Gozálvez-Zafrilla José M, Aguilella-Arzo Marcel, Compañ Vicente
Institute for Industrial, Radiophysical and Environmental Safety (ISIRYM), Departamento de Ingeniería Química y Nuclear, Universitat Politécnica de Valencia, Campus de Vera, Valencia, Spain.
Departamento de Física, Universitat Jaume I, Castellón, Spain.
Ophthalmic Physiol Opt. 2025 Jul;45(5):1126-1141. doi: 10.1111/opo.13510. Epub 2025 Apr 19.
This three-dimensional study investigated how different contact lens materials affect oxygen levels in the cornea. Specifically, it measured oxygen tension, flux and consumption in the epithelium, stroma and endothelium when exposed to various contact lenses. The goal was to understand how oxygen distribution within the cornea changes based on the oxygen tension at the cornea-tear interface, which is influenced by the lens's oxygen transmissibility.
To achieve this goal, a finite element analysis model was used that accounted for the axisymmetric properties of the cornea. A parametric analysis was conducted to examine how lens power and refractive index impacted oxygen distribution. This involved testing various contact lens materials with different powers (±3 and ±6D) and refractive indices.
This three-dimensional model provides new insights into the flux and concentration profiles of oxygen across the epithelium, stroma and endothelium for contact lenses having different optical powers. The key findings show that contact lens thickness and refractive index, which are related to the power, significantly impact oxygen concentration within the cornea. Notably, reduced corneal oxygen consumption occurs primarily at the epithelium, where oxygen tension decreases under both open-eye and closed-eye conditions. This decrease depends on the oxygen permeability of the contact lens being worn and its power.
The cornea can sustain normal metabolic processes (aerobic metabolism) if the oxygen levels at the cornea-tear film interface are within approximately 60-100 mmHg. This holds true for all of the contact lenses tested here under open-eye conditions. However, when the eyes are closed, the cornea is unable to maintain normal metabolic processes, leading to a shift towards anaerobic metabolism. Prolonged exposure to these conditions can cause corneal oedema (swelling) due to an inadequate oxygen supply.
本三维研究调查了不同的隐形眼镜材料如何影响角膜中的氧含量。具体而言，它测量了暴露于各种隐形眼镜时上皮、基质和内皮中的氧张力、通量和消耗量。目标是了解基于角膜 - 泪液界面处的氧张力（受镜片透氧性影响），角膜内的氧分布如何变化。
为实现这一目标，使用了一个考虑角膜轴对称特性的有限元分析模型。进行了参数分析，以研究镜片度数和折射率如何影响氧分布。这涉及测试具有不同度数（±3和±6D）和折射率的各种隐形眼镜材料。
该三维模型为不同屈光度隐形眼镜的上皮、基质和内皮中的氧通量和浓度分布提供了新的见解。关键发现表明，与度数相关的隐形眼镜厚度和折射率会显著影响角膜内的氧浓度。值得注意的是，角膜氧消耗的减少主要发生在上皮，在睁眼和闭眼条件下，上皮处的氧张力都会降低。这种降低取决于所佩戴隐形眼镜的透氧性及其度数。
如果角膜 - 泪膜界面处的氧含量在大约60 - 100 mmHg范围内，则角膜可以维持正常的代谢过程（有氧代谢）。在睁眼条件下，此处测试的所有隐形眼镜均符合这一情况。然而，当眼睛闭合时，角膜无法维持正常的代谢过程，导致向无氧代谢转变。长时间暴露于这些条件下会因氧气供应不足而导致角膜水肿（肿胀）。
