欧洲研究人员发现一种神奇“四眼鱼”，它的其中一对眼睛拥有类似反射镜的物质，可以帮助它在深海中更好地看清天敌所在位置。
这项刊登在《当代生物学》杂志上的研究发现，“四眼鱼”其中一对眼睛中含有晶状体，另一对朝下的眼睛中含有一种与反射镜功能相同的物质。光线进入这对眼睛后会被反射到视网膜上，帮助“四眼鱼”看清它下方的物体。
英国布里斯托尔大学教授尤利安·帕特里奇说，黑暗中，带有“反射镜”的眼睛看东西更有效率。因为当光线经过时，含有晶状体的眼睛吸收的光线有限，而“反射镜”能够把更多的光线反射到视网膜上。这样，当海中天敌在黑暗中经过时，“反射镜”能更有效地预警“四眼鱼”。
英国《泰晤士报》8日援引科学家的话说，“四眼鱼”是迄今唯一一种眼睛中带有“反射镜”的脊椎动物。
“在脊椎动物近5亿年的进化过程中，数以千计的动物出生、死亡，”帕特里奇说，“这种‘四眼鱼’的发现解答了一个根本的视觉问题，即如何利用‘反射镜’在视网膜上成像。这是一种神奇的动物，在脊椎动物中绝对独一无二。眼睛中的‘反射镜’可以帮助它形成更鲜明图像。”
早在120年前，人们就已经得知这种“四眼鱼”的存在，但一直不知道它眼睛的奥妙，直到德国蒂宾根大学教授汉斯—约阿希姆·瓦格纳18个月前捕获一只并首次展开研究。（生物谷Bioon.com）
生物谷推荐原始出处：
Current Biology, 24 December 2008 doi:10.1016/j.cub.2008.11.061
A Novel Vertebrate Eye Using Both Refractive and Reflective Optics
Hans-Joachim Wagner1,Ron H. Douglas2,,,Tamara M. Frank3,Nicholas W. Roberts4,6andJulian C. Partridge5
1 Anatomisches Institut, Universit?t Tübingen, ?sterbergstrasse 3, 72074 Tübingen, Germany
2 Henry Welcome Laboratory for Vision Sciences, Department of Optometry and Visual Science, City University, Northampton Square, London EC1V 0HB, UK
3 Center for Ocean Exploration and Deep-Sea Research, Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 U.S. 1 N, Fort Pierce, FL 34946, USA
4 The Photon Science Institute, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
5 School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
6 Present address: Department of Biology, Queens University, Kingston, ONK7L 3N6, Canada
Sunlight is attenuated rapidly in the ocean, resulting in little visually useful light reaching deeper than 1000 m in even the clearest water [1]. To maximize sensitivity to the relatively brighter downwelling sunlight, to view the silhouette of animals above them, and to increase the binocular overlap of their eyes, many mesopelagic animals have developed upward-pointing tubular eyes [2,3,4]. However, these sacrifice the ability to detect bioluminescent [5] and reflective objects in other directions. Thus, some mesopelagic fish with tubular eyes extend their visual fields laterally and/or ventrally by lensless ocular diverticula, which are thought to provide unfocused images, allowing only simple detection of objects, with little spatial resolution [2,3,4]. Here, we show that a medial mirror within the ventrally facing ocular diverticulum of the spookfish, Dolichopteryx longipes, consisting of a multilayer stack derived from a retinal tapetum, is used to reflect light onto a lateral retina. The reflective plates are not orientated parallel to the surface of the mirror. Instead, plate angles change progressively around the mirror, and computer modeling indicates that this provides a well-focused image. This is the first report of an ocular image being formed in a vertebrate eye by a mirror.
