Retinopathy of prematurity: optimal timing of the initial check and progression after discharge.

Timely detection of the threshold retinopathy of prematurity (ROP) is very important. The goal of this study was to discuss the optimal timing of the initial screening for ROP as well as ROP progression in the outpatient department (OPD) follow-up after discharge. Herein we retrospectively review the charts of 224 preterm babies with gestational ages (GAs) of less than 35 weeks or birth weights (BWs) of less than or equal to 2000 g. These babies were admitted to Taipei Veterans General Hospital from January 1998 to December 2000. The relationship between the severity and the time course of ROP with respect to various BWs was recorded. These infants were also divided into groups according to the ROP stage of the last retinal examination before discharge, and the recorded results of OPD follow-up. In this study, there was a total of 41 infants with stage III ROP, of which 36 progressed to threshold ROP, including 13 (13/41, 31.7%) and 10 (10/36, 27.8%) who were respectively detected after discharge. In 89 infants with positive findings, the postnatal age (PNA) at the time ROP was detected for the first time was about 7 weeks in extremely low birth weight (ELBW, BW < or = 1000 g) infants and about 4-5 weeks in larger infants; however the postconceptional age (PCA) was about 35 to 36 weeks, and this was not influenced by birth weight. The earliest PCA and PNA when infants with a BW of < or = 1,000 g or GA < or = 28 weeks reached the threshold ROP were 33 and 7 weeks; infants with a BW of 1,001-1,250 g or GA of 28-30 weeks, the times were 34 and 6 weeks; and for infants with a BW of > 1,250 g or GA of more than 30 weeks, they were 35 and 4 weeks, respectively. Although it seemed that ROP tended to develop at the same PCA, the dual criteria of 4 weeks of PNA or 33 weeks of PCA, whichever comes later, may be the optimal timing for the initial retinal examination for premature infants. It is also important to keep in mind that follow-up programs should not be interrupted because of discharge.