Retinopathy of prematurity (ROP) is a physiopathological condition that develops upon abnormal proliferation of the retinal veins in neonates, and its pathogenesis is unknown.1 With the advancements in neonate care, the survival rate of premature babies with extremely low gestational ages and birth weights has increased significantly; however, this has also resulted in an increasing incidence of ROP, which may lead to vision defects and/or blindness. Early diagnosis, and timely and effective treatment may prevent vision loss and thus improve the developmental process and the quality of life of these infants. Therefore, recurring screening with retinal examination is essential to identify neonates who need ROP treatment.2, 3 The American Academy of Pediatrics and American Academy of Ophthalmology recommend ROP screening for preterm infants with a birth weight of ≤1500 g or a gestational age of ≤30 weeks, and selected infants with a birth weight between 1500 and 2000 g or a gestational age of \>30 weeks who have received cardiopulmonary supportive therapy, or who are considered by the attending clinician to be at risk for the development of ROP.4 The ophthalmological examinations for screening ROP involve repeated use of mydriatic eye drops, physical constriction, forced opening of the eyelids, insertion of the blepharostat, scleral indentation, and dense light, all of which cause pain and stress to the infant.5, 6 The extreme and long-term unreduced pain resulting from the interventions applied in the neonatal intensive care units (NICU) may generally cause life-threatening effects in organs and systems. Inadequate management of pain in preterm neonates can cause physiological changes and may also obscure the behavior of the infant, interactions between the family and the infant, and the adaptation of the infant to the social world, causing neurological and behavioral disorders and negatively affecting growth.7, 8, 9, 10 Thus, determination of optimal strategies for stress reduction and pain management related to these medical procedures is important in order to minimize the discomfort experienced by these neonates.

In order to reduce the pain and stress related to ROP examination, non-pharmacological methods, including the use of pacifiers, skin-to-skin touch, swaddling, kangaroo care, positioning, musical therapy, breast milk and breast feeding, single or recurring doses of oral sucrose, and personalized developmental care applications, have been used.5, 11, 12, 13, 14 However, a recent meta-analysis of randomized controlled studies evaluated a variety of non-pharmacological pain-reducing interventions in addition to topical ophthalmic anesthetics for ROP examination. Although multisensory pain treatments (e.g., oral dextrose/sucrose solution, breast milk, swinging, singing, non-feeding suction, swaddling) may reduce the pain to varying degrees, no specific treatment has been reported to show significant pain-relief ability. The Premature Infant Pain Profile (PIPP) score in most of the studies was \>12.11 Pharmacological methods are used for pain relief as well as non-pharmacological in neonates. The pharmacological agents include local anesthetics, non-steroidal anti-inflammatory drugs (NSAIDs), and opioid medications.15 Although topical anesthetics are routinely used in ROP examination in the NICU, they do not offer complete relief from pain.12 Moreover, opioid analgesics should be used carefully, due to their adverse effects such as respiratory depression, apnea, bradycardia, hypotension, intestinal hypoperistalsis, and bladder dysfunction. 16 NSAIDs are commonly used in newborns and children as antipyretic agents to control fever and as analgesic, anti-inflammatory, and vasoactive agents to manage pain and modulate inflammation.17 Paracetamol shows analgesic and antipyretic effects by inhibiting the cyclooxygenase (COX)-2 enzyme.17 It can be used safely in neonates during mild to moderately painful procedures and in the postoperative period. Malnory et al. showed that the preoperative use of paracetamol during circumcision of late preterm and term infants reduced pain within the first 24 h.18 Ceelie et al. reported that the intravenous use of paracetamol in neonates and infants after major surgeries reduced the need for morphine in the first 48 h following surgery.19 Ibuprofen, another NSAID, inhibits COX-1 and COX-2 enzymes to show analgesic, antipyretic, and anti-inflammatory effects.17 However, the role of ibuprofen in reducing pain in neonates has not been studied in detail. Recently, these two medications are commonly used in NICUs for ductus closure.20 To our knowledge, no previous study has compared the pain-reducing effect of ibuprofen and paracetamol in preterm infants during ROP examinations. Thus, this study aimed to compare the pain-reducing effects of single-dose ibuprofen and paracetamol in preterm infants during ROP examination by using the Neonatal Pain, Agitation, and Sedation (N-PASS) scale.