AIM: To investigate the refractive state and related factors of low birth weight infants aged 3-6 years old.

METHODS: During the study period from March to June 2018, 144 cases of low birth weight infants in 8 kindergartens were randomly selected as study group. The normal birth weight of the same kindergarten was randomly selected according to the 1:1 pairing principle as control group. The refractive status and eye biometrics of the two groups were compared. The factors related to the equivalent spherical power of low birth weight were analyzed.

RESULTS: Among the children of all ages, the spherical degree and the equivalent spherical degree of the study group were lower than the control group. The corneal curvature was higher than that of the control group. There were significant differences of the axial length and the cylindrical degree between the two groups for 5-6 years old children(P<0.05). After multiple regression, the equivalent spheroscopy degree =-10.491-0.442×age+0.765×gestational age+5.860×birth weight-1.529×axial length +0.547×corneal curvature(R²=0.823, P<0.001).

CONCLUSION: The trend of myopic refractive error and astigmatism in children with low birth weight of 3-6 years old is higher than that of normal birth weight. The refractive error is closely related to age, gestational age, birth weight, axial length and corneal curvature, which requires early monitoring and intervention.