METHODS: A retrospective study with large sample was conducted. Sex, age and eye axial length of children and adolescent aged 4 to 22 with refractive errors who visited Dongguan Guangming Ophthalmological Hospital from 2009 to 2018 were collected. A total of 26 113 patients(52 226 eyes)were enrolled. Axial length data were analyzed statistically in three dimensions, including gender, laterality and age.

RESULTS: Among the children and adolescent aged 4 to 22 with refractive errors in Dongguan Area, axial length of female group was shorter than male group(t=34.297, P<0.001). The shorter axial length of left eye was observed in the group aged 10 to 22(t=5.362, P<0.001). There were two peaks in the growth rate of axial length: 7-8 years old and 18 years old respectively. A linear regression formula was derived: axial length in male group(mm)=21.97+0.224×age(F=14352.9, P<0.001 adjusted R2=0.332), axial length in female group(mm)=21.40+0.234 ×age(F=12491.9, P<0.001 adjusted R2=0.349).

CONCLUSION: Among the children and adolescent aged 4 to 22 in Dongguan, the average axial length of female is shorter than male. The increase of axial length were observed in the right eye compared to the left eye starting from the age of 10, the growth rate of axial length is faster in two age groups: 7 to 8 years old and 18 years old.