Objective:To evaluate the effect of short-term topical administration of atropine eye drops with various concentrations and frequencies on eye safety in children.Methods:A double-blind randomized controlled trial was conducted.Sevevty-two children with ametropia or pre-myopia (72 eyes) were enrolled in Tianjin Medical University Eye Hospital from December 2020 to January 2022.The subjects were randomly divided into 0.01% atropine group, 0.02% atropine group and 0.04% atropine group according to a random number table, with 24 cases (24 eyes) in each group.Automatic refraction with an automatic computer optometry device, subjective refraction with a phoropter, intraocular pressure with a non-contact tonometer, axial length by optical biometrics, the amplitude of accommodation (AMP) by the push-up method, pupil diameter with pupilometer, near visual acuity at 33 cm with a standard logarithmic visual acuity chart, tear evaluation with Keratograph 5M and Ocular Surface Disease Index (OSDI) questionnaire survey were performed among all subjects.One drop of 0.01%, 0.02%, and 0.04% atropine was administrated to the study eye according to grouping, and the pupil diameter was measured every 10 minutes until the pupil did not enlarge three times, then the data after a single treatment of the three groups were recorded.After one-week application of the corresponding concentration of atropine eye drops once at night, the data after one-week treatment were recorded.For the next week, the application frequency of 0.01% and 0.02% atropine groups changed to once daily in the morning and evening, and 0.04% atropine group maintained once at night, then the data after two-week treatment were recorded.Data of the right eyes were analyzed.The changes in pupil diameter, AMP and other eye parameters before and after atropine eye drops of the three groups were compared.This study adhered to the Declaration of Helsinki and the study protocol was approved by the Ethics Committee of Tianjin Medical University Eye Hospital (No.2020KY[L]-51). All subjects and their guardians were fully informed of the method and purpose of this study before entering the cohort.Written informed consent was obtained from guardians.Results:Pupil diameters of 0.01%, 0.02% and 0.04% atropine groups were (5.59±0.48), (5.35±0.76) and (5.65±0.43)mm before treatment respectively, (7.00±0.68), (7.17±0.58) and (8.40±1.71)mm after a single treatment, (6.67±0.62), (6.56±0.65) and (7.60±0.69)mm after one-week treatment, (6.96±0.49), (7.04±0.53) and (7.60±0.36)mm after two-week treatment.There were significant differences in pupil diameter at different time points after treatment among the three groups ( Fgroup=9.430, P<0.001; Ftime=156.620, P<0.001). The AMP of 0.01%, 0.02% and 0.04% atropine groups were (12.94±3.02), (13.25±2.81) and (13.42±2.60)D before treatment respectively, (11.62±2.61), (11.53±2.06) and (9.64±1.93)D after a single treatment, (11.14±2.61), (11.33±2.33) and (8.30±1.18)D after one-week treatment, (9.99±1.81), (8.72±1.25) and (8.76±2.12)D after two-week treatment.There was no significant difference in the AMP among the three groups ( Fgroup=2.800, P=0.063). In the three groups, the AMP at different time points after treatment were significantly lower than that before treatment ( Ftime=61.400, P<0.001). There was no difference in spherical equivalent refraction, intraocular pressure, near visual acuity, axial length, first none-invasive tear break-up time, average none-invasive tear break-up time, tear meniscus height and OSDI score among the three groups ( Fgroup=0.030, 0.630, 1.420, 0.580, 0.140, 0.120, 0.340, 0.142; all at P>0.05). There were significant differences in spherical equivalent refraction, intraocular pressure, first none-invasive tear break-up time, average none-invasive tear break-up time, tear meniscus height and OSDI score at different time points between before and after medication among the three groups ( Ftime=12.560, 4.730, 4.720, 5.220, 3.720; all at P<0.05). Conclusions:Varying pupil dilation and AMP reduction occur after the use of different concentrations of atropine and are more severe at higher concentrations.Increased administration frequency of atropine is associated with more pupil dilation and AMP reduction, but there is no intolerable adverse effect.