Crystalline lens and refractive development
Crystalline lens and refractive development
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DOI：
10.1016/j.preteyeres.2015.02.002
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发表时间：
2015-07-01
影响因子：
17.8
通讯作者：
Iribarren, Rafael
中科院分区：
文献类型：
--
作者：
Iribarren, Rafael
个体屈光不正通常会随着寿命的延长而改变。大多数儿童在幼年时期就有远视。这种远视通常在成长过程中消失，导致成人正视，但儿童在上学期间或成年早期也会出现近视。那些保持正视的受试者在中年容易发生远视转变。甚至在年龄较大的时候，近视的变化会随着核性白内障的发展而发展。早产儿的眼睛从15 mm长到成年早期的大约24 mm，但在大多数情况下，屈光度保持稳定的簇状分布。眼轴长度的这种增长代表着超过40个屈光度的屈光度变化，这被角膜和晶状体屈光度的变化所补偿。在生长过程中维持眼部折射成分之间的平衡的过程仍在研究中，由于晶状体屈光度不能在体内测量，只能根据其他眼成分来计算，因此还没有太多关于人类晶状体屈光度的研究。然而，最近的研究证实，在儿童的成长过程中，晶状体会失去动力，成年后的远视和近视变化也可能是由于晶状体的变化造成的。这些针对儿童和成人的研究描绘了晶状体随寿命的变化情况。最近关于晶状体生长及其内部结构的复杂性的其他研究为这些晶状体倍数的变化是如何随着生命的发展而产生的提供了线索。(C)2015爱思唯尔有限公司。保留所有权利。
Individual refractive errors usually change along lifespan. Most children are hyperopic in early life. This hyperopia is usually lost during growth years, leading to emmetropia in adults, but myopia also develops in children during school years or during early adult life. Those subjects who remain emmetropic are prone to have hyperopic shifts in middle life. And even later, at older ages, myopic shifts are developed with nuclear cataract.The eye grows from 15 mm in premature newborns to approximately 24 mm in early adult years, but, in most cases, refractions are maintained stable in a clustered distribution. This growth in axial length would represent a refractive change of more than 40 diopters, which is compensated by changes in corneal and lens powers. The process which maintains the balance between the ocular components of refraction during growth is still under study.As the lens power cannot be measured in vivo, but can only be calculated based on the other ocular components, there have not been many studies of lens power in humans. Yet, recent studies have confirmed that the lens loses power during growth in children, and that hyperopic and myopic shifts in adulthood may be also produced by changes in the lens. These studies in children and adults give a picture of the changing power of the lens along lifespan. Other recent studies about the growth of the lens and the complexity of its internal structure give clues about how these changes in lens power are produced along life. (C) 2015 Elsevier Ltd. All rights reserved.