THE DEVELOPMENT OF PARAFOVEAL AND MID-PERIPHERAL HUMAN RETINA
THE DEVELOPMENT OF PARAFOVEAL AND MID-PERIPHERAL HUMAN RETINA
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DOI：
10.1016/s0166-4328(05)80191-3
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发表时间：
1992-07-31
影响因子：
2.7
通讯作者：
DRUCKER, D
中科院分区：
文献类型：
--
作者：
HENDRICKSON, A;DRUCKER, D
本文研究了人视网膜黄斑旁(距中心凹1-1.5 mm)和中周部(距中心凹4 mm)的形态发育。在F26周时，在两个视网膜点，所有的层和神经元类型都已经存在。F26周光感受器只有一个不发育的内节，没有外节。36周时，视杆细胞和视锥细胞上都有较短的外节。出生后(P)5-8天，视网膜内层相对成熟。光感受器有拉长的基本轴突，这导致光感受器层比出生前的视网膜变得更厚。在出生时，圆锥体内节不是锥形的，但杆状内节已经达到了2亩-m的成虫宽度。杆状和球果的内外节段均为成虫长度的30-50%。到13个月时，内视网膜和外视网膜都成熟了，由于Henle纤维的伸长，光感受器占视网膜厚度的一半。圆锥体外节伸长到P5岁，杆状外节伸长到P13岁。F26周时，视网膜节位于视杆细胞上，36周时视锥细胞上可见外节。出生时，视网膜内部是成人型的。由于Henle纤维的延长，外丛状层在45个月前变厚。出生时，视杆细胞和视锥细胞的中周内段比黄斑旁视网膜稍长，外段比黄斑旁视网膜长50%。到5岁时，中周杆外段略长于黄斑旁视网膜，此后变化不大。这一解剖学研究发现，周边视杆环视网膜的光感受器发育早于中央视网膜的光感受器，而中央凹旁视网膜的光感受器发育早于中心凹视锥。这表明，在中心凹视锥视觉占优势之前，人类新生儿可能会利用更多的周边视网膜区域来实现某些方面的视觉功能。
The morphological development of parafoveal retina (1-1.5 mm from the foveal center) and the mid-peripheral (4 mm from the foveal center) human retina has been studied from fetal (F) 26 weeks to adulthood. At both retinal points, all layers and neuronal types are present at F26 weeks. In parafovea at F26 weeks photoreceptors have only a rudimentary inner segment and no outer segments. Short outer segments are present on both rods and cones at F36 weeks. By postnatal (P) 5-8 days the inner retina is relatively mature. Photoreceptors have elongated basal axons which cause the photoreceptor layer to become much thicker than in prenatal retina. At birth cone inner segments are untapered, but rod inner segments have already reached their adult width of 2-mu-m. Both rod and cone inner and outer segments are 30-50% of adult length. By 13 months both inner and outer retina are mature appearing, with the photoreceptors accounting for half the retinal thickness due to the elongation of the fibers of Henle. Cone outer segments elongate up to P5 years and rod outer segments to P 13 years. At mid-peripheral or rod-ring retina outer segments are present on rods at F26 weeks and on cones at F36 weeks. At birth the inner retina is adultlike. The outer plexiform layer becomes thicker up to P45 months due to the elongation of fibers of Henle. At birth both rod and cone mid-peripheral inner segments are slightly longer and outer segments are 50 % longer than in parafoveal retina. By P5 years mid-peripheral rod outer segments are slightly longer than in parafoveal retina, and this changes little thereafter. This anatomical study has found that the photoreceptors in peripheral rod-ring retina develop earlier than those in more central retina, and in tum parafoveal photoreceptors develop well in advance of foveal cones. This suggests that human neonates may utilize more peripheral retinal regions for some aspects of visual function before foveal cone vision becomes dominant.