May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
The Effect of Lamina Cribrosa Thickness and Position on Optic Nerve Head Biomechanics
Author Affiliations & Notes
  • I. A. Sigal
    Devers Eye Institute, Portland, Oregon
    Ocular Biomechanics,
    Tulane University, New Orleans, Louisiana
  • H. Yang
    Devers Eye Institute, Portland, Oregon
    Tulane University, New Orleans, Louisiana
  • M. D. Roberts
    Devers Eye Institute, Portland, Oregon
  • J. L. Grimm
    Devers Eye Institute, Portland, Oregon
  • C. F. Burgoyne
    Devers Eye Institute, Portland, Oregon
  • J. C. Downs
    Devers Eye Institute, Portland, Oregon
  • Footnotes
    Commercial Relationships  I.A. Sigal, None; H. Yang, None; M.D. Roberts, None; J.L. Grimm, None; C.F. Burgoyne, None; J.C. Downs, None.
  • Footnotes
    Support  NIH-BRIN/INBRE Grant P20 RR16456
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 3668. doi:https://doi.org/
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      I. A. Sigal, H. Yang, M. D. Roberts, J. L. Grimm, C. F. Burgoyne, J. C. Downs; The Effect of Lamina Cribrosa Thickness and Position on Optic Nerve Head Biomechanics. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3668. doi: https://doi.org/.

      Download citation file:


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

      ×
  • Supplements
Abstract
 
Purpose:
 

It has been suggested that susceptibility to glaucoma depends on the specific mechanical response of an individual’s lamina cribrosa (LC) to increases in IOP, but the nature of this dependence is still not clear. Our objective was to estimate the effects of two aspects of LC geometry, thickness and position (relative to the anterior laminar insertion), on its mechanical response.

 
Methods:
 

A specimen-specific 3D finite element model of the LC of a normal monkey eye was reconstructed from high resolution histology images using techniques previously described [IOVS, 2004, 45(12) and IOVS, 2007, 48(5)]. The geometry of the LC was then modified using newly developed morphing techniques to produce a series of models with varying degrees of LC thickness and position. LC position ranged from flat to deep and thickness from one third to three times baseline. The mechanical response of each model to an increase in IOP from 10 to 45 mmHg was simulated and characterized by tensile strain and von Mises stress.

 
Results:
 

LC thickness and position affected LC mechanical response, such that on the geometries studied median magnitudes of tensile strain ranged from 2 to 6%, and of von Mises stress from 5 to 22 x IOP. Everything else being equal, either a thinner or a flatter LC led to increased levels of strain and stress. Moreover the dependence of stress and strain on thickness and position were non-linear, and non-additive. For example, thinning the LC to 1/3 baseline thickness increased the median von Mises stress by 25% in a flat LC and 64% in a deep LC (34% and 64%, respectively for tensile strain). These results extend to specimen-specific geometries previous findings obtained with generic models.

 
Conclusions:
 

Both thinning and flattening of the LC individually and together led to increased levels of IOP-induced stress and strain within the LC for a given IOP. These data represent the first application of novel morphing techniques to 3D reconstructions of the laminar cribrosa, and suggest how laminar thickness and position may influence the biomechanical environment of the optic nerve head at all levels of IOP.  

 
Keywords: lamina cribrosa • computational modeling • 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.

×