Cerebral and Mesenteric Perfusion Changes Due to Mydriatic Use for Retinopathy of Prematurity by Near-Infrared Spectroscopy

Aim: Retinopathy of prematurity (ROP) screening requires pharmacologic pupil dilation, which may be associated with systemic side effects in preterm infants.This study aimed to evaluate the impact of low-dose mydriatic eye drops on cerebral and mesenteric tissue oxygenation using near-infrared spectroscopy (NIRS). Materials and Methods:In this single-center prospective observational study, 30 preterm infants gestational age 32 weeks and/or birth weight 1,500 g) underwent 61 ROP examinations.A low-dose mydriatic protocol (0.625% phenylephrine and 0.25% tropicamide) was administered in two cycles.Regional oxygen saturation (rSO 2 ) was measured at multiple time points (from 15 minutes before to 48 hours after administration) at three sites: (rSO 2 -cerebral right), (rSO 2 -cerebral left), and mesenteric (rSO 2 -M).Splanchnic-cerebral oxygenation ratios (SCOR-R and SCOR-L) were calculated.Clinical complications were recorded.Results: Complications occurred in 13% of examinations, including apnea (6.5%) and feeding intolerance (9.8%), predominantly in infants with lower gestational age and primarily after the first examination.Overall temporal changes in NIRS parameters were minimal.However, in infants who developed complications, rSO 2 -M and SCOR-R values were significantly lower during the first examination compared to the second (p=0.043 and p=0.044, respectively).rSO 2 -M values below 70% and SCOR below 0.75 were noted within the first 6 hours post-medication, followed by recovery within 36-48 hours. Conclusion:Low-dose mydriatic regimens appear to be safe in preterm infants, with minimal disturbances in cerebral and mesenteric oxygenation.Transient reductions in mesenteric perfusion parameters may help identify those infants at risk of gastrointestinal intolerance, supporting delayed refeeding after ROP screening.These findings support the use of NIRS for monitoring post-mydriatic effects and may contribute to safer ROP screening protocols in premature infants.