McGinty S J, Truscott R J W
Save Sight Institute, Sydney, and Institute for Biomolecular Science, University of Wollongong, Wollongong, Australia.
Ophthalmic Res. 2006;38(3):137-48. doi: 10.1159/000090645. Epub 2006 Jan 3.
Presbyopia, the inability to accommodate, affects almost everyone at middle age. Recently, it has been shown that there is a massive increase in the stiffness(1) of the lens with age and, since the shape of the lens must change during accommodation, this could provide an explanation for presbyopia. In this review, we propose that presbyopia may be the earliest observable symptom of age-related nuclear (ARN) cataract. ARN cataract is a major cause of world blindness. The genesis of ARN cataract can be traced to the onset of a barrier within the lens at middle age. This barrier restricts the ability of small molecules, such as antioxidants, to penetrate into the centre of the lens leaving the proteins in this region susceptible to oxidation and post-translational modification. Major protein oxidation and colouration are the hallmarks of ARN cataract. We postulate that the onset of the barrier, and the hardening of the nucleus, are intimately linked. Specifically, we propose that progressive age-dependent hardening of the lens nucleus may be responsible for both presbyopia and ARN cataract.
老花眼，即无法进行调节，几乎影响到每一个中年人。最近的研究表明，晶状体的硬度会随着年龄的增长而大幅增加，而且由于晶状体的形状在调节过程中必须发生变化，这可能为老花眼提供一种解释。在这篇综述中，我们提出老花眼可能是年龄相关性核性（ARN）白内障最早可观察到的症状。ARN白内障是全球失明的主要原因。ARN白内障的成因可追溯到中年时晶状体内部屏障的出现。这个屏障限制了小分子（如抗氧化剂）渗透到晶状体中心的能力，使得该区域的蛋白质容易受到氧化和翻译后修饰的影响。主要的蛋白质氧化和颜色变化是ARN白内障的特征。我们推测屏障的出现与晶状体核的硬化密切相关。具体而言，我们提出晶状体核随年龄增长的渐进性硬化可能是老花眼和ARN白内障的共同原因。
