Incidence, Risk Factors and Development of Retinopathy of Prematurity in Mid-Preterm and Late-Preterm Infants

Purpose: To evaluate the incidence, risk factors, and development of retinopathy of prematurity (ROP) in midpreterm and late-preterm infants born at 32 to 36 6/7 weeks of gestational age. Methods: The ophthalmic examination findings and risk factors of 5,477 preterm infants who underwent ophthalmological examination were evaluated retrospectively. The rates of any stage and severe ROP (requiring treatment) development and treatment options were recorded. The risk factors were analyzed by using logistic regression analysis. Results: A total of 5,477 infants were included in the study, of whom 2,715 (49.57%) were mid-preterm and 2,762 (50.43%) were late-preterm.The rates of any stage and severe ROP were 8.2% (n = 223) and 0.6% (n = 15) in mid-preterm infants, respectively. In late-preterm infants, the rate of any stage ROP was 2.1% (n = 59), and no severe ROP was detected. There was no significant difference in mean birth weight in mid-preterm infants between infants with any stage ROP and severe ROP (P = .104). Of the 15 infants (0.3%) who required treatment, 14 (0.2%) infants had laser photocoagulation, 1 (0.01%) had intravitreal bevacizumab, and 2 (0.03%) had additional therapy (laser photocoagulation and intravitreal bevacizumab). In logistic regression analysis, a significant association was found between treatment requirement and transport from an external center (P < .001, beta = 0.04). Conclusions: Although ROP development rates decrease as birth weight and gestational age increase, late-preterm infants should be examined for ROP at least once, especially those born in low-income countries because ROP development can still be observed.