IRIS – Indiana Retinal Image Simulator

IRIS is a collaborate effect of many years of work of numerous researchers initiated and led by prof. Larry Thibos at Indiana University (and formerly known as FOC – Fourier Optics Calculator). Many of its features have been used throughout the years in numerous iconic scientific publications in the field of physiological optics.^1,2,3

IRIS is now superseded by IWA (Indiana Wavefront Analyzer) and is no longer actively developed. There will be no new versions. If IRIS works for you, but your research or application requires features or analyses not included in IRIS, please contact us to discuss a potential collaboration.

Current version (Development v. 0.94): New features – see changelog.txt for details. Download PC Version (230 Mb .exe), MAC Version (coming soon).

IRIS is mainly a research tool written in Matlab, but the Authors hope that it will also be of interest to students from fields like physiological optics, vision, optometry, and others. We hope that a simple user interface and accurate graphics can vividly illustrate the characteristics of ocular aberrations and their impact on retinal image quality through point spread functions and retinal simulations.

You are free to use this software for research and academic purposes under the condition that you provide the following reference:

Jaskulski M, Thibos L, Bradley A, Kollbaum P, et al. IRIS – Indiana Retinal Image Simulator. 2019; https://blogs.iu.edu/corl/iris.

This software is released under the following license:
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License
Please see https://creativecommons.org/licenses/by-nc-nd/4.0/ for more information.

I. Requirements

1. A modern PC or MacPC or Mac with a display with at least 1600 x 900 pixels (1920 x 1080 recommended).
2. At least 1 Gb of free hard disk space
3. Certain understanding of optical aberrations, wavefronts and optics.

II. Installation

1. Download the IRIS installation executable (.exe) into a folder of your choice.
2. Run the installer. It contains the required Matlab Runtime Dependencies (approximately 800 Mb) which will be downloaded alongside IRIS.
3. Follow the on-screen instructions to complete the installation
4. Navigate to the folder where you extracted IRIS and run the program by executing “IRIS”.

III. Features

1. Input data formats:

   • F4, F6, F8, F10 – Wavefront Sciences COAS.
   • WF – Johnson & Johnson iDesign.
   • DAT – ImagineOptic HASO.
   • TXT – ImagineOptic IRX3.
   • CSV – Nidek OPD Scan III.
   • MAT – IRIS’s own, previously saved data.
   • Manual data entry.

2. Output data formats:

   IRIS allows users to save certain results of carried-out analyses either as images (PNG, JPG) or as plain-text data copied to the clipboard which can then be pasted into Excel or any other program. Additionally IRIS can save complete analysis results into MAT files.

3. Analysis capabilities

   Work with IRIS starts by inputting ocular aberrations espressed as Zernike coefficients using one of the supported data formats. Subsequently the following capabilities become available:

   • Computing optometric parameters: cylinder, sphere, axis, power vectors, minRMS, paraxial, MTR spherical equivalents, etc.
   • Performing both single and through-Zernike analyses of image quality (IQ), in particular through-focus analyses.
   • Computing Fourier and geometrical optics Point-Spread-Functions (PSFs).
   • Evaluating IQ with numerous objective refraction metrics.
   • Performing polychromatic simulations which take into account the longitudinal chromatic aberration (LCA), human spectral sensitivity curve (Vλ) and spectral power distribution (SPD) of a source.
   • Simulate effects of different pupil shapes and sizes and effects of pupil masking (for example due to cataract).
   • Computing and plotting detailed wavefront-derived functions such as vergence, curvature and slope and also the modulation transfer function (MTF).
   • and more… please refer to the changelog.txt for more information.

4. Example Screen Shots

   

   

   

   

5. Known Bugs and Future Development

   Due to its complexity and numerous possible analysis configurations there are still some loose ends to tie up in IRIS v. 0.9. These are mostly confined to the Image Quality Metrics analysis window (accessible from the charts icon in the top right corner of the screen). If you experience any errors or inconsistencies related to the image quality metrics computation, please know that we’re aware of it. Furthermore, several IQ metrics, in particular the VSOTF need to be revised. At the moment the recommended metrics to use are the SR, VSX, ISVA, and LiB. The development of IRIS will conclude with version 1.0 as we are focusing on a new piece of software, called the Indiana Wavefront Analyzer. It will pick up from where IRIS left, adding zonal wavefront reconstruction features.

6. Change Log (Version 0.94)

   The most recent changes to the program can always be found in the “changelog.txt” file. Here are the most recent changes:
   – Added support for J&J iDesign WF files.
   – Fixed support for COAS Fn files in Batch Mode.
   – Validated and improved the frequency scaling of PSF’s and MTF’s in accordance with the diffraction limit,
   – New feature in the Launcher; “add wavefront”. Any two-dimensional wavefront can now be added on top of the Zernike-described wavefront to create composite eye models.
   – Interface tweaks and improvements.

7. Acknowledgements

   Thank you to contributors: Jos Rozema (statistical wavefront generator,⁴ and testing for bugs), Sowmya Ravikumar (polychromatic PSF algorithms),³ Linda Lundström (Zernike rescaling algorithms),⁵ and others.
   Special thank you to: Norberto López Gil, Pete Kollbaum, D. Robert Iskander, Iván Marin-Franch, José Manuel Gonzalez-Meijome.
   Very special thank you to: Arthur Bradley, who’s not authored any code but envisioned, tested or otherwise dabbled in most of it.

8. References

   1. Metrics of optical quality derived from wave aberrations predict visual performance. Marsack JD, Thibos LN, Applegate RA. J Vis. 2004 Apr 23;4(4):322-8.
   2. Accuracy and precision of objective refraction from wavefront aberrations. Thibos LN, Hong X, Bradley A, Applegate RA. J Vis. 2004 Apr 23;4(4):329-51.
   3. Calculation of retinal image quality for polychromatic light. Ravikumar S, Thibos LN, Bradley A. J Opt Soc Am A Opt Image Sci Vis. 2008 Oct;25(10):2395-407.
   4. SyntEyes: A Higher-Order Statistical Eye Model for Healthy Eyes. Jos J. Rozema, Pablo Rodriguez, Rafael Navarro, Marie-José Tassignon; Invest. Ophthalmol. Vis. Sci. 2016;57(2):683-691. doi: 10.1167/iovs.15-18067.
   5. Transformation of Zernike coefficients: scaled, translated, and rotated wavefronts with circular and elliptical pupils. Linda Lundström and Peter Unsbo. J. Opt. Soc. Am. A 24, 569-577 (2007)

9. Donate

   If you find IRIS useful and would like to support its development you can donate. Suggested donations: Student $1. Researcher $50. Industry $200. Coffee $0.50. Coffee is fine.

   

10. Contact and Support

    IRIS is available to download for free exclusively via the IU Clinical Optics Research Lab website (https://blogs.iu.edu/corl/iris). If you have questions or feedback (which is very welcome!) please use feedback form below rather than trying to reach the Authors directly. The exception would be research collaborations – if you are a researcher or a Masters/PhD-degree student and wish to collaborate with us and use IRIS, feel free to contact us.

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11. Disclaimer

    THIS SOFTWARE IS PROVIDED “AS IS” AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.