The factor of time in retinopathy of prematurity

PurposeTo analyze and discuss the relationship between the factor of time and our understanding of retinopathy of prematurity (ROP).MethodsThe author calls upon 30 years of experience in clinical investigations of ROP to critically synthesize selected literature on ROP, with attention to the broad theme of time. Future opportunities for clinical research are also considered.ResultsAlthough retinopathy of prematurity (ROP) ultimately is self-limited in its course, it is highly variable in its severity and outcome. Both the CRYO-ROP and the ETROP studies paid close attention to the chronology of ROP events; however, they approached the question of when to randomize eyes for treatment not simply according to a time definition, but rather according to disease severity characteristics. Still, results of both these studies can be reviewed from a time perspective, and indeed the pace of progression was one of the risk variables considered for ETROP randomization. The optimal schedule under which to perform eye examinations for active ROP is changing, as our understanding of this disease continues to improve.DiscussionThe factor of time is interwoven throughout the clinical course of ROP. Randomized clinical trials have proven to be an extremely efficient scientific method of comparing alternative treatment strategies. In looking toward the future, further randomized clinical trials are needed to investigate rational clinical management of cases in which retinal ablative therapy fails to arrest ROP’s progression.