NDLI: A framework for comparing structural and functional measures of glaucomatous damage

Please wait, while we are loading the content...

Year: 2016, Volume: 52

Year: 2015, Volume: 49

Year: 2015, Volume: 46

Year: 2015, Volume: 0

Year: 2014, Volume: 42

Year: 2014, Volume: 41

Year: 2014, Volume: 0

Year: 2013, Volume: 37

Year: 2013, Volume: 36

Year: 2013, Volume: 35

Year: 2013, Volume: 34

Year: 2013, Volume: 33

Year: 2013, Volume: 32C

Year: 2013, Volume: 32

Year: 2013, Volume: 0

Year: 2012, Volume: 31

Year: 2011, Volume: 30

Year: 2010, Volume: 29

Year: 2009, Volume: 28

Year: 2008, Volume: 27

Year: 2007, Volume: 26

Year: 2007, Volume: 26, Issue: 6

Genetic and epigenetic mechanisms of gene regulation during lens development

Iron homeostasis and toxicity in retinal degeneration

A framework for comparing structural and functional measures of glaucomatous damage

Year: 2007, Volume: 26, Issue: 5

Year: 2007, Volume: 26, Issue: 2

Year: 2007, Volume: 26, Issue: 1

Year: 2006, Volume: 25

Year: 2005, Volume: 24

Year: 2004, Volume: 23

A framework for comparing structural and functional measures of glaucomatous damage

Content Provider	PubMed Central
Author	Hood, Donald C. Kardon, Randy H.
Abstract	While it is often said that structural damage due to glaucoma precedes functional damage, it is not always clear what this statement means. This review has two purposes: first, to show that a simple linear relationship describes the data relating a particular functional test (standard automated perimetry (SAP)) to a particular structural test (optical coherence tomography (OCT)); and, second, to propose a general framework for relating structural and functional damage, and for evaluating if one precedes the other. The specific functional and structural tests employed are described in Section 2. To compare SAP sensitivity loss to loss of the retinal nerve fiber layer (RNFL) requires a map that relates local field regions to local regions of the optic disc as described in Section 3. When RNFL thickness in the superior and inferior arcuate sectors of the disc are plotted against SAP sensitivity loss (dB units) in the corresponding arcuate regions of the visual field, RNFL thickness becomes asymptotic for sensitivity losses greater than about 10 dB. These data are well described by a simple linear model presented in Section 4. The model assumes that the RNFL thickness measured with OCT has two components. One component is the axons of the retinal ganglion cells and the other, the residual, is everything else (e.g. glial cells, blood vessels). The axon portion is assumed to decrease in a linear fashion with losses in SAP sensitivity (in linear units); the residual portion is assumed to remain constant. Based upon severe SAP losses in anterior ischemic optic neuropathy (AION), the residual RNFL thickness in the arcuate regions is, on average, about one-third of the premorbid (normal) thickness of that region. The model also predicts that, to a first approximation, SAP sensitivity in control subjects does not depend upon RNFL thickness. The data (Section 6) are, in general, consistent with this prediction showing a very weak correlation between RNFL thickness and SAP sensitivity. In Section 7, the model is used to estimate the proportion of patients showing statistical abnormalities (worse than the 5th percentile) on the OCT RNFL test before they show abnormalities on the 24-2 SAP field test. Ignoring measurement error, the patients with a relatively thick RNFL, when healthy, will be more likely to show significant SAP sensitivity loss before statistically significant OCT RNFL loss, while the reverse will be true for those who start with an average or a relatively thin RNFL when healthy. Thus, it is important to understand the implications of the wide variation in RNFL thickness among control subjects. Section 8 describes two of the factors contributing to this variation, variations in the position of blood vessels and variations in the mapping of field regions to disc sectors. Finally, in Sections 7 and 9, the findings are related to the general debate in the literature about the relationship between structural and functional glaucomatous damage and a framework is proposed for understanding what is meant by the question, ‘Does structural damage precede functional damage in glaucoma?’ An emphasis is placed upon the need to distinguish between “statistical” and “relational” meanings of this question.
Related Links	http://dx.doi.org/10.1016/j.preteyeres.2007.08.001
Starting Page	688
File Format	PDF
ISSN	13509462
Journal	Progress in retinal and eye research
Issue Number	6
Volume Number	26
Language	English
Publisher Date	2007-11-01
Access Restriction	Open
Subject Keyword	eye research Research in Higher Education
Content Type	Text
Resource Type	Article
Subject	Ophthalmology Sensory Systems

Central Library (ISO-9001:2015 Certified)
Indian Institute of Technology Kharagpur
Kharagpur, West Bengal, India | PIN - 721302

See location in the Map
03222 282435
Mail: support@ndl.gov.in

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in