目的：观察重硅油（Densiron-68）作为长期玻璃体腔填充物对兔眼视网膜组织耐受性情况，为临床应用提供有价值的资料。 方法：健康成年纯种新西兰白兔21只，随机分为实验组（Densiron-68组、硅油组）、对照组。玻璃体切割术后玻璃体腔内分别注入Densiron-68、硅油和平衡盐溶液(BSS) 2mL左右。 手术后定期裂隙灯、间接检眼镜检查及监测眼压。实验组分别于手术后4，8，12wk，对照组于手术后12wk，取兔眼视网膜标本行光镜及电镜组织学检查。 结果：实验组及对照组观察期内角膜均维持透明，无玻璃体出血及眼内炎等并发症发生。各组手术前后眼压及组间眼压无统计学差异。Dension-68、硅油在玻璃体腔内形成单个透明泡，手术后3～8wk可见到Densiron-68乳化。对照组、硅油组实验眼术后均未观察到白内障形成。Densiron-68组1眼晶状体在术后4wk开始出现晶状体后囊下点状混浊，随时间延长而缓慢发展。未见视网膜脱离。实验组光学显微镜下未见明显视网膜组织结构异常。实验组经透射电子显微镜检查，Densiron-68组上方视网膜在各个观察期均未见明显超微结构改变，下方视网膜在术后4wk可见个别光感受器内节线粒体轻度肿胀；8wk时可见到个别内节线粒肿胀加重，个别视网膜光感受器外节模糊不清；其余大多数光感受器外节膜盘形态正常、排列整齐；12wk的标本中仅见个别光感受器内节线粒体轻度肿胀，膜盘大致正常。硅油组术后仅12wk时可见小部分上方内颗粒层线粒体轻度肿胀。对照组组织学检查未见异常。 结论：作为长期玻璃体替代物，兔眼视网膜对Densiron-68的耐受性良好,虽易早期发生乳化，制约其临床应用效果,但在目前仍不失为一种选择，其乳化后是否会对角膜及房角产生毒性反应，尚待进一步研究。

To investigate intraocular tolerance to heavy silicone oil (Densiron-68) as a long-term vitreous substitute in the experimental animal and to provide reference for further clinical test and application. METHODS: Twenty-one New Zealand albino rabbits, weighing 2.2 to 2.5kg, underwent pars plana vitrectomy of the left eye. Animals were randomized in 3 groups: group 1: Densiron-68 group, 9 rabbits; group 2: silicone oil group, 9 rabbits; group 3: 3 rabbits eyes were injected balanced salt solution(BSS) as a control group. During the follow-up period, the eyes were examined by slit-lamp biomicroscopy and indirect ophthalmoscopy, and the intraocular pressure was measured by Schiotz tonometer. The eyes were then enucleated at the 4^th,-8^th and 12^nd week after surgery respectively and processed for light microscope and transmission electron microscope. RESULTS: Throughout the observation period in all groups there was unremarkable findings of the retina,optic nerve,and no corneal edema, intraocular hemorrhage, endophthalmitis were noticed. No statistic difference of intraocular pressure was noticed between control group and two experiment groups or within each group preoperatively or postoperatively. A large clear bubble was formed after Densiron-68,-silicone oil were injected into vitreous cavity. Densiron-68 depicted dispersion beginning between 3^rd and 8^th week. Only one posterior subcapsular lens opacity was observed in Densiron-68 tamponade group. Histological evaluation of the retina exposed to Densiron-68 or silicone oil showed normal retinal structures by light microscopic examination. The mitochondria swollen in the inferior photoreceptor inner segment were observed after 4 weeks in Densiron-68 injection group. The changes mentioned above were more remarkable after 8 weeks. But only a few mitochondria in the photoreceptor inner segment were swollen slightly after 12 weeks. The similar changes were in inner nuclear layer(INL) cell in the superior retina after 12 weeks in silicone oil tamponade group. CONCLUSION: Densiron-68 can be well tolerated by retinas of rabbit, although its propensity to disperse, the availability of Densiron-68 may add to our repertoire in managing selected RD. The mitochondria swollen in the inferior photoreceptor inner segment are observed in Densiron-68 injection groupe. It needs more study to evaluate the damage to anterior chamber and cornea. Densiron-68 should not be used to silicone oil-dependent patient because its propensity to disperse and should be extracted as soon as possible after retina reposition.