Linked Life Data

9114506

Source:http://linkedlifedata.com/resource/pubmed/id/9114506

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1997-5-15
pubmed:abstractText
Optic disk reflectance was measured from 27 normal observers with their physiological lenses (aged 21-74 yr) and from two pseudophakic observers (aged 69 and 70 yr) with use of a Utrecht fundus reflection densitometer. Psychophysical heterochromatic flicker photometric luminance matches (10 degrees field) were obtained on the same group of the observers. A four-parameter model incorporating lens density, hemoglobin absorption, optic disk reflectance, and superficial stray light was used to fit the reflectometric data. A model incorporating lens density and the Judd revised spectral luminous-efficiency function was used to fit the psychophysical data. The lens-density spectrum used the two-factor aging model of Pokorny, et al. [Appl. Opt. 26, 1437 (1987)]. The lens density for each normal observer was estimated through a least-squares fitting procedure yielding an estimated lens age. For the reflectometric data the observer's chronological age agreed with estimated lens age with a correlation coefficient of 0.92. The reflectometric regression line underestimated chronological age by approximately 5 yr. The mean reflectance of the optic disk was 0.047 with standard error of the mean of 0.0044. Data from the pseudophakic observers were well described when corneal density was used to replace lens density. The lens density was also estimated from the psychophysical data. The observer's chronological age agreed with psychophysically estimated lens age with a correlation coefficient of 0.92. It was concluded that the in vivo lens density can be estimated from the reflectance spectrum measured off the optic disk. The reflectance spectrum of the optic disk was inferred to be close to spectrally neutral.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1084-7529
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
953-60
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Optical density of the human lens.
pubmed:affiliation
University of Chicago, Illinois 60637, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.