June 2022
Volume 63, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2022
Phase imaging in the inner retina
Author Affiliations & Notes
  • Mircea Mujat
    Biomedical Optics Technologies, Physical Sciences Inc, Andover, Massachusetts, United States
  • Ankit Patel
    Biomedical Optics Technologies, Physical Sciences Inc, Andover, Massachusetts, United States
  • John Grimble
    Biomedical Optics Technologies, Physical Sciences Inc, Andover, Massachusetts, United States
  • Nicusor Iftimia
    Biomedical Optics Technologies, Physical Sciences Inc, Andover, Massachusetts, United States
  • Footnotes
    Commercial Relationships   Mircea Mujat Physical Sciences Inc, Code E (Employment); Ankit Patel Physical Sciences Inc, Code E (Employment); John Grimble Physical Sciences Inc, Code E (Employment); Nicusor Iftimia Physical Sciences Inc, Code E (Employment)
  • Footnotes
    Support  NIH grant 5R44EY023481
Investigative Ophthalmology & Visual Science June 2022, Vol.63, 1482. doi:
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Mircea Mujat, Ankit Patel, John Grimble, Nicusor Iftimia; Phase imaging in the inner retina. Invest. Ophthalmol. Vis. Sci. 2022;63(7):1482.

      Download citation file:

      © ARVO (1962-2015); The Authors (2016-present)

  • Supplements

Purpose : The purpose of the current study was to identify new contrast mechanisms that can reveal retinal structures not visible with other methods. Simultaneous multi-channels offset AO-SLO imaging provides isotropic images of retinal microstructures free of directionality artifacts and enables phase imaging in the living eye with enhanced visualization contrast.

Methods : We developed a new detection scheme with an arrangement of light collecting fibers that provides isotropic imaging while retaining all the advantages of offset aperture and split-detector imaging. Four optical fibers are arranged as a compact bundle and all offset images are collected simultaneously with the confocal image. The two orthogonal offset pairs provide the split-detector imaging in orthogonal directions removing the directionality disadvantage of other techniques. Oblique back-illumination has been used in microscopy to reveal phase objects that are not visible in confocal microscopy. Split-detection analysis, sometimes called differential phase contrast, is interpreted as phase derivative. One can reconstruct the phase from orthogonal phase derivatives or directly calculate the phase gradient.

Results : Split-detection analysis is performed using multiple combinations of the four offset images. Two orthogonal split images are generated for orthogonal fiber pairs 1-3 and 2-4 (A and B in Fig. 1). Two additional split images (C and D) are obtained by adding first adjacent fibers (for example 1+2 and 3+4) and then performing subtraction divided by sum of the two sums. Therefore we obtain four split images: horizontal, vertical, and two diagonal (+/-45deg). They highlight structural edges such as blood vessel walls along different directions given the directionality associated with the split direction. The phase (P) and the phase gradient (PG) images are obtained from either one of these two pairs of split images. In addition, the mean of the four split standard deviation images (STD) isotropically highlights the blood flow vasculature. Circled areas in Fig. 1 highlight local microstructures that have no blood flow associated with them (not visible in the STD image). They could potentially be microglia based on their location in the proximity of the blood vessels.

Conclusions : The multi-aperture AO-SLO imaging based on simultaneous acquisition of multiple offset aperture images provides an improved, isotropic image in the inner retina free of single offset-axis directionality artifacts.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.



This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.