NONLINEAR PROJECTION OF RETINAL IMAGE IN A WIDE-ANGLE SCHEMATIC EYE
NONLINEAR PROJECTION OF RETINAL IMAGE IN A WIDE-ANGLE SCHEMATIC EYE
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DOI：
10.1136/bjo.58.8.709
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发表时间：
1974-01-01
影响因子：
4.1
通讯作者：
FOWLER, CW
中科院分区：
文献类型：
--
作者：
DRASDO, N;FOWLER, CW
方法从综述文章(Duke-Elder和Wybar，I96I；Duke-Elder和Abrams，I970)和个别报告(Prechtel和Wesley，I970；Mandell和St Helen，I97I)中收集数据，试图为简化的图眼制定适当的规范，并发现这在很大程度上近似于Stine(1934)在广角模型中使用的Cowan(I928)早期的近轴数据。然而，似乎有必要做出一些根本性的修改。积累的角膜地形图数据支持了Helmholtz(1866)的建议，即角膜的形状是由椭球体近似模拟的。这样的曲面可以用顶端半径和偏心度来表示。Prechtel和Wesley(1970)基于150只眼睛的数据显示了这一参数的明显单峰趋势，这进一步得到Mandell和St Helen(I97I)对8只人眼的更详细的发现的支持。在保留根尖半径7~8 mm的情况下，取e=o-。这导致了由简单方程定义的椭球体：X=124336-2y‘t也被认为是修改视网膜边缘的数据所必需的。这一定位与Duke-Elder和Wybar(I96I)引用的锯缘缘距离和盲肠部与功能性视网膜交界处的解剖学值一致。由此产生的视网膜边缘的垂直和水平不对称如表所示，在图中所示的光学几何图中也很明显。I.椭圆在任何一点的斜率可能是
MethodAssembled data from review articles (Duke-Elder and Wybar, I96I; Duke-Elder and Abrams, I970) and individual reports (Prechtel and Wesley, I970; Mandell and St Helen, I97I) were considered in an attempt to formulate an adequate specification for a simplified schematic eye, and this was found for the most part to approximate to the earlier paraxial data of Cowan (I928) which was utilized in a wide-angle model by Stine (1934). It appeared necessary, however, to make some fundamental modifications. Accumulating data on corneal topography has supported the suggestion of Helmholtz (i 866) that the shape of the cornea is closely simulated by an ellipsoid. Such a surface can be specified in terms of an apical radius andan'e'value, or eccentricity. The data of Prechtel and Wesley (1970), based on 150 eyes, show a clear unimodal tendency of this parameter which is further supported by the more detailedfindings of Mandell and St Helen (I97I) on eight human eyes. The peak value from these papers was taken as e= o-, while retaining the apical radius of 7-8 mm. which results in the ellipsoid defined by the simple equation: x= l243 36-2y'It was also considered necessary to modify the data on the margin of the retina. This was located in accordance with the anatomical values quoted by Duke-Elder and Wybar (I96I) on limbal distance of the ora serrata and the junction of the pars caeca with the functional retina. The resultant vertical and horizontal asymmetry of the retinal margin is shown in the Table, and is apparent also in the diagram ofthe optical geometry shown in Fig. i. The slope of the ellipse at any one point could be