Background Retinopathy of prematurity (ROP) is a severe complication of preterm birth and can lead to severe visual impairment or even blindness if untreated. The incidence of ROP requiring treatment is increasing in some developed countries in conjunction with higher survival rates at the lower end of gestational age (GA).

Material and methods The incidence of ROP and severe ROP (sROP) requiring treatment in Switzerland was analysed using the SwissNeoNet registry. We conducted a retrospective cohort analysis of very preterm infants with a GA below 32 weeks who were born between 2006 and 2015 in Switzerland. Patient characteristics were stratified according to GA.

Results 9.3% and 1.8% of very preterm infants in Switzerland developed ROP of any stage and sROP, respectively. The incidence of ROP treatment was 1.2%. Patients with 24 and 25 weeks GA had the highest proportion of ROP treatment at 14.5% and 7.3%, respectively, whereas the proportion of treated infants at or above a GA of 29 weeks was 0.06%. Similarly, the risk of sROP declined strongly with increasing GA. During the observation period of 10 years, the incidence of ROP treatment ranged between 0.8% and 2.0%. Incidences of sROP or ROP treatment did not increase over time.

Conclusion The incidence of ROP treatment in Switzerland is low and was stable over the analysed period. The low incidence of sROP in patients with a GA of 29 weeks or more leaves room for a redefinition of ROP screening criteria.