Progression and timing of treatment of zone I retinopathy of prematurity

PURPOSE: To clarify the progression of zone I retinopathy of prematurity (ROP) and elucidate the most suitable time and method of treatment. " DESIGN: Interventional case series. METHODS: Forty-six eyes of 23 zone I ROP infants were studied at a single institution. Birth weight ranged from 448 to 954 g, and gestational age ranged from 22 to 26 weeks. Fundus examination was started at 29 or 30 weeks postmenstrual age and was performed once or more per week. The first treatment was performed using laser photocoagulation or cryotherapy when zone I ROP progressed to the following criteria. Treatment criteria A included 35 eyes of 18 cases of zone I any stage ROP with plus disease (Early Treatment for Retinopathy of Prematurity [ETROP] type 1), criteria B included five eyes of three cases of zone I stage 3 ROP with or without plus disease (ETROP type 1), criteria C included six eyes of four cases of stage I or stage 2 ROP without plus disease; the demarcation lines belonged, in large part,,vithin the zone I area. RESULTS: Hazy media such as corneal opacity, miotic pupil, tunica vasculosa lentis, and hazy vitreous persisted until approximately 32 weeks postmenstrual age. The mean period between stage I and stage 3 mild was one week, that between stage I and stage 3 moderate was 1.7 weeks, and that between stage I and stage 3 severe was 1.3 weeks. The period between stage I and the first treatment was zero to 2days, and 60.9% of all the cases were treated within 1days after stage 1. Six of 46 eyes bad unfavorable outcomes. Surgical results of our treatment were comparable or better than those of other reports. CONCLUSIONS: Immediate treatment was required when zone I ROP was diagnosed behind persistent hazy media.