The Functional And Histopathologic Effect Of Perfluorocarbone Gas For Intravitrous Tamponade On Retina

OBJECTIVE: To evaluate functional and histopathologic retinal changes and possible cell apoptosis in eyes after injection of pure perfluoropropane (C3F8),pure perfluoroethane (C2F6) into vitreous cavity.Methods: Twenty pigmented rabbits were divided into three groups: single injection ,repeated injections and control group.C3F8 gas and C2F6 gas (0.4mL each)were injected into rabbit vitreous cavities, left and right eye respectively. The intravitreous bubble volumes of the repeated injections group were kept more than 0.4ML by repeatedly injecting gas. FERG were recorded before and after the injection to assess the functional changes of retina. At the 30d,50d and 80d ,light and electron microscopic examinations as well as TUNEL technique were conducted to investigate histopathological retinal changes. 0.4mL balanced salt solution(BSS) were injected into the control group.Result: Mean b-wave amplitude of scotopic ERG were remarkably reduced at the 3d postoperatively. The b-wave amplitude returned gradually to normal in the single injection group. Whereas eyes in repeated injection group didn't. At all points, thinning of outer plexiform layer and variable degrees of atrophy with disappearance of out and inner segments of photoreceptors were found in eyes that received C3F8 gas or C2F6 gas repeately. In all eyes that received gas, light and electron microscopy showed that the inferior retina were the same as in control at all time points. The superior retina of the right eye were similar to the left one. The TUNEL technology showed that apoptosis cell were presented in all sections with more pronounce in the repeated injection group.Conclusion: Retinal tamponade using perflorocarbone gas for a long-term induces irreversible functional changes of retina of the rabbit eye. Tamponade with gas is detrimental primarily to the outer layer of superior retina. The damage of gas tamponade to retina is closely related to the buoyancy force retention during the bubble, and not to the kind of gas used.