Citation
Zhou Yifan, Rong Hua, Li Zhiqing, et al. Comparison of the effects of two different concentrations of mydriatic drugs in Chinese type 2 diabetic patients: a randomized controlled trial[J]. Chin J Exp Ophthalmol, 2025, 43(8):739-744. DOI: 10.3760/cma.j.cn115989-20241226-00365.
ABSTRACT [Download PDF] [View Full Text]
Objective To compare the mydriatic effects of a combination of 1% tropicamide and 2.5% phenylephrine with a 0.5% tropicamide and 0.5% phenylephrine combination in patients with type 2 diabetes.
Methods A randomized, double-blind, controlled trial was conducted.Ninety Chinese patients (90 eyes) with dark irises and type 2 diabetes who needed mydriasis examination at the Fundus Disease Clinic of Tianjin Medical University Eye Hospital from June to September 2024 were included.The subjects were divided into control group (30 patients 30 eyes), high concentration group (30 patients 30 eyes) and half-dilution group (30 patients 30 eyes) using the random number table method, which received 2 drops of a mixture of 0.5% tropicamide and 0.5% phenylephrine, 2 drops of a mixture of 1% tropicamide and 2.5% phenylephrine, 1 drop of a mixture of 1% tropicamide and 2.5% phenylephrine+ 1 drop of saline respectively.The pupil diameter of the patients was measured with a pupillometer 40 minutes before and after instillation.The study adhered to the Declaration of Helsinki and the study protocol was approved by the Ethics Committee of Tianjin Medical University Eye Hospital (No.2024KY-16).Written informed consent was obtained from all participants.
Results The proportions of patients whose pupil diameters reached 7 mm 40 minutes after the initial administration in the control group, high-concentration group, and half-dilution group were 56.7%(17/30), 86.7%(26/30) and 66.7%(20/30), respectively, with a statistically significant overall difference ( χ 2=6.667, P=0.036).The proportion of patients in the high-concentration group whose pupil diameter reached 7 mm 40 minutes after the initial administration was higher than that in the control group, and the difference was statistically significant ( P<0.05).The pupil diameters 40 minutes after the initial administration in the control group, the high-concentration group and the half-dilution group were (7.01±0.86), (7.64±0.61) and (7.49±1.15)mm, respectively, with a statistically significant overall difference ( F=4.019, P=0.021), and the pupil diameter of the high-concentration group was significantly higher than that of the control group ( P=0.024).Changes in pupil diameter 40 minutes after the initial administration in the control group, high-concentration group and half-dilution group were (3.23±0.81), (3.82±0.60) and (3.62±0.75)mm, respectively, with a statistically significant overall difference ( F=5.121, P=0.008), and the change in pupil diameter in the high-concentration group was higher than that in the control group ( P=0.007).
Conclusions The combination of 1% tropicamide and 2.5% phenylephrine has better pupil dilation than the combination of 0.5% tropicamide and 0.5% phenylephrine.It is recommended that pupil dilation be performed with a high-concentration mydriatic drug prior to outpatient fundus examination for diabetic patients.