Document Detail


Noninvasive visualization and analysis of parafoveal capillaries in humans.
MedLine Citation:
PMID:  19907024     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: To demonstrate a noninvasive method to visualize and analyze the parafoveal capillary network in humans.
METHODS: An adaptive optics scanning laser ophthalmoscope was used to acquire high resolution retinal videos on human subjects. Video processing tools that enhance motion contrast were developed and applied to the videos to generate montages of parafoveal retinal capillaries. The capillary network and foveal avascular zone (FAZ) were extracted using video and image analysis algorithms. The capillary densities in the zone immediately outside the FAZ were calculated and the variation in density as a function of direction was investigated. Extracted FAZ geometries were used to calculate area and effective diameters. The authors also compared their method against fluorescein angiography (FA) for one subject.
RESULTS: The parafoveal capillaries were clearly visible when the motion contrast in noninvasive videos was enhanced. There was a marked improvement in the contrast of the parafoveal capillaries when compared to the unprocessed videos. The average FAZ area was 0.323 mm(2), with an average effective diameter of 633 microm. There was no variation in capillary density near the FAZ in different directions.
CONCLUSIONS: Using motion cues to enhance vessel contrast is a powerful tool for visualizing the capillary network, in the absence of contrast agents. The authors demonstrate a tool to study the microcirculation of healthy subjects noninvasively.
Authors:
Johnny Tam; Joy A Martin; Austin Roorda
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2009-11-11
Journal Detail:
Title:  Investigative ophthalmology & visual science     Volume:  51     ISSN:  1552-5783     ISO Abbreviation:  Invest. Ophthalmol. Vis. Sci.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-02-26     Completed Date:  2010-03-26     Revised Date:  2013-05-31    
Medline Journal Info:
Nlm Unique ID:  7703701     Medline TA:  Invest Ophthalmol Vis Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1691-8     Citation Subset:  IM    
Affiliation:
University of California, Berkeley and University of California, San Francisco, Joint Graduate Group in Bioengineering, Berkeley, California 94720-2020, USA. johnny@berkeley.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Algorithms
Capillaries / physiology
Fluorescein Angiography
Fovea Centralis / blood supply*
Humans
Image Processing, Computer-Assisted
Lasers / diagnostic use
Microcirculation / physiology
Ophthalmoscopes
Regional Blood Flow / physiology
Retinal Vessels / physiology*
Video Recording
Grant Support
ID/Acronym/Agency:
EY014375/EY/NEI NIH HHS
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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