How Does Segmental Outflow Affect Outflow Resistance?

Principal Investigator

Tulane University
New Orleans, LA
Acknowledgement
Recipient of the Thomas R. Lee award for National Glaucoma Research

Project Goals

Dr. Overby proposes to study how the hydrodynamic patterns of aqueous humor outflow change in response to stimuli that affect outflow resistance. His hypothesis is because aqueous humor is confined to flow through only a fraction of total area of outflow pathway, outflow resistance is correlated to the area that is actively involved in hydrodynamic filtration of aqueous humor.

Project Summary

Glaucoma is a disease typically associated with elevated intraocular pressure (IOP) caused by increased resistance to aqueous humor outflow. Glaucoma is treated clinically by reducing IOP, but the precise factors responsible for controlling IOP and outflow resistance are not well understood. To improve the understanding of outflow resistance, Dr. Overby proposes to study how the hydrodynamic patterns of aqueous humor outflow change in response to stimuli that affect outflow resistance. His hypothesis is because aqueous humor is confined to flow through only a fraction of total area of outflow pathway, outflow resistance is correlated to the area that is actively involved in hydrodynamic filtration of aqueous humor. To test this hypothesis, he will aim to develop a new tracer method that will combine with confocal microscopy to visualize the hydrodynamic patterns of outflow and measure the active area of aqueous humor filtration in human eyes. The second aim is to use this tracer technique to quantify the relationship between outflow resistance and filtration area for changing IOP that causes a change in outflow resistance. The long-term goal of this project is to translate this fundamental understanding of outflow hydrodynamics into a strategy to reduce outflow resistance and IOP in glaucomatous eyes.

Publications

Overby, D.R., Stamer, W.D. and Johnson, M. (2009) The changing paradigm of outflow resistance generation: Towards synergistic models of the JCT and inner wall endothelium. Exp. Eye Res. 88, 656-670.  

Battista, S.A., Lu, Z., Hofmann, S., Freddo, T., Overby, D.R., and Gong, H. (2008) Acute IOP elevation reduces the area available for aqueous humor outflow and induces meshwork herniations in collector channels of bovine eyes. Invest. Ophthalmol. Vis. Sci. 49, 5346-5352.  

Lu, Z., Overby, D.R., Scott, P.A., Freddo, T.F., and Gong, H. (2008) The mechanism of increasing outflow facility by rho-kinase inhibition with Y-27632 in bovine eyes. Exp. Eye Res. 86, 271-281.  

Scott, P.A., Overby, D.R., Freddo, T.F., and Gong, H. (2007) Comparative studies between species that do and do not exhibit the washout effect. Exp. Eye Res. 84, 435-443.  
 

First published on: June 11, 2008

Last modified on: February 27, 2024