Method for accurate retinal oxygen metabolic rate extraction

PROJECT SUMMARY DR is a secondary complication of diabetes and a leading cause of blindness in the world Although it is well known that DR is driven by ischemia the current grading of DR severity is based only on structural alterations such as the presence of abnormal retinal microvasculature in non proliferative DR and angiogenesis in proliferative DR As a result when their diagnosis is first received most patients have already suffered from irreversible retinal functional impairment DR develops through progressively increasing capillary non perfusion leading to insufficient blood supply to meet the metabolic demand of the inner retinal neurons This causes retinal ischemia which activates signaling pathways that promote angiogenesis and herald the proliferative phase of retinopathy If not managed in a timely fashion proliferative DR can ultimately lead to blindness Therefore non invasive imaging of rMRO should improve our understanding of DR pathophysiology as well as significantly enhance our ability to diagnose and manage high risk DR Currently laser panretinal photocoagulation PRP remains the standard of care intervention for proliferative DR while anti VEGF therapy is being aggressively explored as an alternative In these treatments the goal is to presumably reduce the overall retinal oxygen demand and ameliorate retinal ischemia or suppress the pathological angiogenesis However the exact mechanisms of both PRP and anti VEGF effects have yet to be confirmed as there are no human studies that document rMRO before and after these treatments Hence the failure of treating proliferative DR patients can only be gauged by monitoring the recurrence of angiogenesis development of vitreous hemorrhage or progressive retinal tractional detachment all of which are associated with significant and occasionally permanent vision loss Therefore non invasive monitoring of rMRO has the potential to significantly improve the management of proliferative DR Prof Hao F Zhang s group at Northwestern University demonstrated in that visible light optical coherence tomography vis OCT can accurately quantify retinal sO and blood flow In the Zhang lab further confirmed that vis OCT can accurately quantify rMRO noninvasively in various rodent models of retinal ischemia and vis OCT is safe for human use Therefore vis OCT is the ideal candidate to investigate the role of rMRO dysregulation in early development progression and management of DR Collaborating with the Zhang lab Opticent Health s goal is to translate vis OCT from bench to bedside and to provide physicians with advanced clinical tools that can accurately and rapidly quantify rMRO in patients Given the fact that vis OCT is new and there has been limited clinical studies using vis OCT the crucial next step is to overcome obstacles that prevent vis OCT from being smoothly integrated with clinical practices and to examine vis OCT s clinical impact The proposed work addresses this need by developing robust algorithms to enable photographers with limited knowledge in optics and data processing to quickly and reliably measure patient s rMRO PROJECT NARRATIVE Significant improvement in clinical management of diabetic retinopathy will be possible if it s earliest pathological alterations can be detected and thoroughly understood Advanced noninvasive technologies to quantitatively image retinal oxygen metabolism may provide such a possibility This project seeks to develop robust algorithms to enable photographers with limited knowledge in optics and data processing to quickly and reliably measure patient s rMRO which is critical to the management of vision threatening diabetic retinopathy in patients