Aqueous Humor Oxidative Stress Markers in Glaucoma
Principal Investigator
Project Goals
Our proposed study will examine the aqueous humor, the fluid in the front of the eye, of patients who are undergoing eye surgery. We will measure both a byproduct (hydrogen peroxide) and a protectant (ascorbic acid) of oxidative damage, as well as oxygen levels in different parts of the front of the eye. By aiding in further understanding of this oxidative mechanism of glaucoma damage, it may lead to innovative therapies for this devastating condition.
Project Summary
Glaucoma, the second leading cause of blindness worldwide, is characterized by damage to the optic nerve which transmits visual information from the eye to the brain. Most cases are associated with increased eye pressure and decreased outflow through the drainage meshwork in the front of the eye. Current theories suggest that this age-related disease, as well as other eye conditions like cataract and macular degeneration, may be related to oxidative damage, toxic effects of excess oxygen forming harmful molecules called free radicals. Our proposed study will examine the aqueous humor, the fluid in the front of the eye, of patients who are undergoing eye surgery. We will measure both a byproduct (hydrogen peroxide) and a protectant (ascorbic acid) of oxidative damage, as well as oxygen levels in different parts of the front of the eye. By aiding in further understanding of this oxidative mechanism of glaucoma damage, it may lead to innovative therapies for this devastating condition.
Publications
Siegfried, C.J., Shui, Y.B., Wilkins, M.A., Beebe, D.C. Oxidant distribution and antioxidant protection in patients with glaucoma and cataract. Accepted for presentation at the 2008 Annual Meeting of the Association for Research in Vision and Ophthalmology. [conference abstract]
Siegfried CJ, Shui Y-B, Wilkins MA, Beebe DC (2008) Oxidant distribution and antioxidant protection in patients with glaucoma and cataract. Poster presentation, 2008 Annual Meeting of the Association for Research in Vision and Ophthalmology. [conference abstract] (This study reports our techniques of measurement of oxygen levels in the anterior chamber of human eyes in vivo and our preliminary data suggesting an oxygen gradient.)
Siegfried CJ, Shui Y-B, Wilkins MA, Holekamp NM, Hou JH, Bai F, Beebe DC (2009) Oxygen levels and distribution in the anterior chamber: Impact of cataract surgery and vitrectomy. Paper presentation, 2009 Annual Meeting of the Association for Research in Vision and Ophthalmology. [conference abstract] (This study reports our observations of the impact of cataract surgery and vitrectomy on the balance of oxidation in the human eye, with descriptions of a new physiologic correlation with an important yet poorly understood risk factor for glaucoma, central corneal thickness.)
Hou JH, Shui Y-B, Shetty SS, Siegfried CJ, Holekamp NM, Beebe DC (2009) The biochemistry of ascorbate-dependent oxygen consumption in human vitreous. Poster presentation, 2009 Annual Meeting of the Association for Research in Vision and Ophthalmology. [conference abstract] (This study evaluates a variety of biochemical reactions with ascorbate and catalase to further our understanding of this complex system.)
Siegfried CJ, Shui Y-B, Bai F, Holekamp NM, Beebe DC. (2010) Glaucoma Risk Factors and Intracameral Oxygen Levels. Poster presentation, 2010 Annual Meeting of the American Glaucoma Society. [conference abstract] (This study reports our observations of the correlations of oxygen levels with glaucoma risk factors of central corneal thickness, post-vitrectomy status, and African descent.)
Bai F, Lei P, Shui Y-B, Gupta R, Holekamp N, Siegfried C, Beebe D (2010) Differences in Ascorbate Distribution and Oxygen Consumption Between the Eyes of Humans and Other Animals. Poster presentation, 2010 Annual Meeting of the Association for Research in Vision and Ophthalmology. [conference abstract] (This study notes important differences between humans and other species in the ratios of ascorbate levels in the anterior versus posterior segment of the eye.)
Siegfried CJ, Shui Y-B, Bai F, Wilkins MA, Holekamp NM, Beebe DC. (2010) Racial Differences of Oxygen Levels in the Human Ocular Anterior Segment In Vivo. Poster presentation, 2010 Annual Meeting of the Association for Research in Vision and Ophthalmology. [conference abstract](This study focuses on the significantly higher levels of oxygen in all areas of the anterior segment in African-American patients compared with Caucasians.)
IOVS paper; Oxygen Distribution in the Human Eye: Relevance to the Etiology of Open Angle Glaucoma after Vitrectomy Carla J. Siegfried1, Ying-Bo Shui1, Nancy M. Holekamp1, 2, Fang Bai1, David C. Beebe1, 3 submitted as an addendum to her final progress report 6/1/2010. [PMID: nd][link not available]
First published on: June 11, 2008
Last modified on: November 24, 2024