Incidence of retinopathy of prematurity in extremely premature infants over an 18-year period

Background: To report the incidence of retinopathy of prematurity (ROP) in a subgroup of extremely premature infants admitted to an Australian tertiary centre over an 18-year period. Design: Retrospective study. Royal Brisbane and Women's Hospital Neonatal Intensive Care Unit. Participants: Five hundred and fifty-four infants admitted between 23 and 25.6weeks gestational age (GA). Methods: The 18-year study was divided into three 6-year periods for analysis: period 1 (1992-1997), period 2 (1998-2003) and period 3 (2004-2009). Infants were compared based on their week of GA and by the study period in which they were born. Main Outcome Measures: GA, birthweight, incidence and severity of ROP. Results: Three hundred seventy-three (67.3%) infants survived until ROP screening, and 351 (63.4%) survived until discharge. ROP incidence increased from 78.2% in period 1 to 86.1% in period 3. Over the entire study, 90.5% of 23-week GA infants had ROP compared with 89.7% of 24-week GA infants and 76.1% of 25-week GA infants. Mean birthweight was significantly lower in infants with any ROP (725.1g) and ROP of at least stage 3 (720.8g) compared with infants without ROP (806.5g) (