June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
Intraocular Pressure (IOP) Elevation Reduces Schlemm’s Canal Cross-Sectional Area (SC-CSA) in Living Human Eyes
Author Affiliations & Notes
  • Larry Kagemann
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA
  • Bo Wang
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA
  • Gadi Wollstein
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
  • Hiroshi Ishikawa
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA
  • Zach Nadler
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
  • Jessica Nevins
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
  • Ian Sigal
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA
  • Jonathan Grimm
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
  • Richard Bilonick
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
    Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA
  • Joel Schuman
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA
  • Footnotes
    Commercial Relationships Larry Kagemann, None; Bo Wang, None; Gadi Wollstein, Allergan (C); Hiroshi Ishikawa, None; Zach Nadler, None; Jessica Nevins, None; Ian Sigal, None; Jonathan Grimm, None; Richard Bilonick, None; Joel Schuman, Carl Zeiss Meditec, Inc. (P)
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 1440. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Larry Kagemann, Bo Wang, Gadi Wollstein, Hiroshi Ishikawa, Zach Nadler, Jessica Nevins, Ian Sigal, Jonathan Grimm, Richard Bilonick, Joel Schuman; Intraocular Pressure (IOP) Elevation Reduces Schlemm’s Canal Cross-Sectional Area (SC-CSA) in Living Human Eyes. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1440.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract
 
Purpose
 

Previously, we demonstrated reduced SC-CSA with increased perfusion pressure in a cadaveric flow model. The purpose of the present study was to determine the effect of acute IOP elevation on SC-CSA in living human eyes.

 
Methods
 

The temporal limbus of 27 eyes of 14 healthy subjects (10 male, 4 female, age 36 ± 13) was imaged by spectral-domain optical coherence tomography (Cirrus HD-OCT, Carl Zeiss Meditec, USA) at baseline and with IOP elevation (ophthalmodynamometer set at 30 Grms force). IOP was measured at baseline and with IOP elevation by Goldmann applanation tonometry. Vascular landmarks were used to identify corresponding locations in baseline and IOP elevation scan volumes. SC-CSA at 5 locations within a 1 mm length of SC was measured in ImageJ as described previously (IOVS 2010; 51(8): 4054-4059). The effect of IOP elevation on SC-CSA was quantified by linear mixed-effects model.

 
Results
 

Mean IOP increase was 189% (Table). Mean SC-CSA was decreased 32% (p < 0.001; Figure, Table). The estimate (95% confidence interval) for SC-CSA response to IOP change was -66.6 (-80.6 to -52.7) μm2/mmHg.

 
Conclusions
 

Acute IOP elevation significantly reduces SC-CSA in healthy eyes. Acute dynamic response to IOP elevation may be a useful future characterization of ocular health in the management of glaucoma.

 
 
IOP and Schlemm’s canal cross-sectional area (SC-CSA) at baseline and elevated pressure. Mean (Standard deviation) are presented.
 
IOP and Schlemm’s canal cross-sectional area (SC-CSA) at baseline and elevated pressure. Mean (Standard deviation) are presented.
 
 
Numerous vascular landmarks (yellow arrows) were used to identify the same location for measurement at 2 pressures (top). Schlemm’s canal was visibly compressed at high IOP (bottom).
 
Numerous vascular landmarks (yellow arrows) were used to identify the same location for measurement at 2 pressures (top). Schlemm’s canal was visibly compressed at high IOP (bottom).
 
Keywords: 550 imaging/image analysis: clinical • 568 intraocular pressure  
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×