Purpose: This thesis aimed to characterise and analyse the 3D micro- and nanoarchitecture of connective tissue within the lamina cribrosa (LC). Methods: The microarchitecture of load-bearing connective tissue components, elastin and fibrillar collagen, of the young, elderly and glaucomatous optic nerve head (ONH) was analysed following two-photon excited fluorescence, second harmonic generation and small angle light scattering. Microfocus and conventional small angle X-ray scattering were used to analyse ONH nanoarchitecture and the potential of X-ray microtomography (XMT) as a 3D imaging technique was evaluated. Results: Fibrillar collagen and elastic fibres stretched radially across the optic nerve (ON) canal in the LC, encircled the central retinal vessels and were absent in the prelamina. In the postlaminar ON septae, collagen was perpendicular to that in the LC. Differences in young and elderly ONH tissue included; wavy collagen bundles exclusively within the young ONH and distinct elastic fibres found in the elderly ONH. Analysis of ONH reconstructions of 3D SHG datasets revealed that elderly LCs contained higher fibrillar collagen content when compared to the young LCs. Interestingly, the connective tissue beams of the inferior-temporal LC quadrant were significantly more aligned in glaucoma when compared to age-matched controls. Distinct X-ray reflections, potentially elastin in the peripapillary sclera and representative of CNS myelin in the postlaminar ON were identified. XMT enabled quantification of the regional variation in LC thickness, connective tissue content, pore area and pore count, showing potential for 3D quantification without the need for tissue sectioning. Conclusion: Differences in the young and elderly ONH microarchitecture and nanoarchitecture include fibrillar collagen content, alignment and packing and the presence of elastic fibres. These data will be important for the development of finite element models that can predict ONHs at risk of developing glaucomatous optic neuropathy.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:600618 |
| Date | January 2014 |
| Creators | Jones, Hannah |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/59281/ |
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