Document Detail

Estimation of ocular rigidity in glaucoma using ocular pulse amplitude and pulsatile choroidal blood flow.
MedLine Citation:
PMID:  23349434     Owner:  NLM     Status:  MEDLINE    
PURPOSE: Theoretical models and animal studies have suggested that scleral rigidity plays an important role in the pathogenesis of glaucoma. The aim of this study was to present a noninvasive technique for estimating ocular rigidity (E) in vivo, and to compare the estimated rigidity between patients with open-angle glaucoma (OAG); ocular hypertension (OHT); suspect glaucomatous disc (GS); and normal subjects (N). We hypothesized that OHT patients would have higher rigidity.
METHODS: All patients underwent measurements of ocular pulse amplitude (OPA) using dynamic contour tonometry, pulsatile choroidal blood flow (ChBFP) using laser Doppler flowmetry; axial length (AL); and assessment of automated visual field mean deviation (MD). The ratio between OPA and ChBFP was calculated according to the Friedenwald's equation of ocular rigidity. The calculated ratio is denoted as (ER). The average ER values of the four diagnostic groups were compared using nonparametric tests. The relationship between ER and other ocular and systemic factors was examined using correlation and regression analysis.
RESULTS: A total of 257 subjects were included in the study (56 N, 108 OAG, 48 GS, and 45 OHT). ER correlated negatively with AL and positively with MD, signifying that a lower rigidity was associated with a longer eye and a worse (more negative) MD. ER was also found to be highest in OHT (0.235 ± 0.16) and lowest in OAG (0.188 ± 0.14; P = 0.01).
CONCLUSIONS: Estimated coefficient of ocular rigidity by OPA and ChBFP suggested that glaucoma patients had the lowest rigidity and OHT the highest. It supports the idea that a more compliant ocular shell may predispose the optic nerve head to intraocular pressure (IOP)-related damage.
Jing Wang; Ellen E Freeman; Denise Descovich; Paul J Harasymowycz; Alvine Kamdeu Fansi; Gisele Li; Mark R Lesk
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2013-03-07
Journal Detail:
Title:  Investigative ophthalmology & visual science     Volume:  54     ISSN:  1552-5783     ISO Abbreviation:  Invest. Ophthalmol. Vis. Sci.     Publication Date:  2013 Mar 
Date Detail:
Created Date:  2013-03-08     Completed Date:  2013-04-29     Revised Date:  2013-08-08    
Medline Journal Info:
Nlm Unique ID:  7703701     Medline TA:  Invest Ophthalmol Vis Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1706-11     Citation Subset:  IM    
Maisonneuve-Rosemont Hospital Research Centre, Montreal, Quebec, Canada.
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MeSH Terms
Case-Control Studies
Choroid / blood supply
Glaucoma, Open-Angle / physiopathology*
Laser-Doppler Flowmetry
Middle Aged
Ocular Hypertension / physiopathology*
Pulsatile Flow
Regional Blood Flow
Sclera / pathology*
Tonometry, Ocular

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

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