Three-dimensional optical coherence tomography imaging of the optic nerve head.
Doctoral thesis, UCL (University College London).
Background: the primary site of injury in glaucoma is likely to be at the lamina cribrosa (LC), deep within the optic nerve head (ONH). Optical coherence tomography (OCT) in glaucoma has, to date, focused on the detection of nerve fibre loss. Spectral domain OCT (SDOCT) has improved speed and axial resolution, allowing acquisition of three-dimensional ONH volumes and may capture targets deep within the ONH. This thesis explores the capabilities and potential of deep SDOCT imaging in the monkey ONH. Plan of research: an investigation was conducted into the detection of key landmarks that would be necessary for future quantification strategies. In particular, detection of the neural canal opening (NCO) was assessed and how the NCO relates to what is clinically identified as the disc margin. The next phase involved clarifying the anatomical and histological basis of ONH structures observed within SDCOT volumes, by comparison with histological sections and disc photographs. Finally, quantification strategies for novel parameters based on deep targets were developed and used to detect chronic longitudinal changes in experimental glaucoma and acute changes following IOP manipulation. Results: SDOCT reliably detects the NCO, which can be used as an anchoring structure for reference planes. Usually the NCO equates to the disc margin but disc margin architecture can be complex and highly variable. SDOCT captures the prelaminar tissue and anterior LC surface. Prelaminar thinning and posterior LC displacement were both detected longitudinally in experimental glaucoma. Prelaminar thinning was observed with acute IOP elevation; posterior LC movement was rare. Significance: deep ONH structures, including the LC, are realistic targets for clinical imaging. These imaging targets may be useful in the detection of glaucoma progression and in the verification of ex-vivo models of ONH biomechanical behaviour.
|Title:||Three-dimensional optical coherence tomography imaging of the optic nerve head|
|Open access status:||An open access version is available from UCL Discovery|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Ophthalmology|
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