title: Progression and timing of treatment of zone I retinopathy of prematurity.
abstract: OBJECTIVE
  To clarify the progression of zone I retinopathy of prematurity (ROP) and elucidate the most suitable time and method of treatment.
  
  
  METHODS
  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 1 or stage 2 ROP without plus disease; the demarcation lines belonged, in large part, within 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 1 and stage 3 mild was one week, that between stage 1 and stage 3 moderate was 1.7 weeks, and that between stage 1 and stage 3 severe was 1.3 weeks. The period between stage 1 and the first treatment was zero to 20 days, and 60.9% of all the cases were treated within 10 days after stage 1. Six of 46 eyes had 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.
authors.affiliation: Eye Department, Osaka Medical Center and Research Institute for Maternal and Child Health, 840 Murodo-cho, Izumi, Osaka, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Soh
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujino
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Hatsukawa
mesh_terms: D003318:Corneal Opacity / Q000503:physiopathology; D017679:Cryotherapy; D018450:Disease Progression; D005260:Female; D005865:Gestational Age; D006801:Humans; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D017075:Laser Coagulation; D008297:Male; D011681:Pupil Disorders / Q000503:physiopathology; D012178:Retinopathy of Prematurity / Q000503:physiopathology* / Q000601:surgery*; D012591:Scleral Buckling; D013997:Time Factors; D014821:Vitrectomy; D014822:Vitreous Body / Q000503:physiopathology