Retinopathy of prematurity: a study of prevalence and risk factors.

BACKGROUND: Retinopathy of prematurity (ROP) is a serious complication of prematurity treatment and can lead to blindness unless recognized and treated early.

OBJECTIVE: The objective was to estimate the prevalence of ROP in preterm infants in the Neonatal Intensive Care Unit (NICU), to identify the risk factors which predispose to ROP, and to assess the outcome of these cases.

MATERIALS AND METHODS: A ROP prospective screening survey was performed enrolling all prematures admitted to the NICU from January 2009 to December 2010, with a gestational age of 32 weeks or less at birth and a birth weight of 1500 g or less. Infants whose gestational age was >32 weeks or birth weight was >1500 g were included if they were exposed to oxygen therapy for more than 7 days. A total of 172 infants (84 males and 88 females) had retinal evaluation by indirect ophthalmoscopy from the fourth postnatal week and followed up periodically. Perinatal risk factors for ROP were assessed using univariate and multivariate analysis. Infants who progressed to stage 3 ROP were given laser therapy.

RESULTS: Out of the studied 172 infants, 33 infants (19.2%) developed ROP in one or both eyes; 18 (54.5%) cases stage 1, 9 (27.3%) cases stage 2, and 6 (18.2%) cases stage 3. None of the studied neonates presented ROP at stages 4 or 5. The six cases diagnosed as ROP stage 3 underwent laser ablative therapy. Univariate analysis showed that there was a significant relationship between the occurrence of ROP and gestational age (P = 0.000), sepsis (P = 0.004), oxygen therapy (P = 0.018), and frequency of blood transfusions (P = 0.030). However, an insignificant relationship was found between the occurrence of ROP and sex, mode of delivery, birth weight, respiratory distress syndrome, patent ductus arteriosus, intraventricular hemorrhage, hypotension, phototherapy, duration of oxygen therapy, mechanical ventilation, and CPAP (all P > 0.05). Gestational age, sepsis, oxygen therapy, and frequency of blood transfusions remained significant variables after logistic regression analysis.

CONCLUSION: The prevalence of ROP in this study was 19.2%; low gestational age, sepsis, oxygen therapy, and frequent blood transfusions were significant risk factors for ROP. Laser was effective in treatment and decreasing the progression of ROP. As this is a unit-based study, a comprehensive countrywide survey on ROP in Egypt is recommended to determine any regional differences in disease prevalence.