A team of researchers headed up by Emory Eye Center researcher, Andrew Feola PhD, is investigating a hormonal link to glaucoma that could open doors to more effective treatment and prevention options. Under the auspices of a 5-year, $1.25 million National Institutes of Health grant and a 5-year, $800,000 Veterans Administration grant, Feola, an assistant professor in the Emory Medical School, is probing the connection between estrogen deficiencies and glaucoma - the leading cause of irreversible blindness in the world.
"A majority of glaucoma patients are female, so this is very much a womens health issue, said Feola, whose research combines training in hormones, biomechanics, and computational modeling with visual function and optic nerve head imaging.
"But its found that the risk of developing glaucoma in both men and women may be linked to mutations in estrogen receptors and polymorphisms in the estrogen metabolic pathway. This research could widen our understanding of that link, which will benefit both genders."
The NIH grant supports Feolas investigation of how intraocular pressure (IOP) - a known risk factor for glaucoma - is affected by menopause relative to natural aging. Modest elevations in IOP are linked to the onset of menopause, when estrogen levels begin to decrease. And estrogen-based hormone therapy has been shown to reduce IOP.
"There is a lot of data suggesting that the age of menopause, menopause itself, and a persons estrogen levels influence glaucoma risk by increasing or decreasing the IOP, but the mechanisms are still unknown," explains Feola.
Researchers in the NIH project will focus in on the possibility that altered estrogen levels impact aqueous outflow resistance, which correlates with IOP. They hope to understand the degree that the eye becomes more resistant to the outward flow of fluid. Researchers will also examine how the regulation of this outflow is controlled by trabecular meshwork (TM), a section of tissue located around the base of the cornea.
"We are hypothesizing that menopause increases IOP through the stiffening of different segments of the TM," he said.
The Veterans Administration grant will allow researchers to focus on how estrogen deficiency alters ocular biomechanical properties. Researchers will also observe a case of experimental glaucoma to see how estrogen deficiency impacts the process of vision loss, and, conversely, whether estrogen therapy is protective in both male and female rats.
"This treatment could complement current glaucoma treatments to help slow the progression of vision loss in glaucoma," Feola explained.
Before joining the EEC research staff in the fall of 2021, Andrew Feola worked as a research biologist at the Atlanta VA Medical Center and as a research scientist in the School of Biomedical Engineering at Georgia Institute of Technology/Emory University. He earned his bachelors and doctoral degrees from the University of Pittsburgh, where his graduate research focused on the biomechanical properties of pelvic tissues at different points in pregnancy, postpartum and hormonal status.
-Kathleen E. Moore