Inhaled Nitrous Oxide for Pain Relief During Eye Exam in the Pre-term Infant

The primary objective of the proposed study is to show that inhaled equimolar mixture of oxygen and nitrous oxide (EMONO) will reduce pain associated with retinal exam in the preterm infant, as compared to the current standard treatment (oral sucrose and topical anaesthesia). The investigators also aim to show that EMONO can be used safely in preterm neonates undergoing retinal exam, and will not result in any increase in apnea, bradycardia, or desaturation in the 24 hours following the exam. Finally, the investigators aim to show that EMONO will keep the infant calm, and make retinal examination easier and less traumatic.