Retinopathy of prematurity: postmenstrual age at threshold in a transitional economy is similar to that in developed countries

Background: To analyse the timing of threshold disease in infants requiring treatment for retinopathy of prematurity in a transitional economy. Methods: Design: Retrospective, observational, cohort study. Setting: National Hospital of Paediatrics, Hanoi, Vietnam. Study population: Premature infants in the Neonatal ward requiring laser treatment for threshold retinopathy of prematurity. Main outcome measures: Chronological age and postmenstrual age at treatment. Results: From January 2002 to November 2004, 42 infants from the National Hospital of Paediatrics required laser surgery for threshold retinopathy of prematurity. The mean ± standard deviation (SD) of birth weight was 1369 ± 184 g (range 1000–1700); the mean ± SD of gestation at birth was 30 ± 1.8 weeks (range 27–34); and the mean ± SD of postmenstrual age at which treatment occurred in these infants was 36.2 ± 2.5 weeks (range 31.4–42). A further 58 infants were transferred from other hospitals for laser surgery between January 2004 and October 2004. The mean ± SD of birth weight was 1325.5 ± 237.2 g (range 800–1900); the mean ± SD of gestation at birth was 30 ± 1.7 weeks (range 28–35); and the mean ± SD of postmenstrual age at which treatment was given in these infants was 36.3 ± 2.3 weeks (range 32.71–44.3). Discussions: Despite the relative maturity of the gestation of these infants compared with infants in developed countries who develop severe retinopathy of prematurity, the timing of treatment for threshold disease appears to be related to postmenstrual age.