Glaucoma doesn’t just affect your eyes. Each eye has an intricate connection to the brain, and studies show that glaucoma shares multiple features with neurodegenerative diseases such as Parkinson’s, Alzheimer’s, and ALS (Lou Gehrig’s disease).*

Similarities and Differences

Glaucoma, Alzheimer’s, Parkinson’s, and ALS are all progressive diseases, and different areas of the brain are affected in each one. Age and family history are significant risk factors for all these conditions. 

What differentiates glaucoma from the others is that it specifically damages the optic nerve, which in turn affects other parts of your eye such as the retina. The retina and optic nerve (which is actually a bundle of nerves) are actually formed from part of the brain during early development. 

Why Glaucoma is a Brain Disease

Inside your eye, neurons called retinal ganglion cells collect visual information and pass it through the optic nerve to the rest of the brain. These ganglion cells are the first ones damaged in the glaucoma disease process. 

Due to the complex network of neural connections, ganglion cell death impacts surrounding nerves, even affecting the visual cortex, the part of the brain that helps us interpret what our eyes are seeing. 

How Treating Glaucoma as a Brain Disease Affects Treatment

Lowering intraocular pressure (or internal eye pressure) is still the primary approach to treating glaucoma. Focusing on the eye-brain connection instead of just on fluid drainage, however, opens the door to other, innovative forms of therapy such as neurotrophic factors. Neurotrophic factors are brain-derived molecules that enhance the growth of neurons and improve their potential for survival. 

Neurotrophic factors can act on the visual pathway in multiple ways. Ciliary neurotrophic factor (CNTF), for example, may:

• Prevent the death of retinal ganglion cells 
• Increase axon regeneration along the optic nerve 
• Strengthen support between dying retinal ganglion cells and surrounding cells in the retina and brain

Recognizing that the eye-brain connection is critical to understanding glaucoma has already led to significant advances in research. Further exploration and understanding of this relationship makes a host of potential new treatments possible.

*Goldberg, J. L. (2017, Oct. 29).Glaucoma and the Brain. Glaucoma Research Foundation. https://www.glaucoma.org/glaucoma/glaucoma-and-the-brain.php