April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
Effects of Lamina Cribrosa Microarchitecture on Biomechanics in Glaucoma
Author Affiliations & Notes
  • Ian C Campbell
    Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA
    Rehab R&D Center of Excellence, Atlanta VA Medical Center, Atlanta, GA
  • Baptiste Coudrillier
    Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA
  • Richard L Abel
    Surgery, Imperial College London, London, United Kingdom
  • C Ross Ethier
    Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA
    Rehab R&D Center of Excellence, Atlanta VA Medical Center, Atlanta, GA
  • Footnotes
    Commercial Relationships Ian Campbell, None; Baptiste Coudrillier, None; Richard Abel, None; C Ethier, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 4245. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Ian C Campbell, Baptiste Coudrillier, Richard L Abel, C Ross Ethier; Effects of Lamina Cribrosa Microarchitecture on Biomechanics in Glaucoma. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4245.

      Download citation file:


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

      ×
  • Supplements
Abstract
 
Purpose
 

To evaluate the effects of subject-specific lamina cribrosa (LC) beam microarchitecture (orientation and connective tissue volume fraction) on optic nerve head (ONH) biomechanics. Such effects are likely important in influencing retinal ganglion cell dysfunction in glaucoma.

 
Methods
 

In this preliminary study, a porcine ONH was scanned via contrast-enhanced micro-CT (μCT); however, the approach is general and is currently being extended to human ONHs. From the scan, the 3D spatial location and orientation of LC beams were both extracted using a Frangi filter image processing technique. This LC dataset was registered against an idealized model of the ONH and posterior sclera, specifically delineating the peripapillary sclera. Fiber-informed material properties were assigned to the various tissues of this region, and the effects of elevated intraocular pressure (IOP) were simulated using computer modeling (finite element) techniques. Results were compared with a reference case in which generic material properties for the LC were used.

 
Results
 

Compared to the reference case, inclusion of μCT-derived LC microarchitectural information reduced the computed average 1st principal strain (a measure of stretch) by 30.8% and maximum shear strain by 30.9%. Total displacement of the ONH was, on average, 4.0% lower in the fiber-informed model than in the generic model. Additionally, the strain field was more homogeneous in the fiber-informed LC than in the generic LC (Figure 1).

 
Conclusions
 

μCT provides a powerful tool to inject information about ONH connective tissue microarchitecture into biomechanical models of the LC. Isotropic, generic models of the LC over-estimate strain compared to anisotropic, subject-informed models, and the porous structure of the LC tends to homogenize strains within this region, reducing the presence of extreme values such that ONH axons experience minimal strain gradient.

 
 
Figure 1: A) Contrast-enhanced μCT cross section of porcine lamina cribrosa, from which local beam orientation and connective tissue volume fraction data were extracted. B) Computed mechanical strains in the LC were homogeneous and relatively low. Note that biomechanics of the posterior eye were computed; only results in LC are shown. C) Computed strains in the reference case, showing higher strains and less uniform magnitudes than in B.
 
Figure 1: A) Contrast-enhanced μCT cross section of porcine lamina cribrosa, from which local beam orientation and connective tissue volume fraction data were extracted. B) Computed mechanical strains in the LC were homogeneous and relatively low. Note that biomechanics of the posterior eye were computed; only results in LC are shown. C) Computed strains in the reference case, showing higher strains and less uniform magnitudes than in B.
 
Keywords: 473 computational modeling • 577 lamina cribrosa • 551 imaging/image analysis: non-clinical  
×
×

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.

×