Human vision starts when photoreceptors collect and respond to light. Normal photoreceptor function and its support from the underlying retinal pigment epithelium (RPE) are essential for normal vision, yet techniques to assess these processes in vivo are limited. Current optical and electrophysiological techniques have limited spatial resolution and sensitivity, and target only specific functional processes. New optical modalities that are rapid, specific, and noninvasive hold the promise of greatly expanding our capability to monitor more accurately and completely the photoreceptor RPE complex. We will use adaptive optics (AO) and optical coherence tomography (OCT) to achieve unprecedented 3D resolution for studying physiological mechanisms at the cellular level in the photoreceptor and RPE layers. Further improvements will be realized using AOOCT in conjunction with an exquisitely sensitive phase technique that we have developed and that measures optical length changes as small as 45nm.This is slightly thicker than a single cone outer segment (OS) disc and nearly 100times better than the axial resolution of ultra high resolution OCT.
The specific aims are to: (1) Determine the physical parameters that control light capture in photoreceptors;(2) Evaluate properties of light scatter in photoreceptors;and (3) Evaluate properties of light scatter in RPE.

Public Health Relevance

The long term goal of this research is to establish high-resolution imaging methods that probe structure and function of the retina at the cellular scale. The target cells in this study are photoreceptors and retinal pigment epithelial cells, both associated with the capture of light and the first step in seeing. As disease starts at the cellula and molecular levels, the ability to study these pathological disruptions at the single cell level and in patients promises improvements in early detection and treatment monitoring of some of the most blinding diseases in the world.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
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Special Emphasis Panel (NOIT)
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Neuhold, Lisa
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Indiana University Bloomington
Schools of Optometry/Ophthalmol
United States
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Kocaoglu, Omer P; Ferguson, R Daniel; Jonnal, Ravi S et al. (2014) Adaptive optics optical coherence tomography with dynamic retinal tracking. Biomed Opt Express 5:2262-84
Jonnal, Ravi S; Kocaoglu, Omer P; Wang, Qiang et al. (2012) Phase-sensitive imaging of the outer retina using optical coherence tomography and adaptive optics. Biomed Opt Express 3:104-24
Wang, Qiang; Kocaoglu, Omer P; Cense, Barry et al. (2011) Imaging retinal capillaries using ultrahigh-resolution optical coherence tomography and adaptive optics. Invest Ophthalmol Vis Sci 52:6292-9
Kocaoglu, Omer P; Cense, Barry; Jonnal, Ravi S et al. (2011) Imaging retinal nerve fiber bundles using optical coherence tomography with adaptive optics. Vision Res 51:1835-44
Kocaoglu, Omer P; Lee, Sangyeol; Jonnal, Ravi S et al. (2011) Imaging cone photoreceptors in three dimensions and in time using ultrahigh resolution optical coherence tomography with adaptive optics. Biomed Opt Express 2:748-63
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Jonnal, Ravi S; Besecker, Jason R; Derby, Jack C et al. (2010) Imaging outer segment renewal in living human cone photoreceptors. Opt Express 18:5257-70
Gao, Weihua; Jonnal, Ravi S; Cense, Barry et al. (2009) Measuring directionality of the retinal reflection with a Shack-Hartmann wavefront sensor. Opt Express 17:23085-97
Cense, Barry; Koperda, Erik; Brown, Jeffrey M et al. (2009) Volumetric retinal imaging with ultrahigh-resolution spectral-domain optical coherence tomography and adaptive optics using two broadband light sources. Opt Express 17:4095-111
Cense, Barry; Gao, Weihua; Brown, Jeffrey M et al. (2009) Retinal imaging with polarization-sensitive optical coherence tomography and adaptive optics. Opt Express 17:21634-51

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