144 Copyright © 2015 by the University Clinical Centre Tuzla, Tuzla, Bosnia and Herzegovina. ¹Department of Pediatrics, University Hospital Clinical Centre, Banja Luka Bosnia and Herzegovina, 2 Department of Ophthalmology, University Hospital Clinical Centre, Banja Luka, Bosnia and Herzegovina, 3 University Children's Hospital, Belgrade, Serbia, 4 Medical Faculty of Belgrade University, Belgrade, Serbia *Corresponding author: dragajojic@gmail.com Tel.: + 387 51 342 408 Fax.: + 387 51 342 463 Received: July 17, 2015 Accepted: August 14, 2015 Key words: Retinopathy of prematurity ■ Oxygen therapy ■ Risk factors ■ Premature infant. THE EFFECT OF OXYGEN THERAPY ON THE DEVELOPMENT OF RETINOPATHY OF PREMATURITY Dragica JOJIĆ 1* , Jelica PREDOJEVIĆ-SAMARDŽIĆ 1 , Milka MAVIJA 2 , Dimitrije NIKOLIĆ 3 , Vesna MARINKOVIĆ 4 Paediatrics Today 2015;11(2):144-153 DOI 10.5457/p2005-114.120 Objective – Te aim of this study is to show the efect of oxygen therapy in premature babies on the development of severe ROP. Ma- terials and methods – Tis retrospective research covered a period of two years, and included 108 premature babies, with birth weight <1500 g and gestational age <33 weeks, at the Children’s Ward of the University Hospital Clinical Centre, Banja Luka. Te efects of the length of oxygen therapy and episodes of hypoxia and hyperoxia on the development of severe ROP were analysed. Results – ROP was present in 64 (59.2%) newborns, of which 21 (19.4%) had severe ROP. Te incidence of severe ROP is statistically higher with lower birth weight, <1150 g (p<0.01), lower gestational age <30 weeks, longer oxygen therapy and when there were frequent episodes of hy- peroxia and hypoxia. By multiple logistic regression analysis, a very strong connection was established between severe ROP and exposure to episodes of hyperoxia (OR 32.73; CI 4.14-255.37), episodes of hypoxia (OR 14.08; CI 3.81-51.94), and oxygen therapy longer than 10 days (OR 15.54; CI 1.99-120.79). For most risk factors tested, there was a strong connection between severe ROP and birth weight <1250 g, gestational age <30 weeks, respiratory distress syndrome and perinatal asphyxia. Conclusion – Long-term oxygen therapy, prema- turity and low birth weight with hypoxia are important factors in the development of severe ROP. Constant education is necessary of staf regarding the potentially harmful efects of oxygen in order to prevent both hypoxia and hyperoxia. Introduction Retinopathy of prematurity (ROP) is an ill- ness of the immature retina, which causes se- vere damage to sight in babies with low ges- tational age and low birth weight. Several risk factors are responsible for the development of retinopathy of prematurity, which prevent the normal development of vascularization of the retina. One of the most important is the efect of oxygen therapy in premature babies with low gestational age (1). Oxygen was frst used in newborns who did not breathe spontaneously by Chaussier in 1780. Te use of oxygen in neonatology has been routine since the 1950’s, but it was quickly suspected that there was a connec- tion between the use of oxygen and the oc- currence of retinopathy of prematurity (2). Original article