Abstract
Purpose: :
Recently, improved neonatal care has resulted in an increased survival of extremely immature infants born at 22-27 gestational weeks. The general aim of this national project was to evaluate mortality and morbidity in this group of infants. The aim of the present ophthalmological study was to investigate various aspects on ROP in this population.
Methods: :
A national prospective study on infants born before 27 weeks of gestation in Sweden during 2004 to 2007 has been performed. Screening for retinopathy of prematurity (ROP) was performed weekly or every second week from the 5th postnatal week.
Results: :
Of 707 live born infants, the present study group comprises 506 infants surviving for at least 35 days. Of those, 368 (73%) infants developed ROP; 38% mild ROP and 35% severe ROP. Four infants developed Aggressive Posterior ROP (AP-ROP). Treatment was performed in 20%. Incidence and severity of ROP was significantly associated with gestational age (GA) (weeks) at birth (p<0.001).There was a high correlation regarding stage of ROP in the right and left eyes (p<10-6). Age at onset of ROP varied from 29.9 to 41.7 weeks of postmenstrual age (PMA). A linear regression analysis revealed a significantly earlier PMA at onset of ROP in the most immature infants (p<10-6)
Conclusions: :
This national population-based study reveals a high risk of ROP in infants born at 22-27 weeks gestation, higher than previously reported. The high survival rate of extremely preterm infants, even when including infants at the limits of viability, the possibility to track infants with personal identification numbers and the ophthalmological, prospective design of the study, may all contribute to this finding.
Keywords: retinopathy of prematurity • retinal development • clinical (human) or epidemiologic studies: natural history