English Studies / M.A.(English))

No description available.

No description available.

No description available.

Common ancestry prevents scientists from using traditional statistical tests in dimensional comparisons that span entire clades. Data in these cases are non-independent, so a variety of special statistical methods have been developed specifically for phylogenetic comparative analyses. A phylogenetic least squares method was used to re-examine four published datasets detailing structural correlates of eyes while factoring in the different ways the phylogeny was expected to affect the covariance in trait values. All analyses were carried out in a strict phylogenetic context, using published time-calibrated phylogenies and the statistical platform R. Specifically, Pagel’s lambda was used to determine how much of an influence phylogeny had on each pair of traits. In all tested soft and hard tissue correlations, the phylogeny of the species slightly altered the trend lines of the measurements, compared to lines that did not take phylogenetic relationship into consideration. These results do not contradict previous results, but further work needs to be done to determine the implications that significant phylogenetic signal has on subsequent analyses. Future studies should account for phylogenetic relationships which have been shown to influence the relationship between traits.

The unique properties of the confocal Scanning Laser Ophthalmoscope [cSLO] have been exploited in tandem with computer-aided image analysis to detect and quantify macular lesions. Healthy volunteers and patients with macular ischaemia, oedema and hole formation underwent fluorescein angiography, tomography and indirect mode imaging using the cSLO. For macular ischaemia, a computer program has been developed to identify poorly perfused areas based on fluorescence and temporal data extracted systematically from fluorescein angiograms. These parametric images, <I>viz</I>., <I>maximum fluorescence, time-to-maximum </I>and <I>ischaemia</I>, combine physiological with anatomical data. The ischaemia program has been validated using a human Gold Standard on a panel of five angiograms using Receiver Operator Characteristic analysis. The program performs favourably against a panel of ophthalmologists for angiograms of diabetic retinopathy. Computer algorithms have been developed for extracting topographical features from tomographic images of macular lesions causing thickening or thinning, such as oedema and holes. The information has been presented as <I>topography </I>and <I>thickness</I> parametric images. The novel <I>thickness</I> images show three-dimensional data in an easily assimilable form. The indirect mode technique readily reveals retinal and subretinal lesions, including macular oedema, macular hole, choroidal naevi and retinal pigment epithelial detachment without the need for any specialised viewing equipment or image processing. We have made significant progress towards developing a research and potential clinical tool for the detection and accurate quantification of macular pathology to facilitate the better understanding, diagnosis and clinical management of these blinding conditions.

English Studies / M.A.(English))

No description available.

No description available.

No description available.