Our Approach to Glaucoma Research

Elevated eye pressure, or intraocular pressure (IOP), is present in most forms of glaucoma when aqueous humor, the fluid that constantly bathes the front of the eye, cannot drain properly. Normally, the fluid drains through a spongy tissue known as the trabecular meshwork and flows into Schlemm’s canal, a ring-like passageway that then delivers it to the bloodstream. Blockages and other forms of resistance to aqueous humor outflow can raise eye pressure. Other factors are fluid volume and trabecular meshwork stiffness, which is reported to be 20 times higher in glaucoma than in healthy eyes. With critical National Glaucoma Research funding, grantees are unraveling novel mechanisms that regulate eye pressure and are exploring new ways to decrease stiffness and control eye pressure.

Ultimately, glaucoma threatens sight by damaging the optic nerve at the back of the eye, which carries light signals from the eye to the brain. Our knowledge of how and when glaucoma damages nerve cells remains imprecise. It’s linked mostly to chronic pressure increases inside the eye, referred to as elevated intraocular pressure (IOP), which may arise from the eye’s inability to drain fluid properly. National Glaucoma Research is funding studies on genetics, including studies addressing racial and ethnic disparities in disease incidence and onset. Other projects include developing more sensitive methods for studying onset and projects to develop new research models to promote a better understanding of glaucoma that may lead to new therapies.

Eye changes associated with glaucoma contribute to tiny blind spots, known as visual field defects, which can advance to vision loss and blindness. The speed and likelihood of this progression vary from person to person. Early diagnosis is key, and considerable progress has been made in eye imaging to detect the tiniest changes preceding glaucoma. National Glaucoma Research grantees are developing and leveraging new technologies to look at individual retinal ganglion cells (RGCs) of the eye and their nerve fibers, which carry light signals to the brain—a challenging task because RGCs are almost transparent and difficult to image. Scientists also are investigating disruptions in how cells communicate in glaucoma. The findings could result in earlier detection of and new ways to treat glaucoma.

Approved treatments for glaucoma primarily focus on lowering eye pressure. Many therapies involving eye drops or surgery lower eye pressure effectively, but most require skill and consistency to achieve results or, as with surgery, present recognizable risks.

More reliable treatments and new therapies to address the underlying causes of glaucoma beyond changes in intraocular pressure are needed. National Glaucoma Research grantees are working to develop drugs that will lower eye pressure and protect against nerve cell injury and death, as well as genome-editing approaches to restore the function of trabecular meshwork (a spongy tissue that drains fluids from the eye). Additional therapies include advancing stem cell transplantation, promoting lifestyle interventions, and identifying strategies to communicate genetic testing with at-risk individuals.

Unlike most cells in the body, which repair themselves, the nerve cells providing our vision don’t regrow once damaged. National Glaucoma Research is supporting research into ways of protecting cells threatened by advancing glaucoma and regenerating those cells after vision loss. The focus of these efforts is to replace and reconnect retinal ganglion cells (RGCs), the nerve cells that make up the optic nerve and carry visual signals over axons, long threadlike tails extending from the eye to the brain. This is a sophisticated undertaking, given how RGCs are wired into the brain. Another focus is to develop neuroprotective drugs and therapies that will help nourish and support fragile RGCs to ensure their long-term viability.