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Corneal structure and biomechanics: relationship to diagnosis and treatment of glaucoma and keratoconus
thesisposted on 2022-03-28, 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.
Table of Contents1. 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.
NotesIncludes bibliographical references Thesis by publication.
Awarding InstitutionMacquarie University
Degree TypeThesis PhD
DegreePhD, Macquarie University, Faculty of Human Sciences, Australian School of Advanced Medicine
Department, Centre or SchoolAustralian School of Advanced Medicine
Year of Award2015
Principal SupervisorStuart L. Graham
Additional Supervisor 1John J. Males
Additional Supervisor 2Nikhil L. Kumar
RightsCopyright Deepa Viswanathan 2015. Copyright disclaimer: http://www.copyright.mq.edu.au
Extent1 online resource (227 pages) illustrations
Former Identifiersmq:44299 http://hdl.handle.net/1959.14/1068058