软性隐形眼镜佩戴预防局部角膜高渗峰值。
Prevention of localized corneal hyperosmolarity spikes by soft-contact-lens wear.
机构信息
Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, CA 94720, United States; Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94720, United States; Clinical Research Center, University of California, Berkeley, CA 94720, United States.
Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, CA 94720, United States; Clinical Research Center, University of California, Berkeley, CA 94720, United States.
出版信息
Cont Lens Anterior Eye. 2022 Dec;45(6):101722. doi: 10.1016/j.clae.2022.101722. Epub 2022 Jun 16.
PURPOSE
To determine whether localized hyperosmotic spikes on the pre-lens tear film (PrLTF) due to tear break up results in hyperosmotic spikes on the ocular surface during soft-contact-lens (SCL) wear and whether wear of SCLs can protect the cornea against PrLTF osmotic spikes.
METHODS
Two-dimensional transient diffusion of salt was incorporated into a computationally designed SCL, post-lens tear film (PoLTF), and ocular surface and solved numerically. Time-dependent localized hyperosmolarity spikes were introduced at the anterior surface of the SCL corresponding to those generated in the PrLTF. Salt spikes were followed in time until spikes penetrate through the lens into the PoLTF. Lens-salt diffusivities (D) were varied to assess their importance on salt migration from the PrLTF to the ocular surface. SCL and PoLTF initial conditions and the lens anterior-surface boundary condition were varied depending on the value of D and on dry-eye symptomatology. Determined corneal surface osmolarities were translated into clinical pain scores.
RESULTS
For D above about 10cm/s, it takes around 5-10 s for the PrLTF hyperosmotic break-up spikes to diffuse across the SCL and reach the corneal surface. Even if localized hyperosmotic spikes penetrate to the ocular surface, salt concentrations there are much lower than those in the progenitor PrLTF spikes. For D less than 10cm/s, the SCL protects the cornea from hyperosmotic spikes for both normal and dry eyes. When localized corneal hyperosmolarity is converted into transient pain scores, pain thresholds are significantly lower than those for no-lens wear.
CONCLUSIONS
A cornea can be protected from localized PrLTF hyperosmolarity spikes with SCL wear. With regular blinking (e.g., less than 10 s), SCL wear shields the cornea from significant hyperosmotic pain. Decreasing D increases that protection. Low-D soft contact lenses can protect against hyperosmotic spikes and discomfort even during infrequent blinking (e.g., > 10 s).
目的
确定由于泪膜破裂而在前泪膜（PrLTF）上产生的局部高渗峰是否会导致软性隐形眼镜（SCL）佩戴期间眼表出现高渗峰，以及 SCL 的佩戴是否可以保护角膜免受 PrLTF 渗透峰的影响。
方法
在计算设计的 SCL、后泪膜（PoLTF）和眼表面中引入二维盐瞬时扩散，并进行数值求解。在 SCL 的前表面引入与 PrLTF 中产生的对应时间相关的局部高渗透压尖峰。随着时间的推移跟踪盐尖峰，直到尖峰穿透镜片进入 PoLTF。改变镜片-盐扩散系数（D）以评估其对盐从 PrLTF 向眼表面迁移的重要性。根据 D 的值和干眼症症状，改变 SCL 和 PoLTF 的初始条件以及镜片前表面边界条件。将确定的角膜表面渗透压转换为临床疼痛评分。
结果
对于 D 值高于约 10cm/s，PrLTF 高渗透压破裂尖峰大约需要 5-10 秒才能扩散穿过 SCL 并到达角膜表面。即使局部高渗透压尖峰穿透到眼表面，那里的盐浓度也远低于前体 PrLTF 尖峰的浓度。对于 D 值小于 10cm/s，SCL 可以保护角膜免受高渗透压尖峰的影响，无论是正常眼睛还是干眼症。当局部角膜高渗透压转化为短暂的疼痛评分时，疼痛阈值明显低于无镜片佩戴时的疼痛阈值。
结论
SCL 佩戴可以保护角膜免受局部 PrLTF 高渗透压尖峰的影响。通过定期眨眼（例如，小于 10 秒），SCL 佩戴可以保护角膜免受显著的高渗透压疼痛。降低 D 值会增加这种保护作用。即使在不频繁眨眼（例如，> 10 秒）的情况下，低 D 值的软性隐形眼镜也可以保护眼睛免受高渗透压尖峰和不适的影响。
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