Currently, the main research focus in the Feola lab is to investigate visual disorders from a Women’s Health Perspective. Our main research area is glaucoma, and identifying sex-specific risk factors for this disease. In addition, Dr. Feola works on understanding how traumatic brain injury (TBI) impacts long-term visual and cognitive function. He is also excited to develop and explore new research projects.

Anatomy of the Eye

Figure 1: Schematic of ocular anatomy. A) Depicts a drawing of the eye with several key structures identified and intraocular pressure (IOP) acting within the eye.¹ Our main interest is to understand how IOP, tissue mechanical properties, and intracranial pressure (ICP) impact deformation at the optic nerve head (highlighted in blue). B) Is a histology section of the optic nerve head.² Here, the visual information translated by the retina along the axons of retinal ganglion cells (RGCs). These axons exit the posterior eye, pass through the lamina cribrosa, and form the optic nerve – which relays the visual information to the brain. C) An enface view the lamina cribrosa shows its complex structure of collagen fibers spanning the scleral canal opening.

Background: Glaucoma

According to the World Health Organization, glaucoma is the largest cause of irreversible blindness worldwide – affecting over 70 million individuals. Glaucoma is characterized by the loss of retinal ganglion cells (RGCs) – cells that relay visual information from the retina to the brain.

Figure 2: The NEI estimates the number of people in the U.S. with glaucoma to increase by 2050. On the right you can see an example of normal vision compared to what a person suffering from glaucoma may be able to see.

Menopause and Glaucoma

Menopause is a major life event for women (Figure 3) and tissues all over the body including bone, heart, brain and pelvic floor. Women typically enter menopause at 51 years of age and roughly 6,000 women become post-menopause each day. Recent works have identified that early menopause or an estrogen deficiency may increase the risk of developing glaucoma, while other studies have shown that menopause is associated with modest changes in eye pressure (IOP). Our goal is to explore how age and menopasue may play a sex-specific risk factor for glaucoma and other ocular diseases.

a. We know menopause affects tissues throughout the body. A focus of our research is how age and menopause impacts the eye and risks associated with glaucoma. b. The age a woman enters menopause influences the risk of developing glaucoma.

Our work on Menopause in Glaucoma:

We are currently investigating how menopause contributes to the etiology of glaucoma. Our goal is understand how age and menopause influence ocular tissue biomechanics. We also aim to determine why menopause exacerbates visual impairments in animal models of glaucoma and evaluate potential treatments to preserve visual function in experimental glaucoma after menopause.

Figure 3. In vivo imaging of the retina in an animal with experimental glaucoma. On the left you can see the retina at baseline while the right image clearly shows cupping of the ONH after 4 weeks of experimental glaucoma.

Developing Modeling of Glaucomatous Changes:

Figure 4: Tissues delineated using a 3D histomorphometric approach. The right illustrates the geometric model developed from these tissue delineations. The bottom panel displays the higher amount of deformation in the eye with experimental glaucoma compared to its contralateral control.

It is known that remodeling of the ocular tissues occurs in glaucoma. We currently are developing multiple computational models to better understand deformation at the ONH influenced by the tissue mechancial properties, various pressure loads, choroidal swell, anatomy, and menopause. For example, is poorly understood what changes occur in early vs. late glaucoma. In collaboration with Drs. Ross Ethier, Claude Burgoyne, and Hongli Yang we aim to use finite element modeling to characterize the ONH biomechanical properties of normal and experimental glaucomatous eyes. Using in vivo imaging we seek to determine deformation of the ONH in response to changes in IOP and develop specimen-specific models of normal and glaucomatous eyes.

¹National Eye Institute
²Michigan Histology and Virtual Microscopy