Optical coherence tomography: evaluation and clinical application

Muscat, Sarah (2003) Optical coherence tomography: evaluation and clinical application. PhD thesis, University of Glasgow.

Abstract

The ability to examine the appearance of the retina is of paramount importance for
the diagnosis and monitoring of ophthalmic disease and for the evaluation of
treatment outcomes. Direct cross-sectional imaging of retinal structure could be
useful for early diagnosis and more sensitive monitoring of a variety of retinal
conditions such as macular oedema and glaucoma. The view of the fundus given by
ophthalmoscopy provides very limited depth information and clinicians will often
have to resort to additional techniques such as flourescein angiography or visual field
testing for information on structural abnormalities within the retina. Other currently
available imaging techniques do not provide sufficient depth resolution to produce
useful cross-sectional images of retinal structure.
Optical coherence tomography (OCT) is a new imaging technique which is capable
of producing cross-sectional images of the retina with a resolution that surpasses that
of conventional imaging techniques. This new technique has axial resolution of
around 1 O.tm and can resolve individual retinal layers, thus providing information on
retinal structure. In principle, OCT is very similar to ultrasound however it makes
use of a light source rather than an acoustic one. The technique is non-contact and
non-invasive and is generally well tolerated by patients. This thesis describes the
evaluation of this new imaging technique with regards to its potential within routine
clinical practice.
A number of investigations were performed to fuffil this evaluation. Tests were
carried out to experimentally measure the system's resolution and the accuracy and
precision of measurements made from the OCT scans. A number of factors that
could affect the quality of the scans were identified and their effects were minimised
wherever possible. The software provided with the system was rigorously tested and
potential sources of error were identified. Various studies were undertaken to
quantify the repeatability and reproducibility of measurements made from scans and
normative values were established. These results were used to assess the ability of
the technique to detect and quantify several retinal disorders. The potential of the
technique for corneal imaging was investigated - a scanning protocol was
established and customised software for processing cornea! scans was developed.
The relationship between OCT bands and retinal morphology was investigated by
correlating scans from canine retina with corresponding light microscopy images and
by observing the position of retinal abnormalities on scans from patients with a
variety of conditions that affected different parts of the retina. Finally the clinical
potential of OCT was investigated by carrying out various studies on a number of
retinal conditions. Further clinical studies which combine anatomical information
from OCT with functional information from electrophysiology are currently
underway.
Current developments are aimed at improving the imaging processing features and
user interface so as to provide a more robust, user-friendly system for routine clinical
use.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QC Physics; R Medicine > RE Ophthalmology
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Supervisor's Name: Keating, Dr. David
• Date of Award: 2003
• Depositing User: Miss Fiona Riggans
• Unique ID: glathesis:2003-630
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 17 Mar 2009
• Last Modified: 10 Dec 2012 13:20
• URI: https://theses.gla.ac.uk/id/eprint/630