Histopathologic study on endoscopic cyclophotocoagulation and trans-scleral cyclophotocoagulation in rabbit eyes / 眼科研究

ABSTRACT

Background Endoscopic cyclophotocoagulation(ECP) is a new approach to treat refractory glaucoma.But,the histopathological change of ciliary body after ECP has not been reported yet.ObjectivePurpose of the present study is to explore the histopathologic change of ciliary body after ECP and investigate the mechanism of lowing intraocular pressure(IOP) of ECP and compared with trans-scleral cyclophotocoagulation (TSCP).MethodECP was performed on the right eyes of 30 adult pigmented rabbits and TSCP was taken in the fellow eyes.Other two normal pigmented rabbits were as control group.The clinical examinations were performed in day 1,3,5,7,14,28,42 and 56 after operation under the slim lamp to evaluate the inflammatory reactions of conjunctiva,sclera and cornea,and the IOP was detected in the same time points.The animals were sacrificed and the eyeballs were extracted for the examination of structure of ciliary body under the light microscope in day 7,14,28,42 and 56 after surgery respectively.ResultsThe mild inflammatory response and local opacity of lens were seen under the slim lamp in the eyes after ECP,and severe inflammatory reaction was in the eyes received TSCP.No opacity of lens was found after TSCP through the observing period.The lowing-IOP extent was significantly higher in ECP group than TSCP group after operation(P＜0.01).The structure of ciliary body epithelium was normal in normal rabbit eyes.The disruption of ciliary body epithelium,especially for non-pigment epithelial layer,edema of ciliary process were seen in the early period after ECP.Fourty-two days later,the irregulation of ciliary body epithelium and atrophy of ciliary process were exhibited under the light microscope.In TSCP group,the edema,blooding and damage of ciliary process were seen,but slight inflammatory response was in the ciliary epithelium.After 42 days of surgery,atrophy of ciliary body,irregular proliferation of pigmental and non-pigmental epithelial cells,thinness of sclera and scarring of ciliary stroma were revealed.ConclusionCompared with TSCP,ECP can selectively destroy ciliary epithelium effectively and thoroughly and therefore reduce IOP.The adverse effect of ECP is the opacity of lens.Less damage of adjacent tissue is found in ECP compared with TSCP.