Comparable change in stromal refractive index of cat and human corneas following blue-IRIS

Kaitlin T. Wozniak, Sara M. Gearhart, Daniel E. Savage, Jonathan D. Ellis, Wayne H. Knox, Krystel R. Huxlin

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Blue intratissue refractive index shaping (blue-IRIS) is a method with potential to correct ocular refraction noninvasively in humans. To date, blue-IRIS has only ever been applied to cat corneas and hydrogels. To test the comparability of refractive index change achievable in cat and human tissues, we used blue-IRIS to write identical phase gratings in ex vivo feline and human corneas. Femtosecond pulses (400 nm) were focused ∼300 μm below the epithelial surface of excised cat and human corneas and scanned to write phase gratings with lines ∼1 μm wide, spaced 5 μm apart, using a scan speed of 5 mm/s. Additional cat corneas were used to test writing at 3 and 7 mm/s in order to document speed dependence of the refractive index change magnitude. The first-order diffraction efficiency was immediately measured and used to calculate the refractive index change attained. Our data show that blue-IRIS induces comparable refractive index changes in feline and human corneas, an essential requirement for further developing its use as a clinical vision correction technique.

Original languageEnglish (US)
Article number055007
JournalJournal of biomedical optics
Issue number5
StatePublished - 2017


  • cornea
  • femtosecond
  • refractive
  • stroma

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering


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