Effects Of Accommodation On The Uveoscleral Outflow Pathway And Intraocular Pressure

Objective:1.To observe the effect of accommodation on the uveoscleral outflow pathway through morphological observation.2.To investigate the effect of IOP of emmetropes and different types of myopia induced by accommodation.3.To compare the influences of static and repeated accommodation on the intraocular pressure.Methods:1.Fourteen rabbits were treated with pilocarpine eye drops and atropine eye gelatin which simulated accommodation and non-accommodation states.Immunofluorescence was detected by instillation of FITC-BSA into anterior chamber after 30 mins,at 0.5,1.5,2.5,3.5 and 4.5 hours.After giving the anterior chamber injection 2 rabbits were killed and frozen section of the eyes were taken on which the fluorescence intensity and distribution patterns of uveoscleral outflow pathway were detected respectively.4 rabbits were killed after drug-treated for 30 mins then the eye-balls taken from these rabbits were fixed using which the pathological specimens were prepared with hematoxylin-eosin(HE)staining and smooth muscle antibody(SMA)immunohistochemical staining.The morphology of ciliary smooth muscle and intracellular space were observed with optical microscope.2.Eighty-eight volunteers participated in this study:28 emmetropes and 60 myopes.The myopes were divided into two groups according to refractive stability:stable myopes and progressing myopes.Meanwhile,myopes were also divided into three groups according to the degree of myopia:low myopes,moderate myopes and high myopes.All subjects had their IOPs measured using the rebound tonometer while accommodative stimuli of 0D and 3D were presented.Statistical analysis was performed on intraocular pressure before and after accommodation.3.A total of 45 volunteers were included in the study.Patients were randomly divided into group A(22)and group B(23).Group A had their IOPs measured using the rebound tonometer while accommodative stimuli of 0D,2D and 4D static accommodation were presented.Group B had their IOPs measured using the rebound tonometer while accommodative stimuli of 0D,2D and 4D repeated accommodation were presented.Statistical analysis was performed on IOPs and after accommodation.Results:1.The outcome of IOPs showed a statistical decrease in the accommodation group(P < 0.05).Compared with the non-accommodation group,the fluorescence intensity of ciliary body(P<0.05),suprachoroidal and anterior scleral of the accommodation group were stronger(P>0.05).Light microscopy observation showed that the ciliary radial muscle space was obvious in non-accommodation group,however,we did not find this space in accommotion group.2.There was no significant difference in IOPs among groups when no accommodation was induced(P> 0.05).The IOPs of progressing myop es and high myopes were significantly increased with 3D accommodation(P<0.05).However,the IOPs experienced an insignificantly slight decrease after 3D accommodation in stable myopes,low myopes,and moderate myo pes decreased was not obvious(P> 0.05).3.The IOPs of Group A was not significantly decreased after accommodation(P> 0.05),but the IOPs of Group B was significantly decreased after accommodation(P<0.01).In different degrees(2D,4D)of accommodation,the IOPs in Group B decreased more than group A(P<0.05,P <0.01).Conclusions:1.In the non-accommodation state,the radial ciliary muscle showed obvious muscle interspaces.The ciliary interspace was disappeared after accommodation,thereby reducing the uveoscleral outflow.2.Accommodation could increase the IOPs of progressing myopes and high myopes,and it suggested that the increase of IOP was related to the progression of adult myopia.3.The IOPs was significantly reduced after repeated accommodation,and aqueous humor outflow is relatively affected by frequent ciliary muscle contractions.