The discovery of a unique set of proteins behind glaucoma could lead to better diagnosis and treatment.
In glaucoma, elevated pressures inside the eyeball stress the optic nerve and nerve arms -- called axons that reach out to communicate with the brain. Over time, increased pressure can kill nerve cells and axons and decrease vision.
The pressure results from an imbalance in fluid production and loss. In a healthy eye, the fluid, called the aqueous humor, moves continually from the back to the front of the eye where it exits, mostly via a natural tract between the iris and cornea, first into spongy tissue near the cornea's base called the trabecular meshwork then into the venous system and back into the body.
In open-angle glaucoma, the most common type in US, the tract remains open but fluid still backs up and scientists suspect changes in the permeability of the trabecular meshwork may be to blame. Topical glaucoma treatments work by reducing fluid production or increasing outflow through a secondary drainage system, also near the front of the eye.
To get a better picture of what happens to the trabecular meshwork, Kathryn Bollinger, Medical College of Georgia clinician-scientist, examined tissues from the outflow tracts and trabecular meshwork of patients with and without glaucoma. She added TGF, a protein and inflammatory element known as a cytokine that is consistently found at high levels in patients with open-angle glaucoma. After comparing treated and untreated tissue, she found that TGF, resulted in a similarly unique protein pattern. Current therapies don't target TGF or its effects in the trabecular meshwork.
Next steps include identifying additional proteins expressed in glaucoma, determining the impact of the unique protein profile on the trabecular meshwork and clarifying TGF's normal role inside the eye, Bollinger said. She was reporting at the the Association for Research in Vision and Ophthalmology Annual Meeting April 30-May 6.
The MCG ophthalmologist received the 2010 ARVO/Alcon Early Career Clinician-Scientist Research Award for the study.