Optical And Neural Limits Of Visual Performance In Myopia
Funder
National Health and Medical Research Council
Funding Amount
$191,902.00
Summary
Short-sightedness (myopia) is one of our most common eye problems, affecting approximately 20% of people. It is usually due to the eye becoming too long for its power. While we can correct short-sight with contact lenses, spectacles and more recently refractive surgery, recent evidence shows that the vision of corrected myopes is poorer than that of people who have good distance vision without the need for an optical correction. This reduction is present even when the optical minification of spe ....Short-sightedness (myopia) is one of our most common eye problems, affecting approximately 20% of people. It is usually due to the eye becoming too long for its power. While we can correct short-sight with contact lenses, spectacles and more recently refractive surgery, recent evidence shows that the vision of corrected myopes is poorer than that of people who have good distance vision without the need for an optical correction. This reduction is present even when the optical minification of spectacle lenses is taken into account (the lenses used to correct short-sightedness make objects look smaller). It is possible that the anatomical changes to the eye that occur in short-sightedness are the cause of the reduced vision. Even if the optics can be fully corrected with refractive surgery, as is now being proposed, this may not result in excellent vision. The anatomical changes may occur in different parts of the eye and depending on where they occur the nature of the visual reduction will vary. The location of the retinal changes may also be important in terms of eventual pharmacological treatments for short-sightedness. In addition, the significance of the visual reduction, in terms of its effect on the functioning of short-sighted people, e.g. ability to perform under less than optimal visual conditions such as in the presence of glare or reduced light levels, is not known. We plan to investigate this by identifying the optical and neural contributions to visual performance in short-sighted people.Read moreRead less
Age Related Changes In The Optics Of Adult Human Eyes
Funder
National Health and Medical Research Council
Funding Amount
$199,437.00
Summary
Vision is limited by both optical and retinal-neural factors. Our understanding of the optical structure of the human eye is limited, partcularly for the refractive index gradient of the lens, let alone how these change with age. This understanding is needed if we are to accurately predict or assess the long-term effects of refractive surgical procedures or ophthalmic prostheses on vision. In this project, we aim to substantially improve our understanding of the optical properties of the eye by ....Vision is limited by both optical and retinal-neural factors. Our understanding of the optical structure of the human eye is limited, partcularly for the refractive index gradient of the lens, let alone how these change with age. This understanding is needed if we are to accurately predict or assess the long-term effects of refractive surgical procedures or ophthalmic prostheses on vision. In this project, we aim to substantially improve our understanding of the optical properties of the eye by 1) developing methods for measuring these quantities and then applying the methods to investigate how these properties vary with age and focussing, and 2) determine the optical contribution to reduction in visual performance with increasing age. Our research will be used to determine norms for growth and aging patterns in the normal human eye, particularly the lens. It will yield significant outcomes through 1. determination of the long-term success of custom refractive surgery aimed at improving vision by eliminating the ocular aberrations, and 2. indicating the potential improvement in ocular performance provided by artificial intraocular lenses or any other type of correction.Read moreRead less
Improved Identification Of At-risk Brain Tissue In Patients With Stroke
Funder
National Health and Medical Research Council
Funding Amount
$279,044.00
Summary
Stroke is one of the most frequent causes of death and the major cause of adult neurological disability. Diagnostic tools to improve its management are therefore crucial. This project is dedicated to improving the magnetic resonance imaging techniques for measuring blood flow to the brain, and to applying these to patients who have had a stroke. Improved methods will enable better prediction of tissue outcome following stroke, thus enabling optimal early management decisions to be taken.
Acute Stroke: Imaging The Ischaemic Penumbra With Perfusion CT
Funder
National Health and Medical Research Council
Funding Amount
$243,000.00
Summary
The burden of stroke is large. Clot-dissolving medication (thrombolysis) may dramatically improve the outcome of many patients with severe stroke by unblocking the affected brain artery. However, very few patients receive this medication, as the current approval is restricted to treatment within 3 hours of stroke onset. The major aim of thrombolysis is to rescue brain tissue with reduced blood flow (the ischaemic penumbra) from becoming irreversibly damaged (infarcted). The penumbra progressivel ....The burden of stroke is large. Clot-dissolving medication (thrombolysis) may dramatically improve the outcome of many patients with severe stroke by unblocking the affected brain artery. However, very few patients receive this medication, as the current approval is restricted to treatment within 3 hours of stroke onset. The major aim of thrombolysis is to rescue brain tissue with reduced blood flow (the ischaemic penumbra) from becoming irreversibly damaged (infarcted). The penumbra progressively becomes infarcted over the next 48 hours if blood flow is not restored by the blood clot in the brain artery being dissolved. Penumbral brain tissue cannot be identified with clinical assessment or standard CT scanning. New generation CT scanners are capable of assessing brain blood flow. Perfusion CT imaging (CTP) is well tolerated and time-efficient, and can be integrated into the brain CT scanning process performed on all stroke patients. Preliminary evidence suggests that CTP can distinguish between tissue that represents the ischaemic penumbra, and tissue that is already permanently injured. This project aims to validate the use of CTP in imaging the ischaemic penumbra. This will be based on testing the accuracy of CTP tissue signatures of the penumbra in predicting clinical outcome and final stroke size. This is the only national collaborative study planned worldwide for this relatively new but increasingly accessible imaging technique. The ability to rapidly identify under-perfused but still viable brain with CTP would add new and exciting management options to the routine emergency assessment of stroke patients. The results of this unique study could have a significant impact on the management of acute stroke worldwide. If validated, it is anticipated that CTP would be widely used to improve patient selection for stroke thrombolysis, especially in safely extending the time window so that a greater number of patients can be treated with better outcomes.Read moreRead less
Brain surgery for the treatment of epilepsy is associated with a risk of cognitive impairment. Avoidance of disabling post-operative impairments depends in large measure on our ability to predict and measure individual patterns of language lateralization prior to neurosurgical intervention. Typical patterns of lateralisation cannot be assumed in patients with epileptogenic lesions. There appears to be a consensus that atypical representation is more frequent in patients with epilepsy than it is ....Brain surgery for the treatment of epilepsy is associated with a risk of cognitive impairment. Avoidance of disabling post-operative impairments depends in large measure on our ability to predict and measure individual patterns of language lateralization prior to neurosurgical intervention. Typical patterns of lateralisation cannot be assumed in patients with epileptogenic lesions. There appears to be a consensus that atypical representation is more frequent in patients with epilepsy than it is in the normal population, and values above 20% are not unrepresentative Partial epilepsy arises from a region in the brain and spreads to involve other areas. This is contrasted with generalised epilepsy, which appears to arise all over the brain simultaneously. Partial epilepsy is often associated with lesions such as tumors or hippocampal sclerosis, and often seizures are intractable. Patients with partial epilepsy have a number of sources of brain damage in the language areas. Primary brain changes may be pre-existing, which means they pre-date the onset of habitual seizures. They may consist of a focal developmental abnormality (a malformation of cortical development) or may represent a general genetic predisposition to seizures. Therefore, partial epilepsy is not only associated with severe abnormalities in epileptogenic region but also with additional widespread abnormalities in both hemispheres. There is also evidence for a correlation of abnormalities with seizure frequency with some suggestion that the duration of epilepsy may also increase the degree of abnormality in the hemisphere. The neuronal conditions in language cortex that give rise to altered lateralisation in function are currently not known. The primary aim of this study is to understand reorganisation of the language system in epilepsy by using the current most sensitive non-invasive methods of assessing brain damage and brain function, using magnetic resonance imaging.Read moreRead less
Diagnostic And Prognostic Evaluation Of Diffusion Tensor Imaging And Cognitive Function After Traumatic Brain Injury
Funder
National Health and Medical Research Council
Funding Amount
$874,404.00
Summary
Traumatic brain injuries (TBIs) are a common cause of brain damage, leading to a variety of disabling cognitive problems. This study will evaluate the ability of new brain imaging techniques and cognitive tests to detect previously undiagnosed brain damage and to predict patient outcome following TBI in order to improve the health care and treatment of these patients. It will also examine the contribution of other factors (eg. injury type, age, pre-injury cognitive ability) to outcome.
Molecular Imaging Of Brain Tumour Therapeutic Efficacy
Funder
National Health and Medical Research Council
Funding Amount
$412,200.00
Summary
The prognosis for malignant brain tumour patients that do not respond to intial treatment strategies is very poor. The fact that many of these patients patients will not survive longer than 12 months post diagnosis underscores the need to make treatment management decisions in a timely manner. This project seeks to develop and validate non-invasive early molecular imaging biomarkers that can quantify treatment efficacy months before traditional measures of efficacy are valid.
Improving The Assessment Of Brain Tumour Treatment Outcome Using 18F-FDOPA PET-MRI Fusion
Funder
National Health and Medical Research Council
Funding Amount
$660,666.00
Summary
The mortality rate within the first year of diagnosis for high-grade brain tumours is approximately 80%. A major factor contributing to poor outcome measures is the limitation of current neuroimaging techniques. In a novel approach we propose to combine the information available from MRI and PET images to better define the extent of the tumour and provide markers of early treatment response. This improved diagnostic information should improve survival rates.
Neurocognitive Studies Of Brain Plasticity Associated With Surgical Treatment Of Arteriovenous Malformations
Funder
National Health and Medical Research Council
Funding Amount
$701,922.00
Summary
We will use state-of-the-art brain imaging methods to test whether specific brain areas which have been chronically starved of adequate blood supply can regenerate, informing debate about limits on brain plasticity. Arteriovenous malformations (AVMs) are longstanding defects which can cause thinking skills to 'migrate' to other brain regions in childhood without noticeable impact. Surgical correction allows a test of what happens to the previously inactive area: Does the area 'start to think'?