City Research Online

Abstract

A prospective longitudinal trial, involving 108 eyes with transplanted corneas was carried out. The object was to use sequential observations taken from the same eye to investigate changes over time. The two variables studied were corneal topography and corneal touch sensitivity. Keratographs were obtained using the Photo Electronic Keratograph (PEK). An analysis technique was developed which enabled clinically meaningful topographical components to be derived from measurements of the keratograph. These components were; spherical equivalent, asymmetry, axis of asymmetry, regular astigmatism and its axis, and an irregularity component. The changes in astigmatism and irregularity were analysed using Multilevel Modelling. The principal results were that MK storage medium produced higher starting values for astigmatism, and that equal donor and host diameters gave a more rapid reduction of astigmatism in the period up to suture removal. No single factor determined astigmatism after suture removal.

The starting value for irregularity was significantly higher in repeat transplants, but no single factor appeared to determine the rate of reduction of irregularity. Corneal touch sensitivity was measured with a Cochet Bonnet aesthesiometer, and revealed a slow but progressive resensitisation. There was a very large inter-subject variation. The central sensitivity was zero in more than 60% of the eyes at the five year stage. By ten years this proportion had reduced to just over 20%.

Publication Type:	Thesis (Doctoral)
Subjects:	R Medicine > RZ Other systems of medicine
Departments:	School of Health & Psychological Sciences > Optometry & Visual Sciences School of Health & Psychological Sciences > School of Health & Psychological Sciences Doctoral Theses Doctoral Theses

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