This article is for informational purposes only and does not diagnose any conditions
The best ways to protect the optic nerve are to ensure adequate blood flow to the optic nerve cells and to limit exposure to harmful oxidative stress from free radicals.
The optic nerve, also called the second cranial nerve, is a bundle of over 1 million nerve fibers that provides the link between the eye and the brain. When we see something, light rays are transmitted to the retina, a structure in the back of the eye. The retina then takes light energy and converts it to electrical energy and transmits nerve impulses via the optic nerve to the brain, where a visual image is formed.
There are several eye disorders that can cause strain or damage to occur to the optic nerve, including glaucoma, optic neuritis, optic nerve atrophy and optic nerve head drusen.
Glaucoma is the most well-known eye disorder that causes optic nerve damage. Glaucoma often occurs when there is an increase to the pressure inside the eye (intraocular pressure). As pressure inside the eye rises, over time, it damages the optic nerve fibers leading to impaired vision. It is not fully understood if the optic nerve damage occurs because of the mechanical compression of the nerve fibers from the increased pressure, or if the pressure restricts necessary blood flow to the optic nerve. As nerve fibers become damaged, they are unable to transmit light from the retina to the brain, meaning that blind spots may begin to occur in the field of vision. Glaucoma damage usually initially starts with loss of peripheral vision.
Optic neuritis is an inflammation of the protective sheath (myelin) that surrounds the optic nerve which can occur when someone has a severe infection, or may be caused by immune system disorders, like multiple sclerosis. Symptoms of optic neuritis can include blurred or distorted vision or blind spots, and sometimes pain during eye movement.
Optic nerve atrophy describes a degeneration or damage of the optic nerve. Some causes of optic nerve degeneration may be due to poor oxygen or blood supply to the optic nerve, which can be the result of a traumatic injury to the eye, an infection, exposure to toxins, a stroke, or a tumor.
Optic nerve head drusen are small globular deposits of protein and calcium salts that build up at the front of the optic nerve (the head) over time. These deposits are thought to be a by-product of abnormal flow of cellular material in the optic nerve cells. Some people have no symptoms from these drusen, while others may notice a decline in vision, or a “dimming” of their vision.
How can I protect my optic nerve?
The main causes for degenerative damage to the optic nerve are thought to be due to impairment of good blood flow to deliver nutrients and remove waste products, and oxidative stress that causes cell damage and cell death to many eye tissues and structures. There are ways to counteract this:
1. Maintaining optimal blood flow to the optic nerve. Optimal blood flow is vital to maintain a healthy optic nerve. Blood carries important nutrients and oxygen which help nourish the optic nerve.
2. Maintaining a healthy eye pressure (intraocular pressure). The pressure in the eye (also known as intraocular pressure) is very important to help support optic nerve health. A healthy eye pressure leads to a healthy optic nerve.
3. Supporting mitochondrial health. Mitochondria are the powerhouses of the human cells. They take in nutrients from blood and create energy rich molecules for the cell. Healthy mitochondria are essential for a healthy optic nerve.
4. Limiting exposure to oxidation with antioxidants. Oxidation can impact retinal cells, which are critical for vision and feed impulses to the optic nerve. Limiting exposure to oxidation is important for optic nerve health.
Antioxidants play a vital role in our bodies is to help prevent cellular damage from oxidative stress. They help to deactivate harmful free radicals, which are atoms of oxygen that can damage cells within the body (oxidative damage and oxidative stress). Free radicals are unstable atoms that cause damage to healthy cells when they move through the body in search of an electron to make them more stable. Research has shown that the damage caused by free radicals can lead to increased risk of cancer, heart disease and eye disease. Oxidative stress can also directly contribute to cell death (retinal ganglion cells –critical neurons for vision because these cells all feed impulses directly to the optic nerve) in the inner retinal layers, which can be further compounded by elevated pressure inside the eye in people with glaucoma.
What are some nutrients that have been shown to be beneficial to optic nerve health?
Bilberry –Bilberry fruit and its extract are powerhouses of good nutrition. Currently, bilberry fruit is used in jams and as a baking ingredient, but the concentrated extract is used in supplements to help manage circulation issues, disorders of the retina, glaucoma, and cataracts. The pharmacologically active ingredients of the bilberry are a group of compounds called anthocyanins (chemical compounds that give them their deep purple color), which have powerful antioxidant and anti-inflammatory action.
Studies have shown the neuroprotective effects of bilberry supplementation and its ability to suppress death of retinal ganglion cells and it also increased the levels of a specific protein that show that it has an underling neuroprotective effect after optic nerve injury or retinal injury or crush from increased pressure inside the eye. 
Blackcurrants - Blackcurrants are packed with antioxidant, antibacterial, and antiviral properties. Research has shown that anthocyanin-rich blackcurrants may have to ability to inhibit multiple biological pathways in the retina to protect visual function.  The increased levels of antioxidant defense, suppress the chemical reactions that cause inflammation in its early stages, and reduce the occurrence of retinal cell death, having a tissue-protecting effect. 
Study results have shown that people who consumed 50mg blackcurrants daily were found to have improved blood flow in their eye, a decrease in elevated intraocular pressure (pressure inside the eye), and reduced visual field loss compared to those that did not receive any blackcurrants. [2, 3, 4] These little berries have high levels of potassium, calcium, magnesium and iron and contain γ-linolenic acid, an essential polyunsaturated fatty acid.
Quercetin - Quercetin is a type of flavanol, known for promoting healthy blood vessel function. Studies have shown that damage to the optic nerve may be linked to unstable perfusion of the optic nerve head and retina, meaning that there are large fluctuations in blood flow and pressure, another source of oxidative stress.  Quercetin can be found in leafy vegetables, broccoli, red onions, peppers, apples, grapes, black tea, green tea, red wine, and some fruit juices. Research studies have also reported quercetin to have excellent antioxidative, anti-inflammatory, and anti-proliferative capabilities. Studies specific to retinal and macular health have shown that quercetin can also be protective of retinal pigment epithelial cells. Additionally, studies have shown that quercetin could significantly improve vision and functional recovery of the optic pathway (link from retina to brain) by its protective effects on the protective sheath (myelin) that surrounds the optic nerve and regulation of central nervous system cells (glial cells). 
Grape Seed - Grape seed extract is a potent antioxidant, so it helps prevent damage due to ongoing oxidative stress. In laboratory studies, grape seed extract has been shown to protect neurons and nerve cells, specifically retinal ganglion cells, against the damaging effects and cell death caused by oxidative stress.  Grape seed extract also promotes normal vascular function, meaning good blood flow and health of blood vessels throughout the body.
Coenzyme Q10 (CoQ10) - Coenzyme Q10 is an antioxidant that is naturally produced in the body, but this production declines as we age. The cells in the body use CoQ10 for growth and maintenance it has been studied as a potential protective agent for the retinal cells and neurons. A recent review of research related to CoQ10 concluded that there is an increasing body of evidence supporting the potential beneficial effect of CoQ10 in protecting neuroretinal cells from oxidative damage. 
Niacinamide (Niacin) – Also known as one of the two forms of vitamin B3 (the other is nicotinic acid), niacinamide has been shown to have a protective effect on nerve cells in the retina that can become less active or functional as we age. In a laboratory study in animals, researchers found that administering niacinamide boosted the metabolic reliability (normal cell activity and functioning) of aging retinal ganglion cells, keeping them healthier for longer. This is an important finding because decreased levels of niacinamide were found to reduce the reliability of neurons’ energy metabolism, like in the optic nerve, especially under additional stress such as increased intraocular pressure as in eyes with glaucoma. 
Saffron – Saffron is a powerful antioxidant to help prevent damage from oxidative stress, and there is also scientific evidence that it can lower elevated pressure in the eye. In a clinical study, people with primary open angle glaucoma took daily oral supplements of saffron in addition to their prescribed eye drops (timolol 0.5% twice daily and dorzolamide 2% three times daily). After only three weeks, participants taking saffron experienced significant reductions in their intraocular pressure compared to those that were taking a placebo.  Additionally, laboratory animal studies have shown that saffron may protect photoreceptors from retinal stress, maintaining good structure and function of retinal cells.  A recent laboratory study also concluded that Crocin, one of the major active ingredients in saffron, effectively suppresses abnormal activity of the central nervous system immune cells (microglial activation), which has been shown to lead to death of retinal ganglion cells and progression of glaucoma. 
Sometimes getting enough of some important nutrients from our diets alone can be challenging, so many people consider adding a supplement to their daily routine to help to reach the recommended amount to meet their specific needs. It is important to carefully read product labels and confirm that the supplement is of the highest quality, from a reputable company, and contains appropriate nutrient amounts and no unwanted ingredients such as dyes or fillers.
When considering a nutritional supplement, it is always important to check with your physician or health care professional.
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 Hiroshi Ohguru, Ikuyo Ohguro, Saeko Yagi Effects of Blackcurrant Anthocyanins on Intraocular Pressure in Healthy Volunteers and Patients with Glaucoma. JOURNAL OF OCULAR PHARMACOLOGY AND THERAPEUTICS 2013, Vol 29 No.1:61-67
 Ikuyo Ohguroll, Hiroshi Ohgurol, Mitsuru Nakazawa Effects of anthocyanins in black currant on retinal blood flow circulation of patients with normal tension glaucoma. A pilot study. HIROSAKI MEDICAL ]OURNAL. 59: 23-32. 2007. https://hirosaki.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3602&item_no=1&attribute_id=20&file_no=1
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