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Corneal structure and biomechanics: relationship to diagnosis and treatment of glaucoma and keratoconus

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thesis
posted on 28.03.2022, 22:29 authored by Deepa Viswanathan
This thesis extensively investigates the relationship of corneal structure and biomechanical profile to the diagnosis and treatment of two ocular disorders: glaucoma and keratoconus. The research papers arising out of these studies have been compiled to form this thesis by publication. The main hypotheses addressed by this PhD thesis include: 1. Baseline central corneal thickness could be a predictive factor of glaucoma progression 2. Ongoing change in corneal thickness may occur in glaucoma subjects and this might be related to glaucoma progression. 3. Altering the dynamic properties of the cornea by collagen crosslinking can affect the progression of disease in keratoconic subjects. Despite having different mechanisms, both conditions are significant causes of preventable blindness. Glaucoma is more prevelant in the older population whereas keratoconus tends to affect younger subjects. Interestingly, thinner corneas and altered biomechanics are related to glaucoma risk and also characteristic of keratoconus. The aim of the glaucoma studies was to identify longitudinal variation in corneal thickness and its relationship to antiglaucoma medications and visual field progression. This could provide some insight on the clinical relevance of repeat corneal thickness measurements in glaucoma practice. Our findings indicate that corneal thickness reduces slightly over time in eyes on topical prostaglandin therapy and that thinner corneas may be associated with an increased risk of visual field progression. The keratoconus studies aimed to explore the relationship between corneal structural and biomechanical characteristics, compare corneal imaging devices, analyse the sensitivity and specificity of biomechanical parameters in keratoconus detection and study the outcome of collagen crosslinking in adult and paediatric progressive keratoconic eyes. Knowledge from these studies would allow clinicians to identify and manage keratoconus more efficiently. Our results indicate significant correlations between corneal structural and biomechanical characteristics. We also demonstrated that some commercially available corneal imaging devices are not interchangeable in clinical practice and that newer biomechanical parameters are sensitive in detecting corneal ectasia. Furthermore, we validated the efficacy of the corneal collagen crosslinking procedure in adult and paediatric progressive keratoconic eyes.

History

Table of Contents

1. Introduction and review of the literature -- 2. Methods -- 3. Longitudinal effect of topical antiglaucoma medications on central corneal thickness -- 4. Relationship of change in central corneal thickness to visual field progression in eyes with glaucoma -- 5. Relationship of biomechanical profile to structural characteristics in normal, forme fruste keratoconic, keratoconic and crosslinked corneas -- 6. Comparative analysis of corneal measurements obtained from a scheimpflug camera and an integrated placido-optical coherence tomography device in normal and keratoconic eyes -- 7. Sensitivity and specificity of newer biomechanical waveform parameters in detecting keratoconus -- 8. Prospective longitudinal study of corneal collagen cross-linking in progressive keratoconus -- 9. Outcome of corneal collagen crosslinking for progressive keratoconus in paediatric patients -- 10A. Discussion and summary -- 10B. Conclusions and future directions -- References -- Appendix.

Notes

Includes bibliographical references Thesis by publication.

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Degree

PhD, Macquarie University, Faculty of Human Sciences, Australian School of Advanced Medicine

Department, Centre or School

Australian School of Advanced Medicine

Year of Award

2015

Principal Supervisor

Stuart L. Graham

Additional Supervisor 1

John J. Males

Additional Supervisor 2

Nikhil L. Kumar

Rights

Copyright Deepa Viswanathan 2015. Copyright disclaimer: http://www.copyright.mq.edu.au

Language

English

Extent

1 online resource (227 pages) illustrations

Former Identifiers

mq:44299 http://hdl.handle.net/1959.14/1068058