玻璃体切割术对晶状体氧分压的影响

目的:通过测量兔眼玻璃体和晶状体的氧张力并分析其凋节机制,研究玻璃体切割术对晶状体氧分压的影响。方法:利用光纤测氧仪在活体上测量兔眼玻璃体和晶状体的氧分压分布,并在游离兔眼晶状体上测定晶状体后囊膜对氧的通透性。结果:视网膜附近的玻璃体氧分压较高且氧梯度陡峭,而远离视网膜约0.5 mm的玻璃体氧分压低,氧梯度变缓;晶状体的氧分布不对称,后皮质的氧分压低于前皮质,但和晶状体后的玻璃体氧分压基本一致;晶状体后囊膜对氧的通透性相对高。结论:玻璃体对调节和维持晶状体的低氧环境至关重要;玻璃体切割术会引起晶状体的氧分压升高。

Affection on Oxygen Tension of the Lens after Vitrectomy

Purpose: To measure the oxygen tension (PO2) in the rabbit vitreous and lens and toinvestigate the mechanism by which it is controlled, the affection on oxygen tension of thelens after vitrectomy was studied.Methods: Using a fiber-optic oxygen sensor system, oxygen tension of the rabbit vitreousand lens was probed in vivo and oxygen permeability of posterior capsule was alsomeasured on isolated rabbit lens.Results: It was found that with agreement with previous study, PO2 is relatively high andthe PO2 gradient is large in vitreous body close to the retina whereas more than 0. 5 mmaway from the retina the vitreal PO2 is relatively low and the PO2 gradient is very shallow.Oxygen tension in the lens is asymmetric with the anterior being higher than the posteriorand oxygen in the posterior lens being at the similar tension as the anterior vitreousbehind the lens. The posterior capsule of the rabbit lens is relatively high in oxygenpermeability.Conclusions: The vitreous body plays a key role in maintaining a low and stable level ofoxygen in the lens. After vitrectomy oxygen tension in the lens may increase.