Computational determination of refractive index distribution in the crystalline cones of the compound eye of Antarctic krill (Euphausia superba)
Computational determination of refractive index distribution in the crystalline cones of the compound eye of Antarctic krill (Euphausia superba)
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DOI：
10.1016/j.jtbi.2006.08.001
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发表时间：
2007-01-21
影响因子：
2
通讯作者：
Meyer-Rochow, Victor Benno
中科院分区：
文献类型：
--
作者：
Gal, Jozsef;Miyazaki, Taeko;Meyer-Rochow, Victor Benno
为了了解复眼是如何将光引导到视网膜并形成图像的，我们需要知道晶体锥体中的折射率分布。直接测量折射率需要新鲜的、不固定的组织切片和干涉显微镜的使用，但通常两者都无法实现。利用南极磷虾的眼睛(须鲸的主要食物)，我们开发了一种计算方法，可以在不需要干涉显微镜的情况下，从固定材料的切片上无创地预测可能的折射率分布。我们使用了眼睛的计算机模型，并计算出晶体锥体中最真实的折射率梯度空间分布，这将使眼睛在视网膜上产生清晰的图像。众所周知，动物的视力很好，根据我们的计算，我们预测，对于成年人的眼睛，视锥中心的最大折射率为1.45-1.50，比N-max为1.55时，目标视网膜感受器的角度敏感度和光吸收更好。然而，在屈光结构和视网膜之间空间间隔较窄的青少年中，N-max为1.50-1.55会给出更好的结果。我们的方法可以在不需要新材料和干涉显微镜的情况下确定锥体内最可能的折射率分布，这种方法可以用于研究其他无脊椎动物的眼睛，这些无脊椎动物的眼睛具有良好的分辨率，但由于各种原因不适合或不允许对其屈光组织进行直接折射率测量。(C)2006爱思唯尔有限公司。保留所有权利。
In order to understand how a compound eye channels light to the retina and forms an image, one needs to know the refractive index distribution in the crystalline cones. Direct measurements of the refractive indices require sections of fresh, unfixed tissue and the use of an interference microscope, but frequently neither is available. Using the eye of the Antarctic krill Euphausia superba (the main food of baleen whales) we developed a computational method to predict a likely refractive index distribution non-invasively from sections of fixed material without the need of an interference microscope. We used a computer model of the eye and calculated the most realistic spatial distribution of the refractive index gradient in the crystalline cone that would enable the eye to produce a sharp image on the retina. The animals are known to see well and on the basis of our computations we predict that for the eyes of the adult a maximum refractive index of 1.45-1.50 in the centre of the cone yields a better angular sensitivity and light absorption in a target receptor of the retina than if N-max were 1.55. In juveniles with a narrower spatial separation between dioptric structures and retina, however, an N-max of 1.50-1.55 gives a superior result. Our method to determine the most likely refractive index distribution in the cone without the need of fresh material and an interference microscope could be useful in the study of other invertebrate eyes that are known to possess good resolving power, but for a variety of reasons are not suitable for or will not permit direct refractive index measurements of their dioptric tissues to be taken. (c) 2006 Elsevier Ltd. All rights reserved.