Abstract
Purpose: :
Recent studies from developing countries have reported severe retinopathy of prematurity (ROP) occurring in higher birth weight premature infants. Centers in India, China, and Peru are reporting mean gestational ages at birth of 30 weeks or higher for children requiring treatment in contrast to 26 weeks or less in the United States. To better understand the reasons for this discrepancy, we have evaluated neonatal clinical practice patterns as well as clinical exams from the Aravind Eye Institute in India of children who went on to develop severe posterior ROP requiring treatment.
Methods: :
A retrospective study was performed on preterm infants from two neonatal intensive care units (NICUs) born between July 2002 and November 2003 and who were screened for ROP. The American and British were applied to our cohort and evaluated in terms of sensitivity. Photodocumentation was performed using digital fundus photography, and in cases requiring treatment, fluorescein angiography was performed.
Results: :
Of the 166 infants screened 54 (33%) cases had severe ROP requiring treatment, of which 36 had zone 1 aggressive posterior ROP (AP-ROP). The mean gestational age of children with severe ROP was 31.37 weeks (range 28-34 weeks) and the mean birth weight was 1471 g (range 850-2290 g). Of the 61 patients who had an eye exam in the NICU prior to discharge, 41 (67%) had loss of vascularized retina based on zone when examined as an outpatient, and 10 had contraction from Zone 3 to Zone 1. Fundus photography showed that a majority of children had posterior Zone 1 disease with Plus disease but no evidence of stage 3. Fluorescein angiography revealed large geographic areas of vaso-obliteration (up to 30 disc areas) posterior to the shunt within otherwise vascularized retina. Children typically received supplemental oxygen via a non-re-breather funnel mask resulting in 70%-100% inspired oxygen ranging from 3 days and longer.
Conclusions: :
At this referral center, the high rate of retinopathy was associated with large areas of vaso-obliteration in vascularized retina in the setting of unregulated and prolonged oxygen use. The angiographic findings are consistent with vascular pattern seen in the animal model of oxygen induced retinopathy. Our results raise the possibility that oxygen may be an exacerbating factor in the development of ROP and that more stringent use of oxygen supplementation may reduce the severity of ROP in this patient population.
Keywords: retinopathy of prematurity • clinical (human) or epidemiologic studies: risk factor assessment • infant vision