The Dual Functional Reflecting Iris of the Zebrafish

Dvir Gur, Jan David Nicolas, Vlad Brumfeld, Omri Bar-Elli, Dan Oron, Gil Levkowitz

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Many marine organisms have evolved a reflective iris to prevent unfocused light from reaching the retina. The fish iris has a dual function, both to camouflage the eye and serving as a light barrier. Yet, the physical mechanism that enables this dual functionality and the benefits of using a reflective iris have remained unclear. Using synchrotron microfocused diffraction, cryo-scanning electron microscopy imaging, and optical analyses on zebrafish at different stages of development, it is shown that the complex optical response of the iris is facilitated by the development of high-order organization of multilayered guanine-based crystal reflectors and pigments. It is further demonstrated how the efficient light reflector is established during development to allow the optical functionality of the eye, already at early developmental stages.

Original languageEnglish
Article number1800338
JournalAdvanced Science
Issue number8
Publication statusPublished - Aug 2018


  • biomineralization
  • guanine crystals
  • iridophores
  • photonic crystals
  • vision
  • zebrafish development

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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