title: Zone I retinopathy of prematurity: clinical characteristics and treatment outcomes.
abstract: OBJECTIVE
  To study the clinical characteristics and treatment outcomes after laser and surgical treatment in a series of infants with zone I retinopathy of prematurity (ROP).
  
  
  METHODS
  Preterm infants less than 1,500 g at birth diagnosed with zone I ROP were studied. Fifty-seven consecutive eyes in 29 infants with zone I ROP were treated with indirect diode laser. Within zone I, two anatomic subgroups (anterior and posterior) were defined. Additionally, 27 eyes (15 patients) with retinal detachment secondary to zone I ROP were surgically treated. Structural outcomes were evaluated 3 months after surgery.
  
  
  RESULTS
  Atypical morphologic characteristics were observed. Thirty-one out of 48 eyes (64.6%) with anterior zone I ROP and none of the 9 eyes with posterior zone I ROP had a favorable outcome (P < 0.001) after photocoagulation. In the surgery group, 14 out of 19 (74%) eyes with stage 4 and 1 out of 8 (13%) eyes with stage 5 had favorable outcomes.
  
  
  CONCLUSIONS
  Atypical clinical features can be observed in zone I ROP. A posterior localization of the disease carries a worse prognosis after laser photocoagulation. Surgical intervention can effectively reattach the retina in a significant number of zone I ROP-related retinal detachments.
authors.affiliation: Hospital de Niños Roberto del Río, Santiago, Chile. akychenthal@entelchile.net
authors.forename: Andres
authors.initials: A
authors.lastname: Kychenthal
authors.forename: Paola
authors.initials: P
authors.lastname: Dorta
authors.forename: Ximena
authors.initials: X
authors.lastname: Katz
mesh_terms: D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D017075:Laser Coagulation / Q000379:methods*; D011183:Postoperative Complications; D012163:Retinal Detachment / Q000473:pathology / Q000601:surgery; D015861:Retinal Neovascularization / Q000209:etiology / Q000473:pathology; D012178:Retinopathy of Prematurity / Q000473:pathology* / Q000601:surgery*; D012591:Scleral Buckling / Q000379:methods*; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014821:Vitrectomy / Q000379:methods*