Background/aim: To investigate the biometric components and refractive errors in premature infants with or without retinopathy of prematurity (ROP). Materials and methods: Anterior chamber depth, lens thickness, vitreous length, and axial length were measured with an ultrasound biometer. Cycloplegic refraction was performed by streak skiascopy. Infants with or without ROP were grouped according to postmenstrual age at the time of ocular examination: Group 1, ≤33 weeks; Group 2, 34-37 weeks; Group 3, 38-41 weeks; Group 4, 42-45 weeks; Group 5, ?46 weeks. Results: The mean postnatal age of 894 infants (451 females and 443 males) was 8.7 ± 4.5 weeks, gestational age was 30.9 ± 2.8 weeks, and birth weight was 1506 ± 484 g. In Group 2, the mean vitreous length and axial length of infants with ROP were significantly lower than those of infants without ROP (P = 0.011, P = 0.001). The mean anterior chamber depth, lens thickness, spherical equivalent, and astigmatism in all groups did not differ significantly among the infants with or without ROP (P > 0.05). Conclusion: The anterior chamber depth, lens thickness, vitreous length, and axial length showed a linear growth throughout the follow-up period. The maximum elongation was observed in vitreous length and axial length.