The Blood-Retinal Barrier - Modelling Mechanisms For Maintenance, Breakdown And Repair
Funder
National Health and Medical Research Council
Funding Amount
$394,310.00
Summary
We believe that breakdown of the barrier that separates the delicate nervous tissue of the eye from the bloodstream, the blood-retinal barrier, may be an early event in the development of age-related macular degeneration (AMD), now overall the commonest cause of blindness in Australia. We have recently demonstrated with the first scientific clinical trials to be conducted in the world that an injection of steroid into the jelly of the eye, or vitreous , of the steroid triamcinolone slows the gro ....We believe that breakdown of the barrier that separates the delicate nervous tissue of the eye from the bloodstream, the blood-retinal barrier, may be an early event in the development of age-related macular degeneration (AMD), now overall the commonest cause of blindness in Australia. We have recently demonstrated with the first scientific clinical trials to be conducted in the world that an injection of steroid into the jelly of the eye, or vitreous , of the steroid triamcinolone slows the growth of abnormal blood vessels in patients with wet AMD. In the current project, Prof Nick King, a cell biologist and viral immunologist, will collaborate with Dr Michelle Madigan, A-Prof Jan Provis, both experts in experimetnal AMD, and A-Prof Mark Gillies, a clinician-scientist specialising in AMD, to study how the treatment works using established animal and laboratory models of a damaged blood retinal barrier. We will be particularly interested in processes which are thought to critical in the development these diseases. We will also study newly described processes by which the junctions that seal the cells of the barrier together come apart. We will be interested not just in the cells that make the barrier, but also the effect of nearby cells that are thought to contribute to it. These studies will provide a solid foundation for the rationalisation of steroid treatment for AMD which can be expected to result in improved outcomes for our patients. The studies may also provide insights into how other barriers malfunction, such as the blood brain barrier which breaks down in Alzheimer s disease and multiple sclerosis.Read moreRead less
The GABAergic System In Eye Growth Control And Myopia
Funder
National Health and Medical Research Council
Funding Amount
$318,142.00
Summary
Shortsightedness (myopia) is the most common visual disorder. High myopia is associated with an increased risk of eye diseases. Current treatments do not stop myopia developing or decrease the associated risk of eye disease. The continued worsening of myopia is very concerning. A safe effective treatment that can either prevent myopia or stop its progression to extreme levels is needed. We have data showing that GABA ergic drugs modify myopia. This proposal will determine the mechanisms.
Identifying Novel Disease Genes In Abnormalities Of The Eye
Funder
National Health and Medical Research Council
Funding Amount
$123,454.00
Summary
The macula is located in the centre at the back of the eye and is essential for detailed and colour vision. There are familial forms of macular abnormalities and many elderly patients suffer from age-related macular degeneration. The gene function that is critical for the maintenance of a healthy macula is not fully known. In this project, a novel process in maintaining macular health will be investigated to identify the underlying genetic cause and associated functional defects.
The fovea is a specialized part of the retina which enables us to see fine detail. The fovea is characterised by an extremely high concentration of photoreceptor cells in a small, prescribed area to detect detail in the pattern of light reaching the retina. Each of these photoreceptor cells is connected to at least four other cells within the retina, which further refine the information coded by the photoreceptors. Because this circuitry involves so many cells, the retina has a tendency to be th ....The fovea is a specialized part of the retina which enables us to see fine detail. The fovea is characterised by an extremely high concentration of photoreceptor cells in a small, prescribed area to detect detail in the pattern of light reaching the retina. Each of these photoreceptor cells is connected to at least four other cells within the retina, which further refine the information coded by the photoreceptors. Because this circuitry involves so many cells, the retina has a tendency to be thick at the specialized area. However, in development the cells connected to the foveal photoreceptors move away from the central concentration of photoreceptors, still keeping their contacts with them. This results in thinning of the retina locally, so it has a volcanoe-like formation at the fovea, in which photoreceptors are concentrated within the crater and the displaced cells are accumulated on the rim. The events which trigger these cell displacements that form the fovea are unknown. We propose to investigate growth factors which signal between the fovea and the developing blood supply, and the relationship between the formation of the fovea and neuronal activity. This study will provide a new perspective on factors which affect central visual function and its vulnerability to insult in premature infants and in aging.Read moreRead less
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
I am a medical retinal specialist who is involved in a spectrum of basic and clinical research into the cause, risk factors, prevention and treatment of age related macular degeneration, the most common cause of vision loss in Australia.
Development Of A Slit Scanning Laser Ophthalmoscope As A Screening Tool In Glaucoma Diagnostics
Funder
National Health and Medical Research Council
Funding Amount
$195,830.00
Summary
Glaucoma is typified by progressive optic disc cupping and loss of fibres with consequent characteristic field defects. Direct imaging of the retina and quantitative assessment of such images greatly increases early diagnosis of this blinding disease. The proposed device, a laser line scanning ophthalmoscope, could support non-invasive imaging to obtain 3-D information in a simple and cost effective way. This could provide objective clinical parameters to support the decision making process.
Cataract Surgery And Risk Of Age-related Macular Degeneration (AMD)
Funder
National Health and Medical Research Council
Funding Amount
$339,750.00
Summary
Cataract surgery currently ranks as one of the most frequently performed and successful surgical procedures in Australia (125,000 operations-year). Age-related macular degeneration (AMD) is the principal cause of moderate visual impairment and blindness, currently accounting for blindness in between 17,300 and 30,400 Australians. Past studies have not shown a definite relationship between cataract and AMD. Follow-up data from clinical case series and from two older population-based studies (the ....Cataract surgery currently ranks as one of the most frequently performed and successful surgical procedures in Australia (125,000 operations-year). Age-related macular degeneration (AMD) is the principal cause of moderate visual impairment and blindness, currently accounting for blindness in between 17,300 and 30,400 Australians. Past studies have not shown a definite relationship between cataract and AMD. Follow-up data from clinical case series and from two older population-based studies (the Beaver Dam and Blue Mountains Eye Studies) suggested that cataract surgery might increase the risk of subsequent development of AMD in operated eyes of older persons. Such an increased AMD risk in eyes after cataract surgery appears to be both short term (observation from clinical case series) and long term (evidence from population-based studies), and persists after taking into consideration age, sex, smoking, preexisting early stage lesions of the disease and correlation between both eyes. The proposed study is to follow a large number of older patients who are undergoing cataract surgery in Western Sydney Eye Hospital and in two ophthalmologists' private rooms. Rates of subsequent development of AMD will be compared between operated and non-operated eyes, and also between the surgical cohort and the Blue Mountains Eye Study cohort. We will document macular conditions carefully before and after surgery to exclude the possibility of confounding issues. We will also investigate whether the increased risk occurs in certain subgroups of patients at high risk of AMD. If an increased AMD risk from cataract surgery is confirmed in subgroups of patients, a modified clinical practice may be indicated, to maximize cataract surgery benefit and minimize the risk of vision loss from AMD after surgery. Changes may include additional patient information and consent about this risk, delayed cataract surgery within limits of visual function, and close postoperative follow up.Read moreRead less