PMID- 22254172
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20120313
LR  - 20240507
IS  - 2156-7085 (Electronic)
IS  - 2156-7085 (Linking)
VI  - 3
IP  - 1
DP  - 2012 Jan 1
TI  - Phase-sensitive imaging of the outer retina using optical coherence tomography 
      and adaptive optics.
PG  - 104-24
LID - 10.1364/BOE.3.000104 [doi]
AB  - The cone photoreceptor's outer segment (OS) experiences changes in optical path 
      length, both in response to visible stimuli and as a matter of its daily course 
      of renewal and shedding. These changes are of interest, to quantify function in 
      healthy cells and assess dysfunction in diseased ones. While optical coherence 
      tomography (OCT), combined with adaptive optics (AO), has permitted unprecedented 
      three-dimensional resolution in the living retina, it has not generally been able 
      to measure these OS dynamics, whose scale is smaller than OCT's axial resolution 
      of a few microns. A possible solution is to take advantage of the phase 
      information encoded in the OCT signal. Phase-sensitive implementations of 
      spectral-domain optical coherence tomography (SD-OCT) have been demonstrated, 
      capable of resolving sample axial displacements much smaller than the imaging 
      wavelength, but these have been limited to ex vivo samples. In this paper we 
      present a novel technique for retrieving phase information from OCT volumes of 
      the outer retina. The key component of our technique is quantification of phase 
      differences within the retina. We provide a quantitative analysis of such phase 
      information and show that-when combined with appropriate methods for filtering 
      and unwrapping-it can improve the sensitivity to OS length change by more than an 
      order of magnitude, down to 45 nm, slightly thicker than a single OS disc. We 
      further show that phase sensitivity drops off with retinal eccentricity, and that 
      the best location for phase imaging is close to the fovea. We apply the technique 
      to the measurement of sub-resolution changes in the OS over matters of hours. 
      Using custom software for registration and tracking, these microscopic changes 
      are monitored in hundreds of cones over time. In two subjects, the OS was found 
      to have average elongation rates of 150 nm/hr, values which agree with our 
      previous findings.
CI  - 2011 Optical Society of America
FAU - Jonnal, Ravi S
AU  - Jonnal RS
AD  - Program in Vision Science, Indiana University, 800 East Atwater Avenue, 
      Bloomington, IN 47405, USA. rjonnal@indiana.edu
FAU - Kocaoglu, Omer P
AU  - Kocaoglu OP
FAU - Wang, Qiang
AU  - Wang Q
FAU - Lee, Sangyeol
AU  - Lee S
FAU - Miller, Donald T
AU  - Miller DT
LA  - eng
GR  - P30 EY019008/EY/NEI NIH HHS/United States
GR  - R01 EY014743/EY/NEI NIH HHS/United States
GR  - R01 EY018339/EY/NEI NIH HHS/United States
GR  - R01 EY018339-05/EY/NEI NIH HHS/United States
PT  - Journal Article
DEP - 20111213
PL  - United States
TA  - Biomed Opt Express
JT  - Biomedical optics express
JID - 101540630
PMC - PMC3255329
OTO - NOTNLM
OT  - (010.1080) Active or adaptive optics
OT  - (100.3175) Interferometric imaging
OT  - (100.5070) Phase retrieval
OT  - (100.5088) Phase unwrapping
OT  - (170.0180) Microscopy
OT  - (170.4500) Optical coherence tomography
OT  - (330.5310) Vision - photoreceptors
EDAT- 2012/01/19 06:00
MHDA- 2012/01/19 06:01
PMCR- 2011/12/13
CRDT- 2012/01/19 06:00
PHST- 2011/09/26 00:00 [received]
PHST- 2011/11/29 00:00 [revised]
PHST- 2011/12/02 00:00 [accepted]
PHST- 2012/01/19 06:00 [entrez]
PHST- 2012/01/19 06:00 [pubmed]
PHST- 2012/01/19 06:01 [medline]
PHST- 2011/12/13 00:00 [pmc-release]
AID - 155278 [pii]
AID - 10.1364/BOE.3.000104 [doi]
PST - ppublish
SO  - Biomed Opt Express. 2012 Jan 1;3(1):104-24. doi: 10.1364/BOE.3.000104. Epub 2011 
      Dec 13.