Glaucoma is the result of increased intraocular eye pressure (IOP) and damage the optic nerve, the nerve that carries visual information from the eye to the brain. In fact, recent research has shown that this complex connection between the eye and the brain is an important key to glaucoma, which is why many researchers are now viewing glaucoma as a neurodegenerative disease. “Glaucoma shares a number of features with degenerative brain diseases such as Alzheimer’s, Parkinson’s, and Lou Gehrig’s disease,” writes Jeffrey L. Goldberg, MD, PhD, Professor and Chair of Ophthalmology at the Byers Eye Institute at Stanford University School of Medicine. In each of these neurodegenerative diseases, age and family history are major risk factors and specific areas of the brain are damaged over time. With glaucoma, this “specific area” is the optic nerve, as we mentioned above.
Yes, the Optic Nerve is Part of the Brain
During early development, a small part of the brain puffs out and becomes the optic nerve, which is made of ganglionic cells (nerve cells) and over one million nerve fibers. The optic nerve is also referred to as the second cranial nerve or cranial nerve II. The job of the optic nerve is to transfer visual information from the eye to the brain via electrical impulses.
Inside the eye, ganglion cells collect visual information and pass it down their extensions, called axons, through the optic nerve and to the visual receptors of the brain. These ganglion cells are one of the types of cells initially damaged by glaucoma.
“Researchers have observed that specific areas of injured optic nerve axons and retinal ganglion cell loss match the peripheral vision damage from glaucoma,” writes Dr. Goldberg. “Because the retinal ganglion cell axon stretches from the retina through the optic nerve to the brain, its surrounding cells also become damaged by glaucoma.”
This all results in several things: 1) Other cells within the retina, such as the amacrine cells, degenerate and rewire their connections. 2) There are even changes within the brain. Specifically, changes within the lateral geniculate nucleus (the main brain target of optic nerve axons) and the visual cortex. Because of this, many researchers are now looking at glaucoma differently. Instead of directing treatment at lowering IOP, there may also be opportunities to develop treatment directed at the retina and the brain. One such promising treatment that promotes nerve health – neurotrophic factors – could help along multiple place in the visual pathway.
“For example, neurotrophic factors such as ciliary neurotrophic factor (CNTF) may keep retinal ganglion cells from dying, a process called neuroprotection; they may increase axon regrowth down the optic nerve, called regeneration; and they may improve the support between the dying retinal ganglion cells and their surrounding cells in the retina and brain, called neuroenhancement,” says Dr. Goldberg.
Glaucoma Treatment in Annapolis, Maryland
The Anne Arundel Eye Center, led by board certified ophthalmologist Dr. Samuel Boles, is a regional leader in the diagnosis and treatment of glaucoma and cataracts. Staffed by caring and knowledgeable professionals, AAEC’s state-of-the-art treatment center is dedicated to making the best eye care accessible to everyone.
As part of our comprehensive medical evaluation, we will be happy to provide you with a referral to an optometrist or ophthalmologist who can fit you for glasses or contacts or provide Lasik services.
If you have any questions, please contact Dr. Samuel Boles, Dr. Nicole Kershner Regis, Dr. Kathryn Turner, and the eye care specialists here at AAEC by calling 410-224-2010. AAEC is staffed by caring and knowledgeable professionals who will help guide you on your healing journey.