Purpose:Corneal thickness assessment is a common clinical procedure applied in corneal and contact lens care. This study aims to investigate the effect of age on hypoxia-induced corneal swelling.Methods:Eighteen male ...Purpose:Corneal thickness assessment is a common clinical procedure applied in corneal and contact lens care. This study aims to investigate the effect of age on hypoxia-induced corneal swelling.Methods:Eighteen male subjects were equally divided into the younger [(23.7 ± 0.8) years old] and older [(74.4 ± 2.5) years old] groups. Each subject wore a thick soft contact lens (uniform thickness of 0.3 mm) on the left cornea. With the contact lens in place, the baseline central corneal thickness was measured using a specially designed photo-pachometer. The lens was then patched behind the closed eyelids, producing an extremely hypoxic stress to the cornea. The change in central corneal thickness was monitored every 20 minutes with momentary disruptions to the hypoxic stress over the next 2 hours. The increase in thickness was taken as an index of corneal edema. The rate of change in corneal thickness, as derived from a non-linear mathematical model, was compared between groups.Results:The corneal thickness of both age groups increased significantly with time (P<0.000 1). The mean corneal swelling constant for the older subjects was 16.5 × 10-3 (S.E.M. = 2.65 × 10-3) and the value for the younger subjects was 46.5 × 10-3 (S.E.M. = 3.25 × 10-3). The difference was statistically significant (P < 0.000 1).Conclusion:Aging cornea has a slower hypoxia-induced edema response compared with the younger group. Whether it is caused by a decreased corneal lactate production or an increased resistance to physical expansion deserves further investigation. Eye Science 2004;20:1-5.展开更多
文摘Purpose:Corneal thickness assessment is a common clinical procedure applied in corneal and contact lens care. This study aims to investigate the effect of age on hypoxia-induced corneal swelling.Methods:Eighteen male subjects were equally divided into the younger [(23.7 ± 0.8) years old] and older [(74.4 ± 2.5) years old] groups. Each subject wore a thick soft contact lens (uniform thickness of 0.3 mm) on the left cornea. With the contact lens in place, the baseline central corneal thickness was measured using a specially designed photo-pachometer. The lens was then patched behind the closed eyelids, producing an extremely hypoxic stress to the cornea. The change in central corneal thickness was monitored every 20 minutes with momentary disruptions to the hypoxic stress over the next 2 hours. The increase in thickness was taken as an index of corneal edema. The rate of change in corneal thickness, as derived from a non-linear mathematical model, was compared between groups.Results:The corneal thickness of both age groups increased significantly with time (P<0.000 1). The mean corneal swelling constant for the older subjects was 16.5 × 10-3 (S.E.M. = 2.65 × 10-3) and the value for the younger subjects was 46.5 × 10-3 (S.E.M. = 3.25 × 10-3). The difference was statistically significant (P < 0.000 1).Conclusion:Aging cornea has a slower hypoxia-induced edema response compared with the younger group. Whether it is caused by a decreased corneal lactate production or an increased resistance to physical expansion deserves further investigation. Eye Science 2004;20:1-5.
文摘目的研究长期配戴(>5 a)软性角膜接触镜(SCL)大学生与未配戴SCL大学生眼表泪膜的差异,探讨SCL长期配戴对眼表泪膜的影响及可能机制。方法依据SCL戴镜时间将SCL戴镜者区分为<5 a组、5～10 a组和>10 a组,共3组。对正常对照组(35人70眼)和病例组(66人132眼)的泪膜破裂时间(BUT)、角膜荧光素染色(FLS)试验和基础泪液分泌试验(Schirmer I test)结果进行比较。结果软性角膜接触镜戴镜时间<5 a组Schirmer I test、FLS与正常对照组比较差异无统计学意义(P值均>0.05),其余各戴镜组BUT、Schirmer I test、FLS与正常对照组差异均有统计学意义(P值均<0.01)。结论长期配戴软性角膜接触镜会引起泪膜功能下降和角膜上皮损伤,且戴镜时间越长,损害越大。
