Fatt I, Weissman B A, Ruben C M
School of Optometry, University of California, Berkeley 94720.
CLAO J. 1993 Oct;19(4):226-34.
If there is little lateral diffusion of oxygen in an optically powered hydrogel contact lens, then point-to-point differences in the thickness of the lens can result in different areas of the cornea receiving different amounts of oxygen. Specifically, areas under the thicker portions of the lens will receive less oxygen. Cells in these oxygen-deprived areas may produce metabolic products that spread laterally in the cornea resulting in cornea-wide edema. The fact that most of a contact lens transmits adequate oxygen to the cornea does not lead to satisfactory lens performance, if some part of the lens is too thick. We address the problem of lateral diffusion of oxygen in a contact lens and describe the methods for quantifying the point-to-point thickness of optically powered hydrogel lenses. Areal differences in oxygen supply to the cornea are found to be almost totally dependent on optical power; water content and lens design have far less effect.
如果在光动力水凝胶隐形眼镜中氧气的横向扩散很少，那么镜片厚度的逐点差异会导致角膜的不同区域接受不同量的氧气。具体而言，镜片较厚部分下方的区域将接受较少的氧气。这些缺氧区域的细胞可能会产生代谢产物，这些代谢产物在角膜中横向扩散，导致全角膜水肿。如果隐形眼镜的某些部分太厚，即使其大部分能将足够的氧气传输到角膜，也不会带来令人满意的镜片性能。我们解决了隐形眼镜中氧气横向扩散的问题，并描述了量化光动力水凝胶镜片逐点厚度的方法。发现角膜氧气供应的区域差异几乎完全取决于光焦度；含水量和镜片设计的影响要小得多。
