【摘要】  AIM: To explore the anatomical changes of the optic nerve head in cats after radial optic neurotomy（RON）.METHODS: The normal anatomic data were obtained from 12 healthy cats. A total of 18 healthy cats were used in the experiment, which were divided into four groups: each operative group was executed at the 1st, 15th, 30th, 90th day after undergoing RON unilaterally.(six in 1st group). The enucleated eyes of each operative group were cut section routinely and embedded in paraffin, the cross sections were stained by special staining. RESULTS: At the 1st day after operation, the incision came into being and connected with cerebral subarachnoid space of orbital optic nerve. At 15th day, incision was fusiform and hyperplastic neuroglial cells and fibroblasts aggregated at the incision. At 30th day, there was obvious proliferation of type fibril at the neurotomy. The aligned texture of collagen fibril of the lamina cribrosa near the incision was moved close to each other. At the 90th day, a discrete scar was noted at the site which reached the cribriform and sclera. CONCLUSION: RON can cut scleral ring and piamater of optic nerve sharply. The incision of RON connects with subarachnoid space of orbital optic nerve and becomes broaden gradually at the site of scleral ring. The potential role of incision of RON is relevant to the subject.

【关键词】  ptic nerve optic disc; cat central retinal vein occlusion

    INTRODUCTION

    Central retinal vein occlusion (CRVO) can result in loss of vision from intraretinal hemorrhage, edema, or retinal ischemia. Recently, Opremcak[1-3] has advocated the use of a radial optic neurotomy (RON) as a possible treatment of CRVO. Others have followed with similar case series. Opremcak concludes that radial optic neurotomy may improve visual acuity in eyes with CRVO, and it has initially proved to be safe, although further studies must be performed to address potential serous complications such as damage to the central retinal artery and vein. Hayreh believes that the procedure is useless and even possibly dangerous for several anatomic reasons[4].

    We choose the cats as the experimental model because the lamina cribrosa of cats are well developed. The histological studies of the cats have been proved that the lamina bundles of cat contain all the three kinds of fibers of human. The three dimensional structure of collagenous fibers of cat is similar with human.  The ratio of dimension is close to that of humanity[5] . Our objective is to perform a RON in cats and to examine histological changes of the optic nerve head and lamina cribrosa.

    MATERIAL AND METHODS

    Material  A total of 12 healthy cats 24 eyes were used in the experiment, the normal anatomic data of the distance between limbus and pars plana, thickness of eyeball wall at the site of perioptic nerve and the diameter of optic nerve head were measured of all normal eyes. A total of 18 healthy cats were used in the experiment, which were divided into four operative groups. Four operative groups were executed at the 1st, 15th, 30th, and 90th day after undergoing RON bilaterally (Six in 1st group). The enucleated eyes of each operative group were divided into two parts: one part was cut section routinely and enbedded in paraffin, the cross sections were stained by hematoxylin-eosin（HE）staining and picrosirus red staining.

    Methods  Animals were underwent local drops with 0.1mL of 10g/L atropine sulfate and then were anesthetized with 10 to 40mg/kg of intramuscularly ketamine hydrochloride. All animals were initially examined with indirect ophthalmoscopy to exclude any preexisiting vitreoretinal abnormalities. The 20-gauge MVR blade was used to perform a radial incision at the edge of the optic nerve head on both eyes of each animal. The sclerotomies and conjunctiva were sutured with 6-0 polyglactin and absorbable suture respectively. Twenty milligram gentamicin sulfate was injected into the subconjunctival space.

[1] [2] [3] [4] 下一页