An in vivo investigation of optic nerve head microstructure in primary open angle glaucoma

Bartlett, Ryan Lee 2020. An in vivo investigation of optic nerve head microstructure in primary open angle glaucoma. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Glaucoma remains the leading cause of irreversible blindness in the world. Since retinal ganglion cell (RGC) axonal degeneration precedes permanent vision loss, identification of ONH parameters affected in the earliest stages of primary open angle glaucoma (POAG) is critical to ensure early diagnosis. This cross-sectional study used enhanced-depth imaging optical coherence tomography (EDI-OCT; 1040/70nm) to acquire 10° and 20° scans centred on the ONH (glaucomatous; n=128 or healthy controls; n=60). Regional measures of prelamina and LC depth and thickness, nerve fibre layer thickness at ONH border (bNFL) and peripapillary (pNFL), neuroretinal minimum rim width; (MRW) and area; (MRA) were analysed. This is the first study to quantify volumetric parameters including optic cup, prelamina and LC volume, and also Bruch’s membrane opening (BMO) surface area. Furthermore, LC connective tissue alignment was probed regionally and depth-wise within the LC. Statistical modelling was performed to identify ONH parameters that best contributed to characterisation of ONHs in the earliest stages of POAG. Regional measures of prelamina depth and thickness, and LC thickness were able to differentiate between control eyes and preperimetric (PG), and early glaucoma (EG) (P<0.05). Additionally, EG LC volume was significantly less than in controls (P<0.05). Significant associations of these parameters with loss of VF sensitivity (VF Mean deviation [MD]) were identified. Border and pNFL thickness, MRW (but not MRA) significantly differed between controls and PG and EG (P<0.05); and decreased with VF MD. Lamina cribrosa connective tissue alignment altered in a region and depth specific manner between PG LC and controls, or EG LCs (P<0.05), providing an original in vivo indicator of disease. In conclusion, in vivo ONH and NFL parameters are able to discriminate between healthy ONHs and early POAG ONHs; providing a group index with potential as a novel biomarker for early diagnosis, critical to personalised clinical decision making.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Optometry and Vision Sciences
Subjects:	R Medicine > RE Ophthalmology
Uncontrolled Keywords:	Glaucoma, Optic nerve head, Optical coherence tomography
Date of First Compliant Deposit:	5 March 2021
Last Modified:	04 Mar 2022 02:30
URI:	https://orca.cardiff.ac.uk/id/eprint/139298

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