Refractive error, particularly myopia, is a significant visual problem considered to result from a complex interplay between genetics and environmental influences. While there has been a worldwide increase in the prevalence of myopia in recent years, the aetiology of myopia is not yet known. Emmetropisation is the process of normal eye growth during development such that refractive error stabilises at, or close to, emmetropia. This has been shown to be an active process influenced by the visual environment. Previous animal studies have shown that emmetropisation can be disrupted by introducing abnormal optical factors into the central and/or peripheral visual field. Differences in the optical and biometric properties of the emmetropic, myopic, and hyperopic eye have previously been found. The aim of this thesis was to extend previous work by investigating several important biometric and optical characteristics, in emmetropic, myopic and hyperopic eyes, in order to establish any systematic refractive group differences, which may explain the failure of the emmetropisation process. The results presented in this thesis show clear differences between the shape and refractive characteristics of the peripheral retina between myopic, emmetropic and hyperopic subjects. These results suggest that refractive error group dependent differences in the peripheral retina could be a key correlate of refractive error development. Optical properties of the eye, specifically pupil diameter, monochromatic higher order aberrations, and chromatic aberration were shown not to vary significantly between refractive groups, suggesting that these factors are unlikely to play any major role in the development of myopia. It could be, however, that the optical properties of the eye are a consequence of myopia development. Alternatively, the optical properties of the eye vary before myopia develops, or reaches adult levels.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:601635 |
| Date | January 2013 |
| Creators | Orr, Janis B. |
| Publisher | Glasgow Caledonian University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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