Glaucoma is most commonly caused when poor fluid drainage causes pressure to build inside the eye, leading to irreversible optic nerve damage and vision loss. Left untreated, glaucoma leads to blindness. A 2020 study, however, has given new hope to both researchers and patients. 

An investigative team at Vanderbilt University Medical Center (VUMC) discovered that when one optic nerve is damaged or under stress from fluid pressure, the optic nerve from the other eye supports the damaged one by transferring some of its stored energy.* 

How does this work?

While the study team is uncertain as to how the healthy optic nerve knows to jump into action, they do know that it helps by sending glycogen (a form of glucose) to the other eye through the optic chiasm. The optic chiasm is an X-shaped structure in the brain that’s formed where the optic nerves connect and cross, and glucose is the fuel that the neurons need to function.

In donating and depleting its energy stores, however, the healthy optic nerve becomes vulnerable to stress and more susceptible to disease and injury. David Calkins, Ph.D., vice-chair of the Department of Ophthalmology and Visual Sciences at VUMC and Director of the Vanderbilt Vision Research Center, stated that this isn’t necessarily bad news. 

“This is the first demonstration of metabolic resources being shared between the two eyes and optic nerves,” he said in a university news release. “This implies that a way to slow neurodegeneration generally would be to boost metabolic resources in the brain.”

How would they boost metabolic resources?

Calkins explained that this could be accomplished by reprogramming astrocytes—a type of cell found in the brain and spinal cord—to generate and store more glycogen and other energy sources, which can then be shared without leaving the sources vulnerable to attack. The reprogramming process is a form of gene therapy that has already been used effectively to reprogram neurons to combat other eye-related diseases.

According to Calkins, there may be even more cause to rejoice. The study findings, which were recently published in the Proceedings of the National Academy of Sciences, offer a potential new path in the treatment of not only glaucoma but also other neurodegenerative diseases, such as Alzheimer’s.

*Vanderbilt University Medical Center. (2020, July 22). Study Points to Potential New Approach to Treating Glaucoma and Alzheimer’s Disease. Eyewire News. https://eyewire.news/articles/study-points-to-potential-new-approach-to-treating-glaucoma-and-alzheimers-disease/

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