This thesis explored some aspects of the relationship between structural progression of the glaucomatous optic nerve head (ONH) and functional progression of the visual field. Sixty-one individuals with a longitudinal series of ONH images were manually identified from a database of approximately 2800 individuals attending a hospital glaucoma clinic. The ONH images obtained from the various photographic sources were equalized, for each individual, in terms of ONH size. Custom-software was designed to enable the viewing of consecutive and chronologically different ONH image-pairs under monoscopic and stereoscopic conditions, with and without sequential flicker. The efficacy, for the identification of progressive glaucomatous loss, amongst the 61 individuals, of the four viewing techniques was qualitatively evaluated by two ophthalmologists. Stereo-flicker identified the largest number of cases of progression, although little agreement was present between the two ophthalmologists. The digital characteristics of the ONH images from 27 of the 61 individuals enabled quantitative digital stereo-planimetry. A weak positive curvilinear association was present, at baseline, between the reduction in the neuroretinal rim area and the outcomes of perimetry, including residual retinal ganglion cell (RGC) count. However, little agreement was again present between the two ophthalmologists. Little association was present with either ophthalmologist between progressive structural damage and functional damage. A separate manual search of 1000 individuals with glaucoma archived in ‘Open eyes’ identified 112 individuals with a minimum of 5 visual field examinations over a minimum of 5 years. The outcomes at each stimulus location of the differential light sensitivity, expressed in decibels (dB), and of the residual RGC count, against time to follow-up, were compared using univariate linear regression analysis. In general, residual RGC count identified progression, in terms of a greater statistical significance and/ or of more stimulus locations, at an earlier stage of the disease than sensitivity expressed in dB.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:667915 |
| Date | January 2015 |
| Creators | Malissova, Eleni |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/78319/ |
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