The Indiana Adaptive Optics SLO

Project Director:  Stephen A. Burns, Ph.D. (Research Home Page)

The Indiana Adaptive Optics Scanning Laser Ophthalmoscope is being developed under an NIH Bioengineering Partnership (NEI RO1 EY14375 – “Adaptive Optics Instrumentation for Advanced Ophthalmic Imaging” ).   Our center is working on combining high resolution SLO technology with both scattered light imaging, polarization state imaging, and image stabilization (See Reference List)

A Scanning Laser Ophthalmoscope (SLO) is a type of confocal microscope which is optimized for imaging the eye.  Currently our system can image multiple layers of the retina in real time.  This provides exquisite images of the cells of the retina.  The figure to the right shows images of the cone photoreceptors of a human eye.  The fovea is just off-screen in the upper left corner of the figure.  Here we can clearly see the increasing size of the cone photoreceptors with increasing distance from the fovea.  The scale bar indicates a retinal size of 50 microns.  Below we show a montage with a more extended view of the normal fovea. 

The First figure below is a picture of the instrument.  Like most adaptive optics systems for retinal imaging, it consists of a wavefront sensor, a wavefront correctors, and an imaging subsystem.  We are working with Daniel Ferguson and Daniel Hammer to improve the eye tracker/ stabilzer, but already we can stabilizer down to about 8 microns (on average).  This allows distortion free measurements of the retina, even during small saccades. 

 

 

 

Visualizing the Smallest Capillaries

We are able to look at blood flow dynamically (see the new ARVO presentation!) as well as produce structural images of the smallest calillaries as seen below).

Foveal Cone Mosaic can be built up using montaging techniques that are potentiated by the retinal tracking and stabilization.  We have an example of in process work on computing cone packing density over wide regions of retinal at http://www.opt.indiana.edu/people/faculty/burns/CenterForOphthalmicImaging/example_of_automated_labeling_of.htm

 

 

 

 

 

 

 

 

Working with Charles Lin at MGH we have helped to generate the first AO Images from a Mouse Eye by Dave Biss (see papers below).

   Polarization Sensitive AOSLO

We have also developed techniques to look at the Stokes Vector of microscopic structures in the retina.  The image below shows that the cone photoreceptors preserve polarization (they are bright in the central degree of Polarization Image, and dark in the Depolarization Image (center and right respectively).

Adaptive Optics Optical Coherence Tomograpy

We have now integrated and OCT into the AOSLO.  This allows us to compare the excellent en face images available with the AOSLO, to obtain accurate depth profiles.

 

 

 

 

 

 

 

Relevant Publications

  1. Burns, SA, Marcos, S, Elsner, AE, Bara, S, “Contrast Improvement for Confocal Retinal Imaging Using Phase Correcting Plates”  Optics Letters. 27: 400-402, 2002.(full text)
  2. Burns, SA, Elsner, AE, Mellem-Kiraila, MB, and Simmons, RB, Improved Contrast of Subretinal Structures using Polarization Analysis, Investigative Ophthalmology and Visual Science 44(9): 4061-8., 2003.(full text)
  3. Webb, RH, Albanese, MJ, Zhou, Y, Bifano, T and Burns, SA “A stroke amplifier for deformable mirrors” Applied Optics 43(28), 5330-5333 , 2004 (full text)
  4. Ferguson, RD. Hammer, DX, Elsner, AE, Webb, RH, Burns, SA, Weiter, JJ. Wide-field retinal hemodynamic imaging with the tracking scanning laser ophthalmoscope. Optics Express, 12, 5198-5208, 2004.  (on-line)
  5. Mellem-Kairala, MB, Elsner,AE, Weber, A, Simmons,RB, Burns, SA, “Improved contrast of peripapillary hyperpigmentation using polarization analysis”, Investigative Ophthalmology & Visual Science 46(3): 1099-1106, 2005.
  6. Prieto, P, McLellan, J.S., and Burns, S.A. Investigating The Light Absorption In A Single Pass Through The Photoreceptor Layer By Means Of The Lipofuscin Fluorescence. Vision Research 45 (15): 1957-1965, 2005 (full text)
  7. Ferguson, RD, Hammer,DX,  Bigelow CD, Iftimia , NV, Ustun te, Burns, SA, Elsner, AE, Williams, DR, (2006) Tracking adaptive optics scanning laser ophthalmoscope, Proceeding, SPIE.
  8. Hammer,DX, Ferguson, RD,  Bigelow CD, Iftimia , NV, Ustun te, Burns, SA, "Adaptive optics scanning laser ophthalmoscope for stabilized retinal imaging", Opt. Express 14, 3354-3367 (2006)
  9. Biss, D, Sumorok, D, Burns, SA, Webb RH, Zhou Y, Bifano, T, Veilleux I, Zamiri P, and Lin C. “In vivo flourescent imaging of the mouse retina using adaptive optics” Optics Letters  659-661 (2007)
  10. Burns, SA, Tumbar R, Elsner AE, Ferguson RD, Hammer DX “Large Field of View, Modular, Stabilized, Adaptive-Optics-Based Scanning Laser Ophthalmoscope” . J. Opt. Soc Amer,  JOSA A, 1313-1326 (2007).
  11. Hammer,DX, Iftimia , N, Bigelow CD, Ustun TE, Bloom B, Ferguson, RD, Burns, SA, (2007) High resolution retinal imaging with a compact adaptive optics spectral domain optical coherence tomography system Proceeding, SPIE.
  12. Song, H, Zhao, Y, Chui, Y, Qi X, Burns, SA, Stokes Vector Analysis of Adaptive Optics Images of the Retina, Optics Letters, 33, 137-140. (2008)
  13. Chui, Y, Song, H, Burns, SA, “Individual variations in human cone photoreceptor packing density: variations with refractive error.” Investigative Ophthalmology and Vision Science First published on Jun 14, 2008 as doi: doi:10.1167/iovs.08-2135
  14. Zhong, Z, Petrig, BL, Qi X and Burns SA “In vivo measurement of erythrocyte velocity and retinal blood flow using adaptive optics scanning laser ophthalmoscopy” Optics Express Vol. 16, Issue 17, pp. 12746-12756 (2008)
  15.  Zou, W, Qi, X, Burns, SA, “Wavefront aberration sorting and correction for dual-deformable-mirror adaptive optics system” Optics Letters, Vol. 33, Issue 22, pp. 2602-2604, 2008
  16. Chui, T. Y. P., H. Song, Burns, SA "Individual variations in human cone photoreceptor packing density" JOSA A 25:3021-3029 ,2008.
  17. Chui, TYP, Thibos, LN, Bradley, A, Burns, SA " The mechanism of vision loss associated with a cotton-wool spot" in press, Vision Research
  18. Zou, W, Burns, SA, "High-accuracy wavefront control for retinal imaging with Adaptive-Influence-Matrix Adaptive Optics" in press Optics Express.

     

MORE Pictures (large mosaics are available through the experimental interface for Interactive Science Publishing, a joint project of the Optical Society of America and The National Library of Medicine- our paper is here.