Many parameters affect tear film thickness and fluorescent intensity distributions over time; exact values or ranges for some are not well known. We conduct parameter estimation by fitting to fluorescent intensity data recorded from normal subjects’ tear films. The fitting is done with thin film fluid dynamics models that are nonlinear partial differential equation models for the thickness, osmolarity and fluorescein concentration of the tear film for circular (spot) or linear (streak) tear film breakup. The corresponding fluorescent intensity is computed from the tear film thickness and fluorescein concentration. The least squares error between computed and experimental fluorescent intensity determines the parameters. The results vary across subjects and trials. The optimal values for variables that cannot be measured in vivo within tear film breakup often fall within accepted experimental ranges for related tear film dynamics; however, some instances suggest that a wider range of parameter values may be acceptable.

中文翻译：

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蒸发驱动泪膜变薄的参数估计

许多参数会随着时间的推移影响泪膜厚度和荧光强度分布；一些的确切值或范围并不为人所知。我们通过拟合从正常受试者泪膜记录的荧光强度数据来进行参数估计。拟合是用薄膜流体动力学模型完成的，这些模型是圆形（点）或线性（条纹）泪膜破裂的泪膜厚度、渗透压和荧光素浓度的非线性偏微分方程模型。根据泪膜厚度和荧光素浓度计算相应的荧光强度。计算和实验荧光强度之间的最小二乘误差决定了参数。结果因受试者和试验而异。在泪膜破裂内无法在体内测量的变量的最佳值通常落在相关泪膜动力学的可接受实验范围内；然而，一些实例表明更广泛的参数值可能是可以接受的。