Instituto de Óptica, Daza de Valdés, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
J Refract Surg. 2013 Jul;29(7):490-7. doi: 10.3928/1081597X-20130617-08.
To evaluate corneal deformation with varying intraocular pressure and the dependency of the biomechanical response on the corneal hydration state, modulated by the storage solutions or postmortem period.
Thirty fresh enucleated porcine eyes were used for in vitro whole eye globe inflation experiments. The eyes were separated into five groups and treated with different solutions: 20% dextran, 8% dextran, 0.125% riboflavin-20% dextran, Optisol-GS (Bausch & Lomb, Rochester, NY), and one control group of virgin (untreated) eyes. Intraocular pressure was increased (from 15 to 55 mm Hg) and decreased (to 15 mm Hg) in 5-mm Hg steps and Scheimpflug images were taken at each step. Measurements were repeated after 24 hours. Thickness and curvature changes were analyzed as a function of intraocular pressure.
Corneal deformation differed across conditions and hydration states. Dehydration by any dextran solution increased the hysteresis after the inflation/deflation cycle (14.29 vs 22.07 to 41.75 μm), whereas overnight hydration did not lead to a significant difference. Compared to control corneas, corneas treated with Optisol-GS showed the most similar behavior. Corneas treated with 0.125% riboflavin-20% dextran deformed most (Δthickness(max) = 38.27 μm), indicating a softening of the corneal tissue compared to control corneas (23.18 μm) and corneas treated with 8% dextran (21.01 μm) and 20% dextran (29.07 μm). Dextran instillation decreased corneal thickness on average to 56.5% at 0 hours and 72.7% at 24 hours.
Corneal hydration and tissue preservation changed corneal biomechanics, in particular its relaxation over a period of 24 hours.
评估眼内压变化时的角膜变形，并评估角膜水合状态变化时生物力学响应的依赖性，这些变化由储存液或死后时间调节。
对 30 只新鲜猪眼进行体外全眼球膨胀实验。将眼球分为五组，并分别用不同的溶液处理：20%葡聚糖、8%葡聚糖、0.125%核黄素-20%葡聚糖、Optisol-GS（美国罗彻斯特的 Bausch & Lomb）和一组未处理（未处理）的对照眼。眼内压以 5mmHg 的步长从 15mmHg 增加（增加到 55mmHg）和降低（降低到 15mmHg），并在每个步长拍摄 Scheimpflug 图像。24 小时后重复测量。分析厚度和曲率变化与眼内压的关系。
角膜变形因条件和水合状态而异。任何葡聚糖溶液的脱水都会增加充气/放气循环后的滞后（14.29 对 22.07 到 41.75μm），而过夜水合不会导致显著差异。与对照角膜相比，Optisol-GS 处理的角膜表现出最相似的行为。与对照角膜（23.18μm）和 8%葡聚糖（21.01μm）和 20%葡聚糖（29.07μm）相比，用 0.125%核黄素-20%葡聚糖处理的角膜变形最大（Δ厚度（max）=38.27μm），表明角膜组织变软。葡聚糖滴注可使角膜厚度在 0 小时时平均降低至 56.5%，在 24 小时时降低至 72.7%。
角膜水合和组织保存改变了角膜生物力学，特别是在 24 小时内的松弛。
