| Comparative In Vitro Flow Study of 3 Different Ex-PRESS Miniature Glaucoma Device Models. | |
| | |
MedLine Citation:
|
PMID: 22274666 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
|
PURPOSE:: To determine the flow characteristics of the 3 different models of the Ex-PRESS miniature glaucoma device in a controlled laboratory study. MATERIALS AND METHODS:: The 3 different Ex-PRESS models (P-50, R-50, and P-200; Optonol Ltd; now Alcon Lab) were tested using a gravity-driven flow test. Three samples of each of the 3 Ex-PRESS models were subjected to a constant gravitational force of fluid at 5 different pressure levels (5 to 25 mm Hg). Four measurements per sample were taken at each pressure level. The main outcome measure was flow rate (Q) (µL/min). Resistance (R) was calculated by dividing pressure (P) by the measured flow (Q). RESULTS:: The flow rate was primarily pressure dependent. The P-200 model (internal diameter 200 µm) showed a statistically significant higher flow rate and lower resistance compared with both the P-50 and R-50 models (internal diameter 50 µm) (P<0.0001). The P-50 and R-50 models demonstrated similar flow rates (P=0.08) despite their difference in tube length (2.64 vs. 2.94 mm). CONCLUSIONS:: The 3 models of the Ex-PRESS mini shunt behaved in vitro as simple flow resistors by creating a relatively constant resistance to flow. Tube diameter was the only parameter with significant impact on flow and resistance. All models demonstrated flow rates per unit of pressure much higher than the outflow facility of a healthy human eye. |
| | |
Authors:
|
Stephan Estermann; Kanokwan Yuttitham; Julie A Chen; On-Tat Lee; Robert L Stamper |
Related Documents
:
|
15797266 - Relationship of inspiratory flow rate and volume on digit tip skin and ulnar artery vas... 140716 - A trial of the comparability of peak expiratory flow meters in schoolchildren. 15764066 - Effects of cold dry air nasal stimulation on airway mucosal blood flow in humans. 9387966 - Dependence of forced vital capacity manoeuvre on time course of preceding inspiration i... 18533926 - What is your diagnosis? pleural fluid from a neonatal thoroughbred filly with pneumonia. 9470056 - Acetylcholine-induced vasodilatation in the human peripheral circulation is independent... |
Publication Detail:
|
Type: JOURNAL ARTICLE Date: 2012-1-20 |
Journal Detail:
|
Title: Journal of glaucoma Volume: - ISSN: 1536-481X ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
|
Created Date: 2012-1-25 Completed Date: - Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 9300903 Medline TA: J Glaucoma Country: - |
Other Details:
|
Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
|
*Department of Ophthalmology, University of California San Francisco (UCSF), San Francisco, CA †Augenklinik Stadtspital Triemli, Zurich, Switzerland. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Klinefelter Syndrome Associated With Goniodysgenesis.
Next Document: Dampening of Diurnal Intraocular Pressure Fluctuation by Combined Trabeculotomy and Sinusotomy in Ey...