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
INTRARETINAL OXYGEN CONSUMPTION AND THE PREVENTION OF HYPOXIA IN RETINAL ISCHEMIA
Funder
National Health and Medical Research Council
Funding Amount
$164,444.00
Summary
Adequate oxygen supply to the retina is critical for normal visual function. The oxygen is normally supplied by the blood flowing in the two circulations that support the retina. These are the choroidal circulation, lying behind the retina, and the retinal circulation, which supports the front half of the retina. The retinal circulation is particularly vulnerable to vascular disease and insufficient blood flow (ischemia). Vascular changes are involved in a wide range of retinal diseases which ar ....Adequate oxygen supply to the retina is critical for normal visual function. The oxygen is normally supplied by the blood flowing in the two circulations that support the retina. These are the choroidal circulation, lying behind the retina, and the retinal circulation, which supports the front half of the retina. The retinal circulation is particularly vulnerable to vascular disease and insufficient blood flow (ischemia). Vascular changes are involved in a wide range of retinal diseases which are currently responsible for the majority of new blindness in our community. The choroidal circulation is relatively robust, and offers a potential avenue for increasing oxygen delivery to the retina in the clinical management of ischemic retinal diseases. The feasibility of such an approach is strongly dependent on the oxygen requirements of the retina, and how this is influenced by retinal ischemia. We plan to find out how much oxygen is consumed by the many different layers within the retina under normal conditions and then determine how this changes under ischemic conditions. We will then see if we can supply enough oxygen from the choroid by a combination of raising the oxygen content of the blood, increasing choroidal blood flow, and reducing the amount of oxygen used by the outer half of the retina. Our experiments will be done in laboratory rats, but the same principles are readily transferable to humans if they prove to be beneficial in protecting the retina from ischemic damage. Our study will also quantify the relationship between oxygen levels in the blood stream, and those in the different layers of the retina. This information may prove valuable in the treatment and the prevention of other retinal diseases where the manipulation of the intraretinal oxygen environment is an exciting new avenue of research.Read moreRead less