Background: Preterm infants undergo serial eye examinations during their hospital stay to monitor for the development of a specific disease termed retinopathy of prematurity. While those examinations are known to cause significant pain and stress, the current standard of care (sucrose and local anesthesia) is not adequate in terms of alleviation of pain. Purpose: The goal of this clinical trial is to test the effectiveness of dexmedetomidine for pain management in preterm infants undergoing routine eye examinations. The main questions it aims to answer are: * Does dexmedetomidine reduce the pain scores of preterm infants during and shortly after eye assessments in comparison to placebo (saline 0.9%). * Does dexmedetomidine cause more adverse effects than placebo. In this crossover study participants will receive either dexmedetomidine or saline 0.9% intranasally 30 minutes before the examination, on top of the current standard of care. The participants will be monitored closely for 5 hours to note differences in adverse effects. The researchers will use video monitoring to assess the pain scores using a standardized and validated scoring system.