Variability in hypoxia-induced corneal swelling is associated with variability in corneal metabolism and endothelial function.
Variability in hypoxia-induced corneal swelling is associated with variability in corneal metabolism and endothelial function.
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DOI：
10.1097/01.icl.0000062462.73172.18
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发表时间：
2003-04-01
期刊：
影响因子：
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通讯作者：
Bonanno, Joseph A
中科院分区：
文献类型：
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作者：
Nguyen, Tracy;Soni, P Sarita;Bonanno, Joseph A
目的：确定隐形眼镜引起的角膜肿胀变异性是否与角膜耗氧量（Q(C)）或角膜内皮功能的变异性有关。方法：30例非隐形眼镜佩戴者使用相同设计的厚（透氧率[Dk/t] = 4.0 × 10-9）和薄（Dk/t = 12 × 10-9）水凝胶隐形眼镜，闭眼佩戴2小时后诱导角膜肿胀。诱导肿胀后，继续用厚测法测量角膜厚度，直到达到睁眼稳态（OESS）厚度。计算每小时恢复的百分比，作为衡量内皮功能的指标。在睁开眼和闭眼5分钟后测量水凝胶下的泪液氧张力（PO(2)），以获得Q(C)的估计值。在佩戴水凝胶闭眼期间，角膜pH值的变化被用作缺氧酸中毒的衡量标准。还测试了角膜肿胀与内皮细胞密度或角膜上皮厚度之间的关系。结果：厚晶状体角膜肿胀与厚晶状体闭眼PO(2)有中度但显著的相关性（P < 0.05） （r = -0.36）；薄晶状体角膜肿胀和薄晶状体闭眼和睁眼PO(2) （r分别= -0.40和-0.39）。角膜肿胀也随着Q(C)的增加而增加（r = + 0.29 ~ + 0.33）。角膜肿胀与晶状体佩戴期间pH值的降低有关（对于厚晶状体和薄晶状体，r分别为+ 0.30和+ 0.20）。厚晶状体和薄晶状体角膜肿胀与每小时恢复百分比显著相关（r分别= -0.40和-0.34）。对PO(2)角膜肿胀和每小时恢复百分比的多元回归分析表明存在叠加效应，但效果不显著。角膜肿胀与OESS之间存在适度的负相关，但角膜肿胀与内皮细胞密度或上皮细胞厚度之间没有关联。结论：隐形眼镜引起的角膜肿胀变异性与角膜代谢活性（Q(C)和pH）和内皮功能（每小时恢复百分比）有关。我们的解释是，较大的Q(C)个体产生更多的乳酸（即更多的肿胀），而更强的内皮功能抵抗肿胀。然而，这种适度的相关性表明，其他因素也参与了角膜肿胀现象的解释。
PURPOSE: To determine if the variability in contact lens-induced corneal swelling is associated with variability in corneal oxygen consumption (Q(C)) or corneal endothelial function.METHODS: Corneal swelling was induced in 30 non-contact lens wearers by 2 hours of closed-eye contact lens wear, using thick (oxygen transmission [Dk/t] = 4.0 x 10-9) and thin (Dk/t = 12 x 10-9) hydrogel lenses of identical design. Following the induction of swelling, corneal thickness was continually measured by pachymetry until open-eye steady-state (OESS) thickness was achieved. The percentage of recovery per hour was calculated as a measure of endothelial function. Tear oxygen tension (PO(2)) beneath the hydrogels was measured in the open eye and after 5 minutes of eye closure to obtain estimates of Q(C). A change in corneal pH during eye closure while wearing the hydrogels was used as a measure of hypoxic acidosis. Associations between corneal swelling and endothelial cell density or corneal epithelial thickness were also tested.RESULTS: There were modest but significant (P < 0.05) correlations between thick-lens corneal swelling and thick-lens closed-eye PO(2) (r = -0.36); thin lens corneal swelling and thin-lens closed-eye and open-eye PO(2) (r = -0.40 and -0.39, respectively). Corneal swelling also increases with increasing Q(C) (r = + 0.29 to + 0.33). Corneal swelling was associated with the decrease in pH during lens wear (r = + 0.30 and + 0.20 for thick and thin lenses, respectively). Thick- and thin-lens corneal swelling was significantly associated with percentage of recovery per hour (r = -0.40 and -0.34, respectively). Multiple regression analysis of corneal swelling with PO(2) and percentage of recovery per hour suggested an additive effect, however the effects were not significant. There was a modest inverse association between corneal swelling and OESS, however there were no associations between corneal swelling and endothelial cell density or epithelial thickness.CONCLUSIONS: The variability in contact lens-induced corneal swelling is associated with both corneal metabolic activity (Q(C) and pH) and endothelial function (percentage of recovery per hour). Our interpretation is that individuals with larger Q(C) produce more lactic acid (i.e., more swelling) whereas stronger endothelial function resists swelling. The modest correlations, however, suggest that other factors also are involved in explaining the phenomenon of corneal swelling.