Intraocular pressure (IOP) reduction is the only treatment proven to slow glaucoma, one of the leading causes of blindness worldwide.  IOP-related connective tissue stress and strain is thought both to cause direct mechanical damage to the retinal ganglion cell axons passing through the lamina cribrosa and, most relevant to this project, to reduce the capillary blood flow in and around the optic nerve head. In fact, significant evidence shows that glaucoma patients have underlying vascular abnormalities with poor autoregulation that make them predisposed to unstable ocular blood flow and thus glaucomatous damage. While some prior studies using precursor technology have demonstrated some improvement in large vessel ocular blood flow parameters after IOP reduction, until recently, we have never had the capability to visualize the microcirculation around the optic nerve head. Optical coherence tomography angiography (OCTA) now affords us the opportunity to determine if peripapillary microcirculation improves after IOP reduction treatment in glaucoma, and which ocular anatomic and systemic vascular factors may alter this microcirculation change. This study will provide important data for the growing literature on the vascular mechanisms underlying glaucoma and fill a critical void in knowledge regarding the effects of our glaucoma treatments on retinal microcirculation, something often overlooked in the current design of OCTA glaucoma studies. This important study will provide the necessary pilot data for my application of a larger NIH-funded grant to conduct a larger longitudinal study of glaucoma patients undergoing various forms of IOP reduction treatment. OCTA has the great potential to allow us to improve our ability to identify glaucoma earlier and possibly even develop new therapeutic targets that improve ocular blood flow and prevent blindness related to the disease.

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