Refractive error in premature infants without retinopathy of prematurity and full-term infants aged 1-18 months: a propensity score matching analysis

Abstract Background Premature birth signals increased risk for abnormal refractive development even without retinopathy of prematurity (ROP). This study aim to evaluate the differences in refractive error between premature infants without ROP and full-term infants, and to assess the relationship between physical parameters on birth and refractive status in premature infants. Methods A total of 1205 infants aged 1–18 months participated in this cross-sectional study at Tianjin Women’s and Children’s Health Center in China from February 2019 to September 2021. Propensity score matching (PSM) was used to balance the covariates between preterm infants without ROP and full-term infants, and the differences in refractive error between the two groups were compared to further analyze the gestational age (GA) of preterm infants, birth weight (BW), and birth length (BL). We exploited a simple linear regression model to determine the relationships between diopter and GA, BW, and BL in preterm infants. Results Of all participants, 230 pairs were successfully matched based upon propensity scores. MSE of preterm infants without ROP tended to be lower than that of full-term infants, but the overall difference was not statistically significant (P = 0.749). Compared with full-term infants, preterm infants without ROP also exhibited significantly higher prevalence of refractive error (69.1% vs. 79.1%, P = 0.014), emmetropia (8.3% vs.13.9%, P = 0.037), and astigmatism (47.4% vs. 56.1%, P = 0.040). While MSE was negatively correlated with BW and BL (R2 = 0.260, P < 0.001; R2 = 0.035, P = 0.004), there was no correlation between MSE and GA (R2 = 0.048, P = 0.051). Conclusions Compared with full-term infants, premature infants without ROP manifested higher prevalence of refractive error. The diopter of premature infants without ROP were significantly correlates better with BW more than it did to GA and BL, therefor BW was considered to evaluate the early refractive status of premature infants.