Distribution of refractive errors (better eye) by age and gender
| Boys | Age (years) | P value comparing different ages | |||
| 5–9 (n=12 470) | 10–14 (n=28 377) | 15–18 (n=13 985) | Total (n=54 832) | ||
| SE (D) | n (%) | ||||
| <−6.0 | 155 (1.24) | 371 (1.31) | 208 (1.49) | 734 (1.34) | <0.001 |
| <−3.0 to −6.0 | 308 (2.47) | 1455 (5.13) | 1133 (8.10) | 2896 (5.28) | |
| <−0.5 to −3.0 | 3866 (31.00) | 10 564 (37.23) | 6231 (44.55) | 20 661 (37.68) | |
| ≥−0.5 to ≤+0.5 | 5328 (42.73) | 12 223 (43.07) | 5288 (37.81) | 22 839 (41.65) | |
| >0.5 to 2.0 | 1873 (15.02) | 2584 (9.11) | 866 (6.19) | 5323 (9.71) | |
| >2.0 | 940 (7.54) | 1180 (4.16) | 259 (1.85) | 2379 (4.34) | |
| Median refractive error (D) (first and third quartiles) | −0.25 (−0.88, 0.25) | −0.50 (−1.25, 0.00) | −0.75 (–1.63, 0.25) | −0.50 (–1.5, 0.50) | <0.001 |
| Range | −18 to 13.0 | −20.5 to 16.0 | −20.75 to 19.0 | −20.75 to 19.0 | |
| Median cylinder (D) (first and third quartiles) | −1.0 (–1.75, –0.50) | −0.75 (–1.25, –0.50) | −0.75 (–1.00, –0.50) | −0.75 (–1.50, –0.50) | <0.001 |
| Range | −7.75 to 0 | −7.75 to 0 | −7.75 to 0 | −7.75 to 0 | |
| Girls | 5–9 (n=11 014) | 10–14 (n=31 767) | 15–18 (n=19 103) | Total (n=61 884) | |
| SE (D) | n (%) | ||||
| <−6.0 | 114 (1.04) | 382 (1.20) | 280 (1.47) | 776 (1.25) | <0.001 |
| <−3.0 to −6.0 | 255 (2.32) | 1822 (5.74) | 1723 (9.02) | 3800 (6.14) | |
| <−0.5 to −3.0 | 3429 (31.13) | 11 662 (36.71) | 8244 (43.16) | 23 335 (37.71) | |
| ≥−0.5 to ≤+0.5 | 4839 (43.93) | 14 232 (44.80) | 7590 (39.73) | 26 661 (43.08) | |
| >0.5 to 2.0 | 1647 (14.95) | 2700 (8.50) | 973 (5.09) | 5320 (8.60) | |
| >2.0 | 730 (6.63) | 969 (3.05) | 293 (1.53) | 1992 (3.22) | |
| Median refractive error (D) (first and third quartiles) | −0.25 (−0.86, 0.25) | −0.50 (−1.25, 0.00) | −0.75 (−1.75, –0.25) | −0.5 (−1.25, –0.50) | <0.001 |
| Range | −21.75 to 18.86 | −21.75 to 13.0 | −20.75 to 15.25 | −21.75 to 18.86 | |
| Median cylinder (D) (first and third quartiles) | −1.0 (−1.50, –0.50) | −0.75 (−1.00, –0.50) | −0.5 (−1.00, –0.50) | −0.75 (−1.25, –0.50) | <0.001 |
| Range | −7.75 to 0 | −7.75 to 0 | −6.5 to 0 | −7.75 to 0 | |
| Overall | 5–9 (n=23 484) | 10–14 (n=60 144) | 15–18 (n=33 088) | Total (n=116 716) | |
| SE (D) | n (%) | ||||
| <−6.0 | 269 (1.15) | 753 (1.25) | 488 (1.47) | 1510 (1.29) | <0.001 |
| <−3.0 to −6.0 | 563 (2.40) | 3277 (5.45) | 2856 (8.63) | 6696 (5.74) | |
| <−0.5 to −3.0 | 7295 (31.06) | 22 226 (36.95) | 14 475 (43.75) | 43 996 (37.69) | |
| ≥−0.5 to≤+0.5 | 10 167 (43.29) | 26 455 (43.99) | 12 878 (38.92) | 49 500 (42.41) | |
| >0.5 to 2.0 | 3520 (14.99) | 5284 (8.79) | 1839 (5.56) | 10 643 (9.12) | |
| >2.0 | 1670 (7.11) | 2149 (3.57) | 552 (1.67) | 4371 (3.74) | |
| Median refractive error (D) (first and third quartiles) | −0.25 (−0.86, 0.25) | −0.50 (−1.25, 0.00) | −0.75 (−1.75, –0.25) | −0.5 (−1.25, 0.00) | <0.001 |
| Range | −21.75 to 18.86 | −21.75 to 16.0 | −20.75 to 19.0 | −21.75 to 19.0 | |
| Median cylinder (D) (first and third quartiles) | −1.0 (−1.50, –0.50) | −0.75 (−1.25, –0.50) | −0.5 (−1.00, –0.50) | −0.75 (−1.25, –0.50) | <0.001 |
| Range | −7.75 to 0.00 | −7.75 to 0.00 | −7.75 to 0.00 | −7.75 to 0.00 | |
D, diopter; SE, spherical equivalent.