title: First demonstration of ocular refractive change using blue-IRIS in live cats.
abstract: OBJECTIVE
  To determine the efficacy of intratissue refractive index shaping (IRIS) using 400-nm femtosecond laser pulses (blue light) for writing refractive structures directly into live cat corneas in vivo, and to assess the longevity of these structures in the eyes of living cats.
  
  
  METHODS
  Four eyes from two adult cats underwent Blue-IRIS. Light at 400 nm with 100-femtosecond (fs) pulses were tightly focused into the corneal stroma of each eye at an 80-MHz repetition rate. These pulses locally increased the refractive index of the corneal stroma via an endogenous, two-photon absorption process and were used to inscribe three-layered, gradient index patterns into the cat corneas. The optical effects of the patterns were then tracked using optical coherence tomography (OCT) and Shack-Hartmann wavefront sensing.
  
  
  RESULTS
  Blue-IRIS patterns locally changed ocular cylinder by -1.4 ± 0.3 diopters (D), defocus by -2.0 ± 0.5 D, and higher-order root mean square (HORMS) by 0.31 ± 0.04 μm at 1 month post-IRIS, without significant changes in corneal thickness or curvature. Refractive changes were maintained for the duration they were tracked, 12 months post-IRIS in one eye, and just more than 3 months in the remaining three eyes.
  
  
  CONCLUSIONS
  Blue-IRIS can be used to inscribe refractive structures into live cat cornea in vivo that are stable for at least 12 months, and are not associated with significant alterations in corneal thicknesses or radii of curvature. This result is a critical step toward establishing Blue-IRIS as a promising technique for noninvasive vision correction.
authors.affiliation: The Institute of Optics, University of Rochester, Rochester, New York, United States Center for Visual Science, University of Rochester, Rochester, New York, United States.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Savage
authors.affiliation: The Institute of Optics, University of Rochester, Rochester, New York, United States.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Brooks
authors.affiliation: Flaum Eye Institute, University of Rochester, Rochester, New York, United States.
authors.forename: Margaret
authors.initials: M
authors.lastname: DeMagistris
authors.affiliation: The Institute of Optics, University of Rochester, Rochester, New York, United States.
authors.forename: Lisen
authors.initials: L
authors.lastname: Xu
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, New York, United States Flaum Eye Institute, University of Rochester, Rochester, New York, United States.
authors.forename: Scott
authors.initials: S
authors.lastname: MacRae
authors.affiliation: The Institute of Optics, University of Rochester, Rochester, New York, United States Department of Mechanical Engineering, University of Rochester, Rochester, New York, United States.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Ellis
authors.affiliation: The Institute of Optics, University of Rochester, Rochester, New York, United States Center for Visual Science, University of Rochester, Rochester, New York, United States.
authors.forename: Wayne H
authors.initials: WH
authors.lastname: Knox
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, New York, United States Flaum Eye Institute, University of Rochester, Rochester, New York, United States.
authors.forename: Krystel R
authors.initials: KR
authors.lastname: Huxlin
mesh_terms: D057128:Aberrometry; D000818:Animals; D002415:Cats; D003315:Cornea / Q000033:anatomy & histology; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000502:physiology / Q000601:surgery*; D048988:Corneal Surgery, Laser / Q000379:methods*; D019781:Corneal Topography / Q000379:methods; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D012029:Refraction, Ocular / Q000502:physiology*; D041623:Tomography, Optical Coherence
keywords: IRIS; femtosecond; refractive index