Holden B A, McNally J J, Egan P
Cornea and Contact Lens Research Unit, School of Optometry, University of New South Wales, Sydney, Australia.
Curr Eye Res. 1988 Jun;7(6):601-5. doi: 10.3109/02713688809031816.
Topographical corneal thickness changes were monitored in 10 subjects who each wore a hydrogel contact lens with a large central aperture ("donut" lens) for 6 hours. Analysis of local corneal thickness changes indicates that no corneal swelling occurred in the central exposed area of the cornea, but significant swelling occurred in the area of the cornea covered by the lens. The lateral cut-off point of corneal swelling was well-defined, indicating that the contact lens-induced corneal edema did not spread laterally to the exposed area of the cornea over the six-hour wearing period. Swelling of the peripheral cornea covered by the lens was found to be significantly greater with a tightly-fitting, immobile donut lens than with a loosely-fitting lens, suggesting that tear mixing may explain in part the apparent averaging of edema during open-eye wear of hydrogel lenses of varying thickness profile. The possibility that lateral spread of lactate within the stroma may contribute to this apparent averaging of edema was not confirmed in this study. We suggest that rapid metabolism or elimination of lactate in the exposed region of the cornea, or evaporation through the central lens aperture, may have contributed to the maintenance of normal central corneal thickness during open-eye wear of the donut lens.
对10名受试者进行了角膜厚度变化监测，每位受试者佩戴中央有大孔径的水凝胶隐形眼镜（“甜甜圈”镜片）6小时。对局部角膜厚度变化的分析表明，角膜中央暴露区域未发生角膜肿胀，但镜片覆盖的角膜区域出现了明显肿胀。角膜肿胀的外侧界限清晰，表明在6小时的佩戴期间，隐形眼镜引起的角膜水肿未横向扩散至角膜暴露区域。发现佩戴紧密贴合、固定不动的甜甜圈镜片时，镜片覆盖的周边角膜肿胀明显大于佩戴宽松镜片时，这表明泪液混合可能在一定程度上解释了不同厚度剖面的水凝胶镜片睁眼佩戴期间水肿的明显平均化现象。本研究未证实基质内乳酸的横向扩散可能导致这种水肿明显平均化的可能性。我们认为，角膜暴露区域乳酸的快速代谢或消除，或通过中央镜片孔径的蒸发，可能有助于在睁眼佩戴甜甜圈镜片期间维持角膜中央厚度正常。
