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Advanced Imaging for Glaucoma (NIH R01EY013516)Glaucoma is the second leading cause of blindness in the U.S. The diagnosis and monitoring of glaucoma remains challenging. Although intraocular pressure (IOP) is an important risk factor, it is not a sensitive diagnostic measurement. Half of the individuals with glaucoma had normal IOP on a single visit, according to the Baltimore Eye study. Visual field (VF) defects occur only in later stages of the diseases and are difficult to measure reproducibly. Although expert grading of optic disc appearance could detect glaucoma even before visual field defects in clinical studies, the graders need to be well trained and the grading is subject to significant inter-observer disagreement. Quantitative imaging of the eye structures damaged by glaucoma could provide automated objective data for the diagnosis and tracking of glaucoma. Since medical and surgical treatments of glaucoma both entail significant costs and risks, better clinical decision making based on more reliable objective measures of disease status and progression could greatly benefit patients with glaucoma and those at risk for developing the disease.
The Advanced Imaging for Glaucoma (AIG) project combines a 5 year longitudinal clinical study with efforts to improve quantitative imaging technologies, including optical coherence tomography (OCT), scanning laser polarimetry and scanning laser tomography.
The goal of this partnership is to develop advanced imaging technologies that can improve the detection and management of glaucoma. Currently-employed advanced imaging devices include optical coherence tomography, scanning laser polarimetry and scanning laser tomography. The imaging technologies will be evaluated in a longitudinal 5-year clinical trial. Study subjects will include patients with normal eyes, patients with glaucoma, and individuals at risk for developing glaucoma.
The clinical study includes normal, glaucoma suspect (GS), pre-perimetric glaucoma (PPG) and perimetric glaucoma (PG) subjects. The study sets and validates criteria for initial diagnosis and progression detection. The study has validated the clinical value of technological improvements made by device manufacturers, such as the GDx-ECC algorithm for enhanced scanning laser polarimetry. The study will show how anatomic abnormalities measured by advanced imaging techniques can be used to predict future disease progression and loss of visual field.
The technology development program includes very high speed Fourier-domain OCT (FD-OCT), Doppler OCT, polarization-sensitive OCT (PS-OCT) and multi-angle OCT. The study has succeeded in using high performance FD-OCT to measure the optic disc, peripapillary nerve fiber layer (NFL) and macular ganglion cells. The pattern of ganglion cell loss has proven valuable, not only for glaucoma diagnosis, but also for the characterization of other optic neuropathies. We also demonstrated reproducible total retinal blood flow measurement with Doppler FD-OCT, an important advance that may allow assessment of poor blood flow as a risk factor for the progression of glaucoma and retinal vascular diseases.
Three centers will be conducting the AIG clinical study, and four basic science and engineering centers will develop the advanced imaging instruments and conduct laboratory studies on glaucoma.
The three clinical centers are:
? University of Miami, Bascom Palmer Eye Institute, Miami, Florida; ? University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; and ? University of Southern California, Doheny Eye Institute, Los Angeles, California.
The four basic science and engineering centers are:
? Case University, Cleveland, Ohio; ? Duke University, Durham, North Carolina; ? University of Miami, Bascom Palmer Eye Institute, Miami, Florida; and ? University of Southern California, Doheny Eye Institute, Los Angeles, California.
Sub-projects for AIG Study (image processing and analysis) ? Automatic image analysis for optical coherence tomography ? Diagnosis of glaucoma with optical coherence tomography ? Grading of diabetic macular edema with optical coherence tomography ? Retinal disease diagnosis and Fourier domain optical coherence tomography ? Fast rendering of 3D optical coherence tomography images ? Automatic blood vessel detection for Doppler blood flow measurement. RSS |
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