Journal List > J Korean Ophthalmol Soc > v.48(8) > 1007907

Han, Kang, Jun, and Choi: Changes of Refractive Errors and Optometric Values in Fourth Graders at an Urban Elementary School in Korea

Abstract

Purpose

To evaluate changes in refractive errors and quantify optometric values in 4th graders at an urban elementary school in Korea.

Methods

A total of 188 school children (376 eyes) were assessed in a population-based, cross-sectional and longitudinal follow-up study between March and December 2003. Uncorrected visual acuity, best corrected visual acuity, corneal refractive power measured with auto keratometer (KR-8100, Topcon® Inc., Japan), axial length measured with A-scan ultrasound biometry (A/B-scan system 835, Humphrey® Inc., Dublin, CA), and cycloplegic refraction were evaluated on March and December, respectively.

Results

Mean visual acuity decreased from −0.15±0.29 LogMAR to −0.20±0.35 LogMAR and mean spherical equivalent (SE) showed myopic progression from −0.65±1.57 diopter (D) to −0.88±1.75D. The prevalence rate of myopia (<-0.50D SE) was increased from 44.1% to 50.3%, while that of hyperopia (> +1.00D SE) was decreased from 8.0% to 5.8%. Mean corneal refractive power changed from 43.21±1.29D to 43.35±1.31D, and mean axial length changed from 23.38±0.88 mm to 23.60±0.92 mm, respectively.

Conclusions

We assessed the changes of refractive errors and quantified the optometric values in a population-based, longitudinal follow-up study. The results showed that the prevalence of myopia and the mean axial length increased during our study in urban elementary 4th graders in Korea.

References

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Table 1.
Comparison of uncorrected visual acuity using logMAR between March and December
[No. of eyes (%)]
  March December Difference p-value
Total
Uncorrected visual acuity (logMAR, mean±SD) -0.15±0.29 -0.20±0.35 -0.05±0.16 < 0.0001
Group of logMAR
  0≦ 200 (53.2) 181 (48.1)   0.0152
  -0.5 ≦ <0 112 (29.8) 113 (30.0)    
  -1.0≦ < −0.5 64 (17.0) 71 (18.9)    
  -1.5 ≦ <-1.0 0 (0.0) 10 (2.7)    
  -2.0≦ <-1.5 0 (0.0) 1 (0.3)    
Boys
Uncorrected visual acuity (logMAR, mean±SD) -0.11±0.25 -0.15±0.30 -0.04±0.15 0.0009
Group of logMAR
  0≦ 107 (56.3) 100 (52.6)   0.4257
  -0.5 ≦ <0 60 (31.6) 57 (30.0)    
  -1.0≦ <-0.5 23 (12.1) 32 (16.8)    
  -1.5 ≦ <-1.0 0 (0.0) 1 (0.5)    
  -2.0≦ <-1.5 0 (0.0) 0 (0.0)    
Girls
Uncorrected visual acuity (logMAR, mean±SD) -0.19±0.32 -0.25±0.40 -0.06±0.18 < 0.0001
Group of logMAR
  0≦ 93 (50.0) 81 (43.6)   0.0263
  -0.5 ≦ <0 52 (28.0) 56 (30.1)    
  -1.0≦ <-0.5 41 (22.0) 39 (21.0)    
  -1.5 ≦ <-1.0 0 (0.0) 9 (4.8)    
  -2.0≦ <-1.5
0 (0.0)
1 (0.5)
 
 
Total 376 (100.0) 376 (100.0)    

: statistical significance was tested by paired t-test.

: statistical significance was tested by chi-square test.

Table 2.
Comparison of refractive error between March and December
[No. of eyes (%)]
  March December Difference p-value
Total
  Refractive error (Diopter, mean±SD) -0.65±1.57 -0.88±1.75 -0.23±0.67 <0.0001
 
  Myopia (≦ −0.5D) 166 (44.2) 188 (50.1)   0.2295
  Emetropia (-0.5D< <1.0D) 180 (47.9) 165 (43.9)    
  Hyperopia (1.0DS) 30 (7.9) 23 (6.0)    
Boys
  Refractive error (Diopter, mean±SD) -0.50±1.54 -0.76±1.67 -0.26±0.76 <0.0001
 
  Myopia (≦-0.5D) 79 (41.6) 93 (48.9)   0.3159
  Emetropia (-0.5D< <1.0D) 96 (50.5) 86 (45.3)    
  Hyperopia (1.0D≦) 15 (7.9) 11 (5.8)    
Girls
  Refractive error (Diopter, mean±SD) -0.82±1.58 -1.01±1.82 -0.19±0.56 <0.0001
 
  Myopia (≦-0.5D) 87 (46.8) 95 (51.1)   0.6576
  Emetropia (-0.5D< <1.0D) 84 (45.2) 79 (42.5)    
  Hyperopia (1.0D≦)
15 (8.0)
12 (6.4)
 
 
Total 376 (100.0) 376 (100.0)    

: statistical significance was tested by paired t-test.

: statistical significance was tested by chi-square test.

Table 3.
Comparison of axial length between March and December
(mm)
  March (mean±SD) December (mean±SD) Difference (mean±SD) p-value
Boys 23.53±0.85 23.75±0.89 0.22±0.15 < 0.0001
Girls 23.23±0.88 23.44±0.92 0.21±0.25 < 0.0001
Total 23.38±0.88 23.60±0.92 0.22±0.21 < 0.0001

: statistical significance was tested by paired t-test.

Table 4.
Comparison of corneal refractory power between March and December
[diopter (D)]
  March (mean±SD) December (mean±SD) Difference (mean±SD) p-value
Boys 43.08±1.23 43.24±1.24 0.15±0.29 < 0.0001
Girls 43.35±1.34 43.46±1.38 0.11±0.46 0.0010
Total 43.21±1.29 43.35±1.31 0.13±0.38 < 0.0001

: statistical significance was tested by paired t-test.

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