Characterising The Changes In Regulation Of Visual Contrast Sensitivity In Glaucoma.
Funder
National Health and Medical Research Council
Funding Amount
$337,600.00
Summary
Glaucoma is the second leading cause of blindness in developed nations. A recent study estimated the number of Australian's that will need regular visual examination in 2030 either because they have glaucoma or glaucomatous risk factors to be at least 800,000. As the ultimate aim of glaucoma treatment is to maintain vision, visual functional assessment is of paramount importance to glaucoma management . The current standard measure for the assessment of visual loss due to glaucoma is visual fiel ....Glaucoma is the second leading cause of blindness in developed nations. A recent study estimated the number of Australian's that will need regular visual examination in 2030 either because they have glaucoma or glaucomatous risk factors to be at least 800,000. As the ultimate aim of glaucoma treatment is to maintain vision, visual functional assessment is of paramount importance to glaucoma management . The current standard measure for the assessment of visual loss due to glaucoma is visual field testing. Regrettably, substantial damage to retinal ganglion cells (the primary neurons affected by glaucoma) is often present prior to the discovery of visual field loss using standard measures. Indeed studies have demonstrated that even 30-50% retinal ganglion cell loss may only manifest as a mild visual field deficit using current standard testing. This project will use novel techniques for exploring sight impairment in glaucoma, enabling a better understanding of the underlying neural damage. Our pilot work demonstrates that these methods can detect loss of sight in areas diagnosed as normal using standard visual field testing. The study will provide new technologies for the assessment of early vision loss due to glaucoma that may enable the detection of malfunction of retinal ganglion cells prior to their death. Such measures of neural malfunction are essential to establishing the efficacy of new pharmacological therapies (known as neuroprotective agents) for glaucoma aimed at keeping retinal ganglion cells alive and functioning. This project also has the potential to identify visual measures that have better capability for monitoring the progression of vision loss due to glaucoma. Early detection of glaucoma and its progression is essential so that treatment can be initiated or altered, slowing the progression of vision loss and its toll on both the individual and the community.Read moreRead less
A Functional Predictive Test For Age-related Macular Degeneration
Funder
National Health and Medical Research Council
Funding Amount
$532,500.00
Summary
Age-related macular degeneration (AMD) is the leading cause of blindness in our community. It is a progressive, late onset disease affecting central vision. Signs of disease are present in 15% of the population over 50 years with severe visual loss affecting increasing numbers in each subsequent decade. By 90 years 25% of people will have lost significant vision. There is no prevention, and treatment options are limited and have little impact on the rates of blindness. AMD causes enormous person ....Age-related macular degeneration (AMD) is the leading cause of blindness in our community. It is a progressive, late onset disease affecting central vision. Signs of disease are present in 15% of the population over 50 years with severe visual loss affecting increasing numbers in each subsequent decade. By 90 years 25% of people will have lost significant vision. There is no prevention, and treatment options are limited and have little impact on the rates of blindness. AMD causes enormous personal costs and places a massive burden on health resources. The high prevalence, anticipated increase in the ageing population and the limited treatment options, highlight the urgency with which research is required. The early clinical signs of AMD are yellow deposits called drusen, in the central retina (macula) and alteration in retinal pigmentation. As AMD progresses the macula is damaged either through atrophy (holes) or by growth of blood vessels. Currently, clinically accessible information about drusen and pigmentary changes are used to grade the severity of disease and predict the risk of progression to vision loss. This at risk group is recruited into prevention and intervention studies looking for new interventions. Such scoring of clinical characteristics currently underpins all clinical trials and epidemiological research in AMD. However this scheme is not without limitations, and results in an inexact correlation between clinical appearance and risk of blindness. We believe that a test of retinal function, (ability to see in the dark, to detect a faint light), will provide a better correlation for identifying patients at high risk of vision loss. We aim to test various aspects of retinal function (in both the light and dark and for moving and stationary objects) in subjects with early clinical signs of AMD, to identify parameters that will be more sensitive and specific predictors of risk of progression to visually devastating complications of AMD.Read moreRead less
Properties Of Human Photoreceptors Measured Using A Scanning Laser Ophthalmoscope To Illuminate And Image The Retina
Funder
National Health and Medical Research Council
Funding Amount
$352,000.00
Summary
Vision begins with the detection of light by the rod and cone photoreceptors in the retina lining the interior of the eye. Although much is already known about the way that light is detected and the signals are processed, a great deal remains to be learned. Some of the outstanding questions could be answered using modifications to a relatively new instrument called a scanning laser ophthalmoscope (SLO) which provides images of the interior of the eye. The aims of this project are to develop a mo ....Vision begins with the detection of light by the rod and cone photoreceptors in the retina lining the interior of the eye. Although much is already known about the way that light is detected and the signals are processed, a great deal remains to be learned. Some of the outstanding questions could be answered using modifications to a relatively new instrument called a scanning laser ophthalmoscope (SLO) which provides images of the interior of the eye. The aims of this project are to develop a modified SLO, which is able to measure the levels of visual pigment (rhodopsin) in the living eye, which is also able to deliver visual stimuli to the eye, and which finally is extended to use adaptive optics so that it can image and excite individual cone photoreceptors. Using this device, we will be able to measure the regeneration of visual pigment following exposures to intense illumination, to help explain the slow recovery of visual sensitivity after intense light. We will also be able to measure the electroretinogram (ERG) from localized retinal areas, to investigate how the properties of the photoreceptor cells vary across the retina. And finally we will be able not only to visualize the individual tiny cone photoreceptors, but also to stimulate them selectively, so that we can determine the responses of the different classes of cone (red-, green-, and blue-sensitive cones) in the living human eye.Read moreRead less
DISSECTING THE GENETICS OF GLAUCOMA AND ITS RISK FACTORS USING A TWIN STUDY.
Funder
National Health and Medical Research Council
Funding Amount
$682,850.00
Summary
Glaucoma is one of the leading causes of blindness both in Australia (affecting 2-3% of the population) and worldwide. Glaucoma is often asymptomatic until it causes permanent loss of peripheral vision that precludes 10% of individuals with the condition from holding a driver's license. Around 50% of people with glaucoma are unaware that they have the condition; therefore better screening strategies are required. Genetic factors have been shown to contribute to glaucoma and our work has revealed ....Glaucoma is one of the leading causes of blindness both in Australia (affecting 2-3% of the population) and worldwide. Glaucoma is often asymptomatic until it causes permanent loss of peripheral vision that precludes 10% of individuals with the condition from holding a driver's license. Around 50% of people with glaucoma are unaware that they have the condition; therefore better screening strategies are required. Genetic factors have been shown to contribute to glaucoma and our work has revealed that 50% of people with glaucoma have a family history of the condition. Raised intraocular pressure (IOP) is a major contributing factor in glaucoma. Although there are some genes associated with high-pressure glaucoma, little is known about the heritability of IOP itself. Optic disc cupping is another important sign in the diagnosis and management of glaucoma, but again little is known of the inheritance of this feature. Twin studies, (comparing sets of identical twins with non-identical twins); allow us to estimate the relative contribution of genetic and environmental factors to disease states or physiological measurements. Although there have been small studies involving twins with glaucoma, it is unknown to what degree the basic parameters of glaucoma diagnosis such as IOP and optic disc characteristics are heritable. This project aims to conduct a large twin study into glaucoma and its associated ocular risk factors, including refractive error. We aim to identify genes that predispose to glaucoma, which will facilitate better screening for glaucoma in family members, and the general population, and ultimately leading to improved treatment.Read moreRead less
Heritable Influences In Experimental Retinopathy Of Prematurity
Funder
National Health and Medical Research Council
Funding Amount
$272,591.00
Summary
Retinopathy of prematurity is an eye disease of very premature infants who require neonatal intensive care. It is a major cause of childhood blindness world-wide. Disease is caused by the growth of abnormal blood vessels in the retina, at the back of the eye. Currently, management involves the repeated examination of premature infants by an eye doctor. The babies are anaesthetized for this examination. If early disease is detected, then the affected eyes are treated with a medical laser, to burn ....Retinopathy of prematurity is an eye disease of very premature infants who require neonatal intensive care. It is a major cause of childhood blindness world-wide. Disease is caused by the growth of abnormal blood vessels in the retina, at the back of the eye. Currently, management involves the repeated examination of premature infants by an eye doctor. The babies are anaesthetized for this examination. If early disease is detected, then the affected eyes are treated with a medical laser, to burn the abnormal blood vessels. This stops the growth of these vessels and can prevent the child from going blind. However, the laser treatment itself can damage the eye. Left untreated, early retinopathy of prematurity will disappear of its own accord in some babies, but because they cannot currently be distinguished from those who will develop severe disease, all babies with signs of disease are treated. Not every premature infant develops retinopathy of prematurity: an as-yet unknown genetic factor controls susceptibility to disease. We plan to investigate this genetic basis using laboratory rats. Raised under the same conditions that are used in intensive care nurseries, baby rats develop eye disease that is similar to retinopathy of prematurity. However, as with human babies, not every baby rat develops this eye disease. We have shown a heritable tendency to retinopathy in different strains of rat. We identify the genes and proteins that differ amongst rats with or without the eye disease. We predict that identification of the inherited factors for retinopathy of prematurity in rats will provide strong clues to similar factors in humans. Our ultimate goal is to develop a test which will identify those human babies who are at risk of developing blinding retinopathy of prematurity, so that treatment is not given unnecessarily. We also expect to discover new targets for treatment.Read moreRead less