Zadnik K, Mutti D O, Fusaro R E, Adams A J
School of Optometry, University of California, Berkeley 94720-2020, USA.
Invest Ophthalmol Vis Sci. 1995 Jul;36(8):1581-7.
Most earlier studies indicated that the eye's crystalline lens grows continually throughout life, but cross-sectional results of crystalline lens thinning during childhood have been reported. The authors investigated crystalline lens thickness in childhood using cross-sectional and longitudinal data.
The Orinda Longitudinal Study of Myopia is a community-based study of normal eye growth and myopia development in school-age children. During a 1-to 3-year period, A-scan ultrasonographic lens thickness measurements of 869 children 6 through 14 years of age were analyzed.
On average, between the ages of 6 and 10 years, the crystalline lens thins in its axial dimension by almost 0.2 mm. This thinning can be depicted by a cubic model. In this sample, the children with myopia had thinner crystalline lenses than the children with emmetropia of the same age.
This article provides the first longitudinal evidence that the crystalline lens thins during the period of coordinated ocular growth between the ages of 6 and 10 years. Further, it shows that lens thickness is associated with refractive error. Thinner crystalline lenses in children with myopia may result from one of two underlying mechanisms: Either the crystalline lens exhausts its ability to compensate for axial elongation after undergoing accelerated lens thinning before the onset of myopia, or the crystalline lens in the myopic eye may be thinner throughout childhood, during which it thins at a rate consistent with other refractive errors. If mechanical forces link eye growth to crystalline lens compensation, more complex, visually guided feedback loops may not be needed to explain the normal eye growth that results in emmetropization.
大多数早期研究表明，眼睛的晶状体在一生中持续生长，但也有关于儿童期晶状体变薄的横断面研究结果报道。作者使用横断面和纵向数据研究了儿童期晶状体的厚度。
奥林达近视纵向研究是一项基于社区的学龄儿童正常眼睛生长和近视发展的研究。在1至3年的时间里，对869名6至14岁儿童进行了A超超声晶状体厚度测量分析。
平均而言，6至10岁之间，晶状体的轴向尺寸变薄了近0.2毫米。这种变薄可用三次模型来描述。在这个样本中，近视儿童的晶状体比同年龄正视儿童的晶状体更薄。
本文提供了首个纵向证据，证明晶状体在6至10岁眼睛协调生长期间变薄。此外，研究表明晶状体厚度与屈光不正有关。近视儿童晶状体较薄可能源于两种潜在机制之一：要么晶状体在近视发生前经历加速变薄后，耗尽了其补偿眼轴伸长的能力；要么近视眼的晶状体在整个儿童期可能都较薄，在此期间其变薄速度与其他屈光不正情况一致。如果机械力将眼睛生长与晶状体补偿联系起来，那么可能不需要更复杂的视觉引导反馈回路来解释导致正视化的正常眼睛生长过程。
