Zhonghua Yan Ke Za Zhi. 2026 May 11;62(5):346-352. doi: 10.3760/cma.j.cn112142-20250915-00381.
ABSTRACT
Objective: To evaluate the efficacy and safety of low-dose compound tropicamide eye drops for pupillary dilation in premature infants undergoing the fundus examination. Methods: A non-inferiority, randomized, controlled, crossover trial was conducted. Preterm infants hospitalized in the Department of Neonatology, the First Affiliated Hospital of Zhengzhou University scheduled for retinopathy of prematurity screening between October 2024 and June 2025 were enrolled. Participants were randomly assigned to group A or group B using simple randomization. Group A received standard-dose (90 μl) compound tropicamide eye drops in the first fundus examination, but low-dose (45 μl) drops in the second examination, whereas group B received the two doses in the reverse order. The primary efficacy outcomes were the pupil diameter measured 60 to 75 minutes after dilation and the difficulty of fundus examination as assessed by the ophthalmologist (classified as easy, difficult, or impossible). The difference in pupil diameter between the two groups and its 95% confidence interval (CI) were calculated and compared with the non-inferiority margin to determine non-inferiority. The safety was assessed based on changes in vital signs and adverse events. A linear mixed model and generalized estimating equations were used to compare differences between groups. Results: A total of 72 infants were enrolled. Group A comprised 34 infants, of whom one was lost to follow-up during the second examination; group B comprised 38 infants, of whom three were lost to follow-up during the second examination. In the two groups, the gestational ages at birth were (30.85±2.38) and (31.81±2.61) weeks, the birth weights were (1 262.06±422.56) and (1 357.63±389.31) g, and male infants accounted for 35.29% (12 cases) and 50.00% (19 cases), respectively. No statistically significant differences were observed in demographic characteristics or clinical complications between the two groups (all P>0.05). At 60 to 75 minutes after dilation, the difference in pupil diameter between the low-dose and standard-dose regimens was 0.24 mm (95% CI: 0.18 to 0.29), with the upper limit of the 95% CI falling below the pre-specified non-inferiority margin. The rate of examination difficulty was 3% (95% CI: 1% to 11%) after standard-dose administration and 7% (95% CI: 3% to 16%) after low-dose administration, with a rate difference of 4% (95% CI: -1% to 9%, P=0.087; after Bonferroni correction, P=0.435). The lower limit of the 95% CI was above -5%. After low-dose administration, the oxygen saturation by pulse oximetry was 0.09% lower (95% CI: -0.32 to 0.15, P=0.470; after Bonferroni correction, P=1.000), and the heart rate was 0.34 beats/min lower (95% CI: -1.11 to 0.43, P=0.381; after Bonferroni correction, P=1.000), compared with standard-dose administration, with no statistically significant differences. The systolic blood pressure was 0.45 mmHg (1 mmHg=0.133kPa)lower (95% CI: -0.86 to -0.05, P=0.028; after Bonferroni correction, P=0.140), and the diastolic blood pressure was 0.65 mmHg lower (95% CI: -1.05 to -0.25, P=0.001; after Bonferroni correction, P=0.005) after low-dose administration compared with standard-dose administration, with only the difference in diastolic blood pressure reaching statistical significance. Adverse events occurred 11 times after standard-dose administration and 3 times after low-dose administration. Conclusion: For fundus screening in preterm infants, low-dose (45 μl) compound tropicamide eye drops are non-inferior to the standard dose (90 μl) in terms of mydriatic efficacy, while offering advantages in safety profile.
PMID:42103666 | DOI:10.3760/cma.j.cn112142-20250915-00381
