| Objective:To investigate the effects of topical application of 1%atropine eye drops on ocular biological parameters of normal adult guinea pigs,record the changes of ocular structure and function,and observe whether there are side effects and adverse reactions.Materials and Methods:Ten 1 to 2-year-old guinea pigs were selected and given a drop of 1%atropine eye drops to the right eye(experimental eye)at a fixed time every day,while the left eye used artificial and served as the contralateral eye.Before treatment,and after one-,two-,three-,four-.Five-,six-week,using retinoscope and pupillometer to measure the spherical equivalent refraction(SER),pupil diameter,and the pupil response to light reflection.At the same time,spectral domain optical coherence tomography(SD-OCT)was performed to a acquire fundus images when animals were under anesthesia,collect the data of retinal thickness,choroidal thickness,cross-sectional area of blood vessels in the central third of choroid,and the total area of choroidal in the corresponding region,and then calculate the ratio of choroidal vascular area to total area.Results:Except one guinea pig died of acute gastric perforation,the other animals were in good condition during the whole experiment,and there were no mood swings and any adverse drug reactions related to atropine.After using the eye drops,there was no eye discomfort such as redness,photophobia,tears and frequent blinking.Before treatment,there were no significant differences between the right and left eyes in equivalent spherical degree,resting maximum pupil diameter,and minimum contracting pupil diameter after strong light stimulation.The hyperopia of the right eye increased significantly after six weeks of atropine treatment(P<0.001),and the difference was statistically significant compared with that of the left eye(P<0.001).In the right eye,atropine significantly increased the resting maximum and minimum contracting pupil diameters(P<0.001,P<0.001),but the left eye remained unchanged.There was no significant difference in choroidal thickness between the two eyes at baseline.During the experiment,the choroidal thickness of the right eye increased,and the difference between the two eyes(right eye-left eye)increased significantly(P=0.029).No significant difference in the central third of choroidal vessels area and retinal thickness was detected between the right eye and the left eye at each time point.Conclusion:Atropine has the effect of dilatation and ciliary paralysis in guinea pigs,as well as increase the choroidal thickness.Topical use of 1%atropine does not cause serious adverse reactions to the eyes of guinea pigs and can be safely used for subsequent basic research.Purpose:Topical atropine is now widely used by pediatric optometrists and ophthalmologists for controlling myopia progression;however,the optimal dosing routine is yet to be determined.This study compared the efficacy of topical 1%atropine applied daily versus every three day for controlling myopia in pigmented guinea pigs.Materials and Methods:To induce myopia pigmented guinea pigs(New Zealand strain,n=38)wore monocular-10 D custom-made rigid gas-permeable(RGP)contact lenses for three weeks,after which they were replaced with-15 D contact lenses for another three weeks.Twelve animals were also treated with daily 1%atropine(exp.group 1),eleven with atropine every three day(exp.group 2),and fifteen with topical artificial tears as a placebo control treatment(control group).SER and axial length(AL)data,as well as retinal and choroidal thickness data were collected at weekly intervals using retinoscopy,ocular biometry(Lenstar),and SD-OCT,respectively.Results:Topical 1%atropine significantly slowed down myopia progression.Mean(±SEM)interocular differences(treated-fellow)in SER at week-0(baseline)were similar for all groups,but significantly different by week-6(P<0.001).Interocular differences in AL at week-0 were also not significantly different,but were by week-6(P<0.001).For the control group,the interocular difference in choroidal thickness and blood vessel area decreased over the time as expected.These changes were attenuated by topical atropine.There is no significant difference in retinal thickness among the three groups,at any time.Conclusions:For the negative contact lens-induced pigmented guinea pig model,administration of 1%topical atropine daily or every three-day slowed myopia progression.Although further investigations are needed,these results challenge the need for daily dosing of atropine for myopia control. |
PDF Full Text Request