Purpose

While changes in meibum quality are correlated with severity of meibomian gland dysfunction (MGD) and dry eye disease, little is known regarding the mechanics of meibum secretion. The purpose of this study was to develop a finite element model of meibum secretion and evaluate the effect of various factors that might impact meibum delivery to the eyelid.

Methods

A finite element analysis in COMSOL 6.0 was used to simulate the flow of meibum within the gland's terminal excretory duct. Historical normal human meibum rheology data taken over the meibum melting range from fluid (35–40 °C) to solid (25–30 °C) were then used to calculate the minimum yield stress and plastic viscosity of meibum. The effects of meibum melting state, eyelid pressure and terminal duct diameter on meibum flow rates were then systematically investigated.

Results

The melting state of meibum from liquid to solid was associated with an increase in the minimum yield stress and plastic viscosity that caused an exponential decrease in meibum flow. Modeling also established that there was a linear correlation between meibum flow rate and eyelid pressure needed to express meibum and the 4th power of the terminal duct radius.

Conclusions

Our results suggest that changes in the melting state of meibum from fluid to solid, as well as changes in the radius of the terminal excretory duct and the force exerted by the eyelid can lead to dramatic decreases in the flow of meibum. Together these findings suggest alternative mechanisms for meibomian gland obstruction.

中文翻译：

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睑板腺分泌建模：阻塞性睑板腺功能障碍 (MGD) 的替代方案

目的

虽然睑脂质量的变化与睑板腺功能障碍（MGD）和干眼病的严重程度相关，但人们对睑脂分泌的机制知之甚少。本研究的目的是开发睑脂分泌的有限元模型，并评估可能影响睑脂输送到眼睑的各种因素的影响。

方法

使用 COMSOL 6.0 中的有限元分析来模拟腺体末端排泄管内睑脂的流动。然后使用从液体（35-40°C）到固体（25-30°C）的睑脂熔化范围内获取的历史正常人类睑脂流变学数据来计算睑脂的最小屈服应力和塑性粘度。然后系统地研究了睑脂融化状态、眼睑压力和末端导管直径对睑脂流速的影响。

结果

睑脂从液体到固体的熔化状态与最小屈服应力和塑性粘度的增加有关，这导致睑脂流动呈指数下降。建模还证实，睑脂流速和挤出睑脂所需的眼睑压力以及末端导管半径的四次方之间存在线性相关性。

结论

我们的结果表明，睑脂熔化状态从液体到固体的变化，以及末端排泄管半径和眼睑施加的力的变化，可以导致睑脂流量急剧减少。这些发现共同提出了睑板腺阻塞的替代机制。