of myopia in children and adolescents. Methods: Longitudinal study. A total of 13, 244 primary school students from grade one to grade three in 17 prefectures and forest districts of Hubei province were included in the study by means of random stratified cluster sampling. Among them, there were 7, 331 boys and 5, 913 girls with an age of (7.7±1.0) years. The same group of students were followed up for two years from October 2017 to October 2019 to complete three data collections. All included subjects underwent visual acuity examination, which required further automatic computer optometry after using cyclopentolate hydrochloride eye drops if the visual acuity was less than 1.0. In the questionnaire, the general situation and eye behavior of the included subjects were collected. The Chi-square test was used to compare the prevalence of myopia among different genders,different reproductive history and grades. The Kruskal-Wallis H test was used to compare the difference in the mean spherical equivalent refraction, and logistic regression was used to analyze the influencing factors of myopia. Results: The prevalence of myopia was 23.10% at baseline in 2017, 28.67% after one year's follow-up and 33.26% after two years' follow-up among primary school students in grade one to grade three in Hubei province. The overall prevalence of myopia increased with time (χ²=307.47, P<0.05). It also increased with the increase of grades. After two years of follow-up, the myopia rate of students in grades one through three was 25.62%, 35.07% and 41.05%, respectively (χ²=200.98, P<0.05). In 2017, the prevalence of myopia was 21.62% in boys and 24.93% in girls, and it increased to 31.20% and 35.69% after 2 years of follow-up, respectively. Both the prevalence of myopia and the spherical equivalent refraction were higher in girls than in boys. Moreover, myopia was associated with parents' myopia (OR=1.17), less time for outdoor activities (OR=1.06), no rest after half an hour's study (OR=1.18), more time for daily exposure to electronic products (OR=1.07), longer time for extracurricular study (OR=1.09), and higher grades (OR=1.78). Children whose parents were more myopic and who ate sweets and fizzy drinks more often had greater levels of myopia. Conclusions: Myopia occurs early in primary school students of grade one to grade three in Hubei province and increases rapidly. More attention should be paid to good habits for eyes, regular screening, outdoor activities and girls. (Chin J Ophthalmol, 2021, 57: 749-756).

[The epidemiology of myopia in primary school students of grade 1 to 3 in Hubei province].

Objective: To investigates the visual condition and myopia status in primary school students of grade 1 to 3 in Hubei province and to further analyze the influencing factors of myopia, so as to provide theoretical basis for prevention and control of myopia. Method: Cross-sectional study. A total of 18 532 primary school students from grade 1-3 in 26 primary schools from 17 prefecture-level cities in Hubei province were included in the study from March 2017 to July 2017, by using a random stratified cluster sampling method. In this study, 16 955 people were actually surveyed, with a response rate of 91.49%. All students' Visual acuity was measured, a further retinoscopy refraction test after application of Cyclopentolate Hydrochloride Eye Drops was conducted for those whose visual acuity was less than 5.0. The general situation and eye behavior of all students were investigated by questionnaires. Chi-square test was used to compare the prevalence of myopia between different grades, different regions and different genders, as well as the distribution of myopia correlation between different regions, and Logistic regression model was used to analyze the correlation between myopia and related factors. Results: The prevalence of myopia among primary school students of grade 1 to 3 in Hubei province is 24.15% with 12.67% in the first grade, 24.91% in the second grade, 34.95% in the third grade, and the difference was statistically significant (χ(2)=862.28, P<0.05). According to the study, mild myopia is the most prevailing condition among myopia students, with the prevalence rate of mild myopia, moderate myopia and severe myopia being 19.21%,4.29%, and 0.64% respectively, and the difference is statistically significant (χ(2)=155.62, P<0.05). In addition, the prevalence of myopia is different in each region, which was highest in provincial capitals, followed by non-provincial cities, and the lowest in rural areas, with statistically significant difference (χ(2)=539.57, P<0.05). Myopia is generally related to multiple factors, such as the grade, parents' myopia, outdoor activities, continuous closing reading, exposure to electronic products, and extracurricular reading time are related to myopia (P<0.05). Conclusions: Children's myopia is a public health problem that should not be ignored. The prevalence of myopia among 1-3 grade pupils is 24.15% with an increasing tendency with grade. The occurrence of myopia is related to heredity and eye behavior. (Chin J Ophthalmol, 2018, 54:756-761).

[Immune response of rubella vaccine in the populations with different age groups].

The natural immunity status in different age groups was investigated. The positive rate of HI antibody under the age of 4 was less than 25%. The natural immunity level increased gradually with age and the positive rate of the antibody reached 80% among the group aged 13-25. Rate of seroconversion was 100% in any age group one month after immunization, and GMT rose from 13.33 to 243.16. It was suggested that immunogenicity of domestic attenuated live rubella vaccine BRD II was satisfactory. For the population with positive-antibody before immunization, the total GMT rose from 189.59 to 259.00 after vaccination and the difference between immunization before and after was highly significant. According to the above result, we suggested that the vaccination strategy for rubella among young children and women of child-bearing age should be implemented.