July 2019
Volume 60, Issue 9
Free
ARVO Annual Meeting Abstract  |   July 2019
Putative S cones in macaque identified by phasor analysis of adaptive optics fluorescence lifetime ophthalmoscopy
Author Affiliations & Notes
  • Khang T Huynh
    Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States
    Center for Visual Science, University of Rochester, Rochester, New York, United States
  • Sarah Walters
    The Institute of Optics, University of Rochester, Rochester, New York, United States
    Center for Visual Science, University of Rochester, Rochester, New York, United States
  • Emma K. Foley
    Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States
    Center for Visual Science, University of Rochester, Rochester, New York, United States
  • Keith Parkins
    Center for Visual Science, University of Rochester, Rochester, New York, United States
  • Jennifer J Hunter
    Flaum Eye Institute, University of Rochester, Rochester, New York, United States
    Center for Visual Science, University of Rochester, Rochester, New York, United States
  • Footnotes
    Commercial Relationships   Khang Huynh, None; Sarah Walters, None; Emma Foley, None; Keith Parkins, None; Jennifer Hunter, None
  • Footnotes
    Support  NIH Grants EY022371, EY001319; NSF Grant DGE-1419118; Unrestricted Grant to the University of Rochester Department of Ophthalmology and Special Scholars Award to JJH from Research to Prevent Blindness, New York, New York
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 1778. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Khang T Huynh, Sarah Walters, Emma K. Foley, Keith Parkins, Jennifer J Hunter; Putative S cones in macaque identified by phasor analysis of adaptive optics fluorescence lifetime ophthalmoscopy. Invest. Ophthalmol. Vis. Sci. 2019;60(9):1778.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose : Adaptive optics fluorescence lifetime imaging ophthalmoscopy (AOFLIO) has revealed a difference in fluorescence lifetime between macaque cones and rods, likely due to functional differences. Similarly, S cones are morphologically and functionally disparate from M/L cones and may exhibit different fluorescence lifetimes. We apply phasor analysis to AOFLIO images to study the lifetime signatures of putative S cones, using their increased susceptibility to damage by multiphoton excitation (Schwarz et al. IOVS, in press) for identification.

Methods : Using 730 nm excitation, AOFLIO was performed on ≤1.1 x 1.3° regions in the photoreceptor layer of macaques (3 male, 1 female; 5-9 y.o.; 26 loc.; 4-20° ecc.; 2 min; 3.5 or 7 mW). Two locations were imaged twice at 7 mW: the first preferentially damaged S cones and the second was used only to identify them based on a fluorescence intensity decrease. Phasor analysis was performed by converting the decay trace at each pixel to a Cartesian coordinate (G,S) defined by its real and imaginary Fourier components. To identify two distinct cone populations, cones were masked at 4 locations and a Gaussian mixture model (GMM) analyzed the average (G,S) of each cone.

Results : Across eccentricities and animals, phasor analysis of AOFLIO photoreceptor images produced a characteristic elliptical distribution of phasor coordinates (Fig. 1a-b) with distinct regions corresponding to cones and rods (Fig. 1c-d), confirming our previous work analyzing mean lifetimes. We also observed that cone pixels on the phasor plots appeared to separate into two elliptical distributions in 88% of locations (Fig. 1d). GMM classification of two cone populations resulted in one group corresponding to 11±0.66% of cones, consistent with S cone distribution. In two such locations, this population corresponded to cones subsequently identified as damaged by multiphoton excitation (87% sensitivity, 99% specificity).

Conclusions : By combining AOFLIO and phasor analysis, we identified a subset of cones consistent with S cone distribution and corroborated by their susceptibility to photodamage with multiphoton excitation. We do not know whether the different lifetime signature for putative S cones results from inherent morphological differences or a multiphoton absorption effect. By either mechanism, this approach represents a new way to functionally characterize cone photoreceptors.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

×
×

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.

×