A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye
A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye
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DOI：
10.1016/j.preteyeres.2009.11.002
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发表时间：
2010-01-01
影响因子：
17.8
通讯作者：
Bron, A. J.
中科院分区：
文献类型：
--
作者：
Gaffney, E. A.;Tiffany, J. M.;Bron, A. J.
泪液高渗被认为在干眼的发病机制中起关键作用，干眼是一种常见的症状性疾病，伴随着视力障碍、泪膜不稳定、炎症和眼表损伤。我们建立了泪液的质量和溶质平衡模型，并在大量文献数据的基础上进行了参数估计，探讨了泪液蒸发、泪液流量和眨眼速度对泪液渗透压的影响。特别是，在缺水(ADDS)和蒸发性(EDE)干眼中，代偿事件的性质已经被估计。该模型再现了健康眼睛泪液半月板的观察到的渗透压，并预测在正常和干眼状态下泪膜中的浓度高于半月板。这种差异在正常眼中很小，但在干眼中显著增加，特别是在半月板密度高和半月板半径低的同时存在时。这可能会影响从半月板样本获得的渗透压值的解释，因为它们不需要完全反映泪膜高渗透对眼表面的潜在损害。模型的解释表明，眨眼频率的增加在补偿ADS患者泪液渗透压升高方面可能起到有限的作用，但泪液流量的增加以及眨眼频率的增加可能会延缓EDE的高渗透压的发展。尽管如此，据预测，在泪膜破裂开始之前，EDE的泪液渗透压可能会上升到比ADDE高得多的水平，因为眼表没有发生独立影响泪膜稳定性的事件。与EDE或混合性疾病对特定条件的预测反应相比，ADS眼前泪液预测反应的差异表明，没有一个单一的、经验上可获得的变量可以替代泪膜浓度和潜在的眼表损伤。这强调了衡量和整合多个诊断指标以确定结果和预后的必要性。此外，模型预测还显示，关于EDE高泪液流量表型的可能性的进一步研究可能是有益的。(C)2009爱思唯尔有限公司。保留所有权利。
Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model for the mass and solute balance of the tears, with parameter estimation based on extensive data from the literature which permits the influence of tear evaporation, lacrimal flux and blink rate on tear osmolarity to be explored. In particular the nature of compensatory events has been estimated in aqueous-deficient (ADDS) and evaporative (EDE) dry eye.The model reproduces observed osmolarities of the tear meniscus for the healthy eye and predicts a higher concentration in the tear film than meniscus in normal and dry eye states. The differential is small in the normal eye, but is significantly increased in dry eye, especially for the simultaneous presence of high meniscus concentration and low meniscus radius. This may influence the interpretation of osmolarity values obtained from meniscus samples since they need not fully reflect potential damage to the ocular surface caused by tear film hyperosmolarity.Interrogation of the model suggests that increases in blink rate may play a limited role in compensating for a rise in tear osmolarity in ADDS but that an increase in lacrimal flux, together with an increase in blink rate, may delay the development of hyperosmolarity in EDE. Nonetheless, it is predicted that tear osmolarity may rise to much higher levels in EDE than ADDE before the onset of tear film breakup, in the absence of events at the ocular surface which would independently compromise tear film stability. Differences in the predicted responses of the pre-ocular tears in ADDS compared to EDE or hybrid disease to defined conditions suggest that no single, empirically-accessible variable can act as a surrogate for tear film concentration and the potential for ocular surface damage. This emphasises the need to measure and integrate multiple diagnostic indicators to determine outcomes and prognosis. Modelling predictions in addition show that further studies concerning the possibility of a high lacrimal flux phenotype in EDE are likely to be profitable. (C) 2009 Elsevier Ltd. All rights reserved.