The evolution trendency of high myopia in 308 school children of Xi-an city

Abstract

Objective To observe the eyes' refractive status,especially the evolution tendency of high myopia in Xi'an city schoolchildren of China. Methods The cross-sectional study was conducted in the 308 schoolchildren of 615 eyes in Xi' an city schools.The inclusion criteria on was ＞-6D of the spherical equivalent refraction.The object ophthalmic examinations were done on all participants,which included non-cycloplegic objective refraction,visual acuity,ocular pressure,fundus evaluation by special trained ophthalmologists and nurses.The special designed inventory scale was filled in and input special computer program,then the data were statistically analyzed with SPSS10.0. Results 1.In the 5757 students of 11514 eyes,whose ages were between 7-18 years,the detective rate of myopia was 81.4％ (9376 eyes) and the high myopia 5.3％ (615 eyes).Of high myopia,the right eye was 2.6％ (300 eyes),the left was 2.7％ (315 eyes),and the boys 2.4％ (275 eyes),the girls 3.0％ (340 eyes).Among 12 grades,the detective rate of high myopia groups were significantly increased with the age's growing,including 0.9％ in 1st grade of primary school and 1.6％ in 6th grade of primary school,8.0％ in 3rd year of junior middle school,and 12.5％ in 3rd year of senior middle school.The average detective rates were 1.1％ and 7.7％ separately in 6-year' primary school and middle school.The average detective rates were 0.8％,1.6％,4.9％,12.3％ by sequence in 3-year' junior primary school,senior primary school,junior middle school and senior middle school.2.The average refractive error of spherical equivalent refraction was (-7.43±1.29)D with 95％ confidence interval (-7.54,-7.33)D.Among 12 grades,there were significant differences (P =0.009),the 1st grade of primary school was (-7.26±0.62)D,the 6th grade of primary school (-6.95±0.58)D,the 3rd year of junior middle school was (-7.41±1.37)D,the 3rd year of senior middle school was (7.30±1.13D.3.The average refractive error in 6-year primary school was (-6.97±0.6)D with 95％ confidence interval (-7.16,-6.78)D,while in middle school was (-7.47±1.33)D with 95％ confidence interval (-7.58,-7.36)D,there was significant difference (P =0.011) between them. 4.The average refractive error in 3-year junior and senior primary school,junior and senior middle school were (-6.88±0.60)D with CI (-7.19,-6.57)D,(-7.02±0.68D with CI (-7.27,-6.77)D,(-7.45±1.41)D with CI (-7.63,-7.26)D,and (-7.49±1.28)D with CI (-7.62,-7.35)D by sequence (P =0.080).5.There were no differences between right or left eyes and gender (P ＞0.05).6.The distribution was in lower level of-6D,in primary school,and,up to a higher level of-8D,in junior middle school,and to -13D in junior and senior middle school. Conclusions There is continuous increasing trend in high myopia' constitute during 12-year schoolchildren,in which it shows an increase by leap type between senior primary and junior middle school stage,and between junior and senior middle school stage.The distribution of high myopia is in lower level of -6D,in primary gage and goes up to a higher level of -8D,in junior middle school stage,while progressing to -10D in senior middle school which means high risk of pathologic myopia formation during their late lifespan.The key stage is in their adolescent development state between 14 to 18 years old with a pathological significance. Key words: Schoolchildren ;  High myopia ;  Myopia ;  Detective rate ;