Characterizing the collagen network structure and pressure-induced strains of the human lamina cribrosa

Yik Tung Tracy Ling, Ran Shi, Dan E. Midgett, Joan L. Jefferys, Harry A. Quigley, Thao D. Nguyen

Research output: Contribution to journalArticle

Abstract

PURPOSE. The purpose of this study was to measure the 2D collagen network structure of the human lamina cribrosa (LC), analyze for the correlations with age, region, and LC size, as well as the correlations with pressure-induced strains. METHODS. The posterior scleral cups of 10 enucleated human eyes with no known ocular disease were subjected to ex vivo inflation testing from 5 to 45 mm Hg. The optic nerve head was imaged by using second harmonic generation imaging (SHG) to identify the LC collagen structure at both pressures. Displacements and strains were calculated by using digital volume correlation of the SHG volumes. Nine structural features were measured by using a custom Matlab image analysis program, including the pore area fraction, node density, and beam connectivity, tortuosity, and anisotropy. RESULTS. All strain measures increased significantly with higher pore area fraction, and all but the radial-circumferential shear strain (Erh) decreased with higher node density. The maximum principal strain (Emax) and maximum shear strain (Cmax) also increased with larger beam aspect ratio and tortuosity, respectively, and decreased with higher connectivity. The peripheral regions had lower node density and connectivity, and higher pore area fraction, tortuosity, and strains (except for Erh) than the central regions. The peripheral nasal region had the lowest Emax, Cmax, radial strain, and pore area fraction. CONCLUSIONS. Features of LC beam network microstructure that are indicative of greater collagen density and connectivity are associated with lower pressure-induced LC strain, potentially contributing to resistance to glaucomatous damage.

Original languageEnglish (US)
Pages (from-to)2406-2422
Number of pages17
JournalInvestigative Ophthalmology and Visual Science
Volume60
Issue number7
DOIs
StatePublished - Jun 2019

Keywords

  • Beam network
  • Digital volume correlation
  • Inflation test
  • Optic nerve head
  • Pore area fraction

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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