Detection and understanding the role of Ultraviolet Radiation in Keratoconus

Abstract

Introduction

Keratoconus is an eye disorder characterised by progressive corneal thinning and steepening of the cornea leading to impairment in vision and decreased quality of life. The detection of disease at its early stages remains challenging. This body of work aims to improve our understanding of various corneal imaging parameters for detecting early keratoconus and to provide a framework for investigating the role of ultraviolet radiation in the pathogenesis of keratoconus.

Methods

A retrospective review of patients at the Sydney Eye Hospital, Sydney, Australia with early keratoconus with age-matched controls was conducted utilising the Save Sight Keratoconus Registry. Data from a variety of corneal parameters were extracted from Pentacam tomography and analysed to determine their diagnostic utility. This study also devised a method to investigate mitochondrial DNA as a marker for ultraviolet radiation damage in the cornea, proposing a protocol for investigating the link between ultraviolet radiation exposure and keratoconus.

Results

In distinguishing normal corneas from early keratoconic ectasia, Belin Ambrósio enhanced ectasia display total deviation value demonstrated the highest discriminative power followed by Keratoconus index, Index of vertical asymmetry, Deviation of normality of relational thickness and the Belin ABC Score. All parameters proved to have excellent positive predictive value, making them useful in diagnosing early keratoconus. This thesis also outlined a framework and protocol for investigating the causative role of ultraviolet radiation exposure in keratoconus using mitochondrial DNA analysis of the cornea and sun exposed and non-sun exposed skin.

Conclusion

The Belin Ambrósio enhanced ectasia display had the highest discriminative power in distinguishing early keratoconus from a normal cornea in our patient cohort. A clinical study could enable the role of ultraviolet radiation in keratoconus to be elucidated.