一种新的基于镜面反射的兔模型眼前部泪膜稳定性测量技术：粘弹性增加泪膜稳定性。
A new, specular reflection-based, precorneal tear film stability measurement technique in a rabbit model: viscoelastic increases tear film stability.
机构信息
Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States.
Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States Anne Bates Leach Eye Hospital, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States.
出版信息
Invest Ophthalmol Vis Sci. 2014 Jun 19;55(7):4158-63. doi: 10.1167/iovs.14-14157.
PURPOSE
To develop a safe, noninvasive, noncontact, continuous in vivo method to measure the dehydration rate of the precorneal tear film and to compare the effectiveness of a viscoelastic agent in maintaining the precorneal tear film to that of a balanced salt solution.
METHODS
Software was designed to analyze the corneal reflection produced by the operating microscope's coaxial illumination. The software characterized the shape of the reflection, which became distorted as the precorneal tear film evaporated; characterization was accomplished by fitting an ellipse to the reflection and measuring its projected surface area. Balanced salt solution Plus (BSS+) and a 2% hydroxypropylmethylcellulose viscoelastic were used as the test agents. The tear film evaporation rate was characterized and compared over a period of 20 minutes in 20 eyes from 10 New Zealand white rabbits.
RESULTS
The ellipse axes ratio and surface area were found to decrease initially after each application of either viscoelastic or BSS+ and then to increase linearly as the tear film began to evaporate (P < 0.001) for eyes treated with BSS+ only. Eyes treated with BSS+ required 7.5 ± 2.7 applications to maintain sufficient corneal hydration during the 20-minute test period, whereas eyes treated with viscoelastic required 1.4 ± 0.5 applications. The rates of evaporation differed significantly (P < 0.043) between viscoelastic and BSS+.
CONCLUSIONS
The shape and surface area of the corneal reflection are strongly correlated with the state of the tear film. Rabbits' corneas treated with viscoelastic remained hydrated significantly longer than corneas treated with BSS+.
目的
开发一种安全、非侵入性、非接触性、连续的活体方法来测量角膜前泪膜的脱水率，并比较粘弹性剂维持角膜前泪膜的效果与平衡盐溶液的效果。
方法
设计软件来分析手术显微镜同轴照明产生的角膜反射。软件对反射的形状进行特征描述，当角膜前泪膜蒸发时，反射会变形；通过拟合椭圆来实现特征描述，并测量其投影表面积。平衡盐溶液 Plus（BSS+）和 2%羟丙基甲基纤维素粘弹性剂被用作测试剂。在 10 只新西兰白兔的 20 只眼睛中，在 20 分钟的时间内，对泪膜蒸发率进行了特征描述和比较。
结果
发现无论是粘弹性剂还是 BSS+，每次应用后，椭圆轴比和表面积最初都会减小，然后随着泪膜开始蒸发，它们会呈线性增加（P<0.001），仅用 BSS+处理的眼睛。在 20 分钟的测试期间，用 BSS+处理的眼睛需要 7.5±2.7 次应用才能保持足够的角膜水合作用，而用粘弹性剂处理的眼睛仅需要 1.4±0.5 次应用。蒸发率在粘弹性剂和 BSS+之间有显著差异（P<0.043）。
结论
角膜反射的形状和表面积与泪膜状态密切相关。用粘弹性剂处理的兔子角膜比用 BSS+处理的角膜保持水合作用的时间明显更长。
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