AIM: To investigate the axial length(AL)of normal premature infants, and to analyze the associations with gender, gestational age, birth weight, and postmenstrual age and other ocular biometry parameters.

METHODS: To analyze AL and other relevant data obtained from the first examination within 4-6wk after birth, 400 cases(800 eyes)of normal preterm infants were included who were screened for retinopathy of prematurity(ROP)in Department of Ophthalmology of Northwest Women and Children Hospital from March 2016 to October 2016.

RESULTS: Totally 400 cases(800 eyes)of normal preterm infants were included in this study, while the AL of right and left eyes were respectively 16.11±0.58mm and 16.13±0.53mm, with no statistically significant difference(P>0.05). Therefore, the mean value(16.12±0.55mm)of the binocular AL was taken as the AL of the group. In this study, AL differences of premature infants between different genders were not statistically significant(P>0.05). Pearson correlation analysis showed that AL was positively correlated with the gestational age, birth weight, postmenstrual age, anterior chamber depth and vitreous length(r=0.427, 0.401, 0.635, 0.691, 0.878; P<0.01), and negatively correlated with lens thickness(r=-0.153, P<0.01). By incorporating the above factors into the multiple linear regression analysis, it was found that AL was significantly correlated with gestational age, anterior chamber depth, and vitreous length, and the regression equation Y=4.109+0.029X₁+0.481X₂+0.978X₃(Y=AL, X₁=gestational age, X₂=anterior chamber depth, X₃=vitreous length)was obtained.

CONCLUSION: In the early stage of normal premature infants, the mean AL was 16.12±0.55mm, which was not related to gender, but positively correlated with gestational age, birth weight, postmenstrual age, anterior chamber depth, and vitreous length, and negatively correlated with lens thickness.