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A Novel Vertebrate Eye Using Both Refractive and Reflective Optics
Current Biology
  • Hans-Joachim Wagner, Universität Tubingen - Germany
  • Ron H. Douglas, City University - London, United Kingdom
  • Tamara M. Frank, Harbor Branch Oceanographic Institution
  • Nicholas W. Roberts, University of Manchester - United Kingdom
  • Julian C. Partridge, University of Bristol - United Kingdom
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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 [2-4]. 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 [2-4]. 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.

©2009 Elsevier Ltd. All rights reserved.

Additional Comments
NSF grant #: IBN-0343871
Citation Information
Hans-Joachim Wagner, Ron H. Douglas, Tamara M. Frank, Nicholas W. Roberts, et al.. "A Novel Vertebrate Eye Using Both Refractive and Reflective Optics" Current Biology Vol. 19 Iss. 2 (2009) p. 108 - 114 ISSN: 0960-9822
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