Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 40 for “"RE Ophthalmology"”.
-
New objective and psychophysical techniques to study the processing of visual signals with emphasis on chromatic afterimages
The research work described in this thesis embodies a number of studies designed to investigate human vision with emphasis on aspects of the pupil response and chromatic mechanisms in relation to the perceived chromatic afterimages. The aim of the first study was to establish the relationship …
-
Chromatic sensitivity: effects of light level and selective photoreceptor adaptation
When the light reflected from an object differs in spectral composition to the surrounding background these spectral differences are reflected in the excitation levels produced in each class of photoreceptor. The ability to see colours and to notice small colour differences is strongly affected by …
-
The effect of aberrations and light scatter on visual performance at photopic and mesopic light levels
… developed to assess the minimum spatial vision requirements for commercial pilots. The goal of the CAA test was for it to be sensitive to retinal image degradation in subjects who had undergone excimer laser refractive surgery. Increased aberrations and scattered light or abnormal processing of …
-
A study of case finding for chronic open angle glaucoma by UK community optometrists
In 2009 approximately 480,000 people were affected by COAG in England. Furthermore, glaucoma sufferers and suspects are responsible for over one million glaucoma-related outpatient visits annually. Community optometrists make over 95% of suspect COAG referrals, identifying suspects through …
-
Eye movements, search and perception of visual field defects in glaucoma
Glaucoma is a progressive disease of the optic nerve that can result in irreversible loss of visual function and impairment in everyday visual tasks. The experimental studies described in this thesis primarily aim to investigate the performance of people with glaucoma on search and other visual …
-
Optic Nerve Head Image Analysis for Glaucoma Progression Detection
… diagnosed the glaucoma patient will spend the rest of their life receiving treatment in managed clinical care. In the glaucoma clinic, retinal and optic nerve head (ONH) imaging can be used to help the clinician to manage patient treatment appropriately. By providing high resolution images of …
-
Improving measurements in perimetry for glaucoma
… a leading cause of visual impairment and, if untreated, irreversible blindness. Perimetry is the clinical tool for assessing the functional ‘seeing’ part of the field of view (visual field) and is widely used in the detection and clinical monitoring of glaucoma. These measurements rely on a …
-
The multifocal visual evoked cortical potential in visual field mapping: a methodological study.
… visual evoked cortical potential (mfVECP) presents several technical challenges. Signals are small, are influenced by a number of sources of noise and waveforms vary both across the visual field and between subjects due to the complex geometry of the visual cortex. Together these factors …
-
Trends and health economic aspects of service delivery of glaucoma
… group of optic neuropathies characterised by progressive irreversible loss of visual function. Within this thesis, a health economic model was constructed to map service provision from diagnosis considering two competing strategies: the current practice of annual visual field (VF) monitoring …
-
Studies on real world visual field data in glaucoma
… is a leading cause of blindness. As a progressive condition, it is important to monitor how the visual field (VF) changes over time with perimetry in preventing vision from deteriorating to a stage where quality of life is affected. However, there is little evidence of how clinical …
-
Studies of normal and deficient colour vision with relevance to occupational environments
… colour vision in visually demanding, colour-related tasks that are often safety-critical and aim to improve our understanding of how congenital deficiencies can affect the processing of colour signals and the corresponding changes in visual performance. The first study compares the colour …
-
Reclaiming the periphery: Kinetic perimetry in patients with glaucoma
… test in glaucoma patients. Short test durations are achieved by focusing on a central region, which constitutes ~20% of the visual field. However, ignoring the periphery may sacrifice information on how patients are affected functionally. Peripheral vision is important for guiding attention, …
-
Investigation of plenoptic imaging systems: a wave optics approach
Conventional imaging devices only capture a part of the total information carried by the light. A new generation of imaging devices, plenoptic systems, use an array of micro lenses to codify the light coming from an object into a four dimensional function called the light field. The final image is …
-
A study of mechanisms for discomfort glare
The presence of a bright light source in the visual field, particularly when viewed against a dark background, can generate a form of discomfort, which is often described as ‘discomfort glare’. The mechanisms for discomfort glare remain poorly understood, even after 50 years of multidisciplinary …
-
Ethnic differences in the spatial distribution of macular pigment and its association with foveal anatomy
Macular pigment (MP) at the centre of the retina is thought to serve a protective function shielding the photoreceptors from damaging effects of blue light. The amount of MP and its spatial density distribution across the macula i.e. its spatial profile varies among individuals. Lower levels of MP …
-
Spatial and temporal aspects of visual performance in relation to light level and normal aging
The research contained in this thesis describes three studies designed to investigate the ability of the observer to detect stimuli defined by changes in luminance in space and/or time in mesopic conditions, including contrast sensitivity, temporal flicker sensitivity and visual acuity. The first …
-
Glistenings in Intraocular lenses and their effect on forward light scatter; an in vitro study
Introduction. Glistenings are fluid-filled inclusions in the polymer matrix of an intraocular lens (IOL). Acting as refractile particles they may contribute to a reported high level of forward light scatter. However, several studies have reported that there is no significant correlation with a …
Page 1 of 2