This study aims to investigate whether a special type of cell, astrocytes, play a role in blood flow regulation in normal and pathological conditions in glaucoma. To achieve this goal, we will examine the bioactivities of astrocytes either under a microscope or directly within the eye with the tools developed in our laboratory. We will determine if the astrocytes are activated and help to keep the blood flow in the eye stable after we artificially change the blood flow. We will also determine if the blood flow is still stable after we interrupt a possible communication between the astrocytes and the blood vessels, so that we can learn how the astrocytes perform their regulatory work. Apart from the two innovative techniques that were developed in our laboratory and used in this study, the concept of how the astrocytes regulate the blood flow in the eye is unique. The anticipated results are expected to have a broad scientific impact on our understanding of the role of astrocytes in blood flow regulation in both eyes and other tissues of the body. Identification of the pathways will also allow us to develop possible therapeutic interventions to protect the ocular tissue from a lack of blood flow, progressive tissue damage and subsequent blindness caused by glaucoma.