[Optimum timing of initial examination for retinopathy of prematurity].

Objective: To determine when to begin examination for retinopathy of prematurity (ROP).
Methods: We retrospectively reviewed the medical records of 663 infants with birth weights of less than 1,500 g in Tokyo Metropolitan Bokutoh Hospital between June 1999 and March 2009, and investigated the timing of onset and initial treatment. In addition, we investigated visibility of fundus for infants of less than 27 weeks gestational age (GA).
Results: The mean GA was 28.7 weeks and the mean birth weight was 1,032.6 g. For infants of less than 27 weeks GA, the earliest onset was 29 weeks postmenstrual age (PMA) and the earliest initial treatment was performed at 30 weeks 0 days PMA. Regarding the visibility of the fundus, zone I could be seen for 50.8% of those infants receiving examination during the latter half of 29 weeks PMA and 71.7% of those infants receiving examination during the former half of 30 weeks. For the infants of a GA of 27 weeks or more, the earliest onset was 2 weeks chronologic age (CA) and the earliest initial treatment was performed at 3 weeks 3 days CA.
Conclusions: The optimum timing of initial examination for ROP proved to be between the latter half of 29 weeks and 30 weeks 0 days PMA for infants of a GA of less than 27 weeks; and 3 weeks CA for the infants of a GA of 27 weeks or more.