An Experimental Study To The Effect Of Silicone Oil On The Endothelium Corneal

Vitrectomy has been used widely since the 1970,s as anew kind of operation. Now it is a main method of treatmentfor the complicated retinal detachment. It is ordinary thatsilicone oil is used to put into the eye during the operation.However, the keratopathy is a serious complication aftervitrectomy, which is caused by silicone oil into the anteriorchamber, so that the patients with the success of vitrectomywill lose the opportunity to regain the visual function. Todaythere are some achievements of study on keratopathycaused by silicone oil in the world, but until now the exacttime that silicone oil can be kept in the antier chamberwithout keratopathy is unknown, so we are sure that theresearch will offer the reference and help for the clinicalwork .In the research we are going to take the animalexperiment to study the effect of silicone oil on endotheliumcorneal, and expect to obtain the accurate time that siliconeoil can be kept in the anterior chamber without keratopathy.At the same time, we want to find an effective method oftreatment for the complication, and we will provide thereasonable theory basis and help for clinical work, after allthe complication often happens after vitrecomy withaphakia. At first, we put silicon oil into the anterior chamber ofrabbit's eyes(the group can be called SI briefly). The resultof study shows: the slight keratpathy is found by theslit-lamp after 4 weeks and 8 weeks, and the keratpathy ismore serious after 12 weeks. The endothelium cornealdecreases obviously by endothelial cell count instrument.The results of histology and electromicroscopy show: thecore of cells shrinks, link of cell is loose. Many layers ofendothelium corneal have been made gradually, crude fiberof endothelium corneal should increase by degrees.Endothelium corneal cells disintegrate and disappearpartly, bottom membrane is exposed little by little. Corneaof the group is edematous by the slit-lamp which silicone oilis put in and taken out of the anterior chamber (the groupcan be called SIO briefly). Compared with the group SI, thecorneal thickness of the group SIO all increases lightly(P<0.01). Silicone oil comes into the anterior chamber and keepclose to the endothelium corneal, which will cause two kindsof diseases: one is decompensation, that is to say, the corneais edema and opacity, the other is corneal degeneration.Norman .BC,s research shows: silicone oil can likelydissolve such as cholesterol and other lipophiliccompounds out of the membranes. Another possibility isthat the change compared with that between aqueoushumor and the cornea,results in a sensitization of thecells to the subsequent presentation of a bathing solutionduring the in vitro determinations of permeability. Withthe continued presence of silicone oil, other pathologicchanges would contribute to longer-term physiologicalteration of the corneal endothelium. As we can find in the group SIO: the cornea istransparent before taken out of silicone oil except fordamage zones. The cornea will be opaque as soon assilicone oil is taken out of anterior chamber. The reasonof this phenomenon may be cornea pump function withoutmanifesting descent, though endothelium corneal isdamaged hardly in decompensation without aqueous humorinto corneal stroma. When we take silicone oil out of eyes,the cornea will be edema because of aqueous humor intocornea inside. Protective screen and initiative liquid pump ofendothelium corneal cells are very important for keepingcornea transparent and normal thickness. Density ofendothelium corneal decreases sharply in the damagedzones after 12 weeks(P<0.01). The thicknesses of corneain the group SI increase gradually, because crude fiber ofendothelium corneal increases by degrees probably. Therefore if the complication happens after vitrecomyduring clinical work, we should keep an eye on theendothelium corneal closely and take steps to save corneapromptly in order to alleviate the damage and save cornea...