CORNEAL NERVES, SENSITIVITY AND TEAR NEUROPEPTIDES IN KERATOCONUS

Download files
Access & Terms of Use
open access
Copyright: Mandathara Sudharman, Preeji
Altmetric
Abstract
This thesis aimed to evaluate changes in corneal nerves, sensitivity, tear proteins and neuropeptides and their associations with other variables such as ocular symptoms, tear osmolarity, tear volume and ocular surface health in keratoconus. Corneal sensitivity was measured with 0.08mm nylon filament of a Cochet-Bonnet aesthesiometer, corneal nerves were mapped using laser in vivo confocal microscopy and concentrations of total protein, substance P (SP), calcitonin gene related peptide (CGRP) and lactoferrin in basal tears were quantified using enzyme immuno-assays in a cross-sectional study of keratoconus subjects. This study demonstrated that corneal sensitivity and sub-basal nerve fibre density were reduced, tortuosity of nerve fibres was increased and concentrations of total tear protein and lactoferrin were reduced in keratoconus. There was an inverse relation between tear lactoferrin and neuropeptides SP and CGRP. Increased corneal sensitivity (reduced threshold) was associated with increased ocular symptoms whereas reduced corneal sensitivity was associated with increased corneal staining. Contact lens wear affected corneal sensitivity, corneal nerves and concentration of total tear protein. Epithelial dendritic cells were common in the central cornea and their density and morphology were associated with nerve tortuosity. Reduced corneal sensitivity, increased tortuosity of corneal nerves, corneal scarring and reduced concentration of tear lactoferrin were associated with better tolerance to contact lens wear. This study suggests that changes in corneal nerves and sensitivity could be responsible for changes at the ocular surface and in tear protein concentrations, which may affect the success of management options for keratoconus such as contact lens wear. The presence of mature epithelial dendritic cells in the central cornea and reduction in the anti-inflammatory tear protein lactoferrin, and a negative association between concentrations of tear lactoferrin and neuropeptides, may provide evidence for inflammation in keratoconus. Overall, these results indicate that keratoconus may show characteristics consistent with neuro-degenerative diseases where inflammation plays a significant role. While corneal collagen cross linking (CXL) may halt the progression of keratoconus, the procedure may not reverse the corneal nerve damage and biochemical changes in the tears in keratoconus subjects. The persistence of significant number of epithelial dendritic cells following CXL, suggest a chronic inflammation which may adversely impact the success of future management options such as corneal transplantation.
Persistent link to this record
Link to Publisher Version
Link to Open Access Version
Additional Link
Author(s)
Mandathara Sudharman, Preeji
Supervisor(s)
Willcox, Mark
Stapleton, Fiona
Creator(s)
Editor(s)
Translator(s)
Curator(s)
Designer(s)
Arranger(s)
Composer(s)
Recordist(s)
Conference Proceedings Editor(s)
Other Contributor(s)
Corporate/Industry Contributor(s)
Publication Year
2017
Resource Type
Thesis
Degree Type
PhD Doctorate
UNSW Faculty
Files
download public version.pdf 2.31 MB Adobe Portable Document Format
Related dataset(s)