What is glaucoma
Glaucoma is a collective term for a group of neurodegenerative eye diseases that cause irreversible blindness. It’s the second leading cause of blindness worldwide, with about 3 million Americans alone diagnosed with this condition.
The risk of developing glaucoma increases each year of age. Its most commonly found in older adults over the age of 60.
Those of African American, Asian, or Hispanic descent have a higher chance of developing glaucoma than those who are Caucasian .
Glaucoma often goes undetected in the early stages of development as some people don't realize their vision is changing. As many as 50% of patients aren’t diagnosed until their condition is severe. To help with early detection, it’s important to undergo routine exams at the eye doctor.
Having other health conditions
Diabetes, high blood pressure, heart disease, and sickle cell anemia may increase the risk of glaucoma.
If glaucoma runs in your family, the chances of you having it are higher.
Symptoms glaucoma patients experience are: vision blind spots in the peripheral (side) or central vision, eye redness, eye pain, headaches, seeing rainbow-colored circles around bright lights, being sensitive to light, and nausea or vomiting.
The different types of glaucoma
There are generally four different types of glaucoma: primary open angle glaucoma, angle closure glaucoma, normal tension glaucoma, and secondary glaucoma.
Primary open angle glaucoma
Primary open angle glaucoma is the most common type. Its caused by damage to the optic nerve from increased intraocular pressure, or pressure inside the eye. Normal eye pressure is between 10 to 21 mm Hg in healthy adults, anything above that can damage the eyes.
This increased eye pressure could be caused by overproduction of fluid within the eye or by reduced outflow of fluid from the eye . In either scenario, the fluid drain becomes blocked, which is the cause of increased eye pressure.
This type progresses slowly, with symptoms taking years to show up. The most common symptom reported with this specific type of glaucoma is worsened peripheral (side) vision.
Angle closure glaucoma
Angle closure glaucoma is similar to primary open angle glaucoma because it’s caused by high eye pressure from a closed off fluid drain. This drain is located in the corneal angle (at the edge of the cornea in the eye), which is where the name “angle closure” originates.
When the drain becomes closed off or narrowed, fluid gets stuck in the eye which raises eye pressure significantly. Unlike the primary kind that progresses slowly, this condition has a rapid onset. Severe eye pain, headaches, and blurred vision are commonly experienced. Unfortunately, though it has a quick onset it’s still a long-term condition, even with treatment.
Normal tension glaucoma
Normal tension glaucoma, unlike the previous two types of glaucoma, is not caused by increased eye pressure. Damage to the optic nerve, which can be caused by a variety of things, is responsible for this type of glaucoma.
Secondary glaucoma is the development of glaucoma from another condition. It’s characterized by an increase in eye pressure which damages the optic nerve, but the cause of the increased eye pressure is the result of another condition, most commonly cataracts or prolonged steroid use.
When the doctor conducts an eye exam testing for glaucoma, they will look at several factors to determine the presence of glaucoma.
- Measuring intraocular pressure
- testing for optic nerve damage with a dilated eye examination and imaging tests
- Checking for areas of vision loss (visual field test)
- Measuring corneal thickness
- Inspecting the drainage angle (gonioscopy) 
Causes of glaucoma
There is no singular cause but several factors that can contribute to developing glaucoma.
Death of retinal ganglion cells
Retinal ganglion cells (RGCs) areneurons near the inner surface of the retina of the eye. They receives visual information from photoreceptors and pass the images on to the brain to create vision. Death of these cells is what causes glaucoma-induced vision loss. The more cells that die, the worse vision loss becomes. Since they're nerves, once they die they're unable to be regenerated and vision loss is permanent.
Oxidative stress is an imbalance between free radicals and antioxidants in the body. Free radicals are molecules with an uneven number of electrons, making it unstable as the ratio of positively charged protons and negatively charged electrons becomes unbalanced. This instability allows them to react easily with other molecules, and this reaction is called oxidation.
Oxidative stress plays a role in many diseases, including neurodegeneration. A molecule called reactive oxygen species (ROS), a free radical that contains oxygen, is involved in retinal ganglion cell death, which causes vision loss.
Chronic oxidative stress may damage the trabecular meshwork function. The trabecular meshwork is the spongy tissue by the cornea where the aqueous humor fluid flows out of.
Exposure to oxidative stress is unavoidable, so the trabecular meshwork has a inherent defense mechanism against ROS molecules. Studies show we lose 0.58% of the cells here each year (the study measured birth to 81 years old) . But in patients with glaucoma, this percentage can be much higher.
The mitochondria are organelles in the cells that create ATP (energy) through oxidative phosphorylation and regulate cell death, or apoptosis.
Mitochondrial dysfunction is increasingly recognized as playing a role in neurodegenerative disorders, including Alzheimer and Parkinson disease and glaucoma . It may be the cause of the death of retinal cells, as “the specific loss of retinal ganglion cells is a common feature of mitochondrial diseases… the retinal ganglion cell, due to peculiar structural and energetic constraints, appears acutely susceptible to mitochondrial dysfunction” .
Mitochondrial function is thought to decline with age, which may support why the prevalence of glaucoma increases with each year of age.
Mitochondrial dysfunction can be caused by multiple factors: genetic abnormalities in either nuclear DNA or mitochondrial DNA (the specific set of DNA you receive from your mother), environmental stressors (toxin exposure, nutrient deficiencies, electron leakage in the electron transport chain), or light-induced oxidative stress.
Nutrient deficiencies in mitochondrial disorders are typically in vitamins B (especially vitamin B3) and D, iron, and calcium . Also, intake of fiber, protein, sugar, and saturated fat may influence mitochondrial health as well.
Light-induced oxidative stress refers to excess blue light exposure, which is now considered to be a risk factor for the development of certain diseases as it contributes greatly to oxidative stress. With so much of our time spent indoors, our exposure to natural light is minimized and exposure to artificial light and blue light from screens is increased. This is linked to retinal injuries and progression of degenerative retinal diseases, like glaucoma.
Although there is no way to cure glaucoma or reverse vision loss, there are several treatment options that can prevent or slow its progression and improve eye health.
Eye drops and medication
The most common form of treatment is prescription eye drops that lower ocular pressure. It does this by either improving eye drainage or by decreasing the amount of fluid produced in the first place. Prostaglandins and miotic agents are typically used to improve drainage; beta blockers, alpha-adrenergic agonists, and carbonic anhydrase inhibitors are used to reduce the production of eye fluid.
If eye drops aren’t helping, the next step can be taking medication, usually a carbonic anhydrase inhibitor.
Carbonic anhydrase is an enzyme in the kidneys that converts carbonic acid into water and carbon dioxide and later vice versa, converting water and carbon dioxide back into carbonic acid. It works as a diuretic, decreasing both blood pressure and eye pressure. For the eyes, it reduces the production of aqueous humor, the clear fluid that nourishes the eye and keeps it inflated. It can cause adverse effects, but can be helpful in decreasing the damage caused by high eye pressure.
Laser therapy and surgery
Laser trabeculoplasty can be helpful in helping open-angle glaucoma. A doctor uses a laser beam to open up the clogged drainage channels in the trabecular meshwork.
There are several different surgery options available that improve eye drainage. Filtering surgery is when the surgeon creates an opening in the sclera, the white part of the eye, and removes part of the trabecular meshwork. Another option is drainage tube surgery, where the surgeon inserts a tube shunt into the eye to drain excess fluid .
Since damage caused by glaucoma is irreversible, focusing on prevention is key. The nutrients below may help glaucoma by increasing aqueous flow and lowering eye pressure, decreasing oxidative stress, preventing optic nerve damage, which prevents retinal ganglia cell death, increase blood flow, and supporting mitochondrial health .
Since oxidative stress is thought to contribute to glaucoma progression, antioxidants are important to minimize the negative effects oxidative stress causes.
Vitamin C can protect the optic nerve from oxidative stress by absorbing the free radicals caused by oxidation, thus decreasing cellular damage from the free radicals.
Vitamin C also regenerates vitamin E and glutathione. Vitamin E, another antioxidant, works to absorb free radicals found in the eye membrane. Vitamin C decreases the amount of vitamin E radicals that form when vitamin E is absorbing the oxygen radicals, boosting the effects of vitamin E. Vitamin C also regenerates glutathione, a substance involved in tissue building and immune system function.
In glaucoma patients, the ascorbic acid, another term for vitamin C, concentration in the aqueous humor was 45% lower than the control group .
Ginkgo biloba is a plant compound that’s been a part of traditional Chinese medicine for hundreds of years. It was used to treat brain, respiratory, and circulatory conditions.
In recent studies, it has been shown to improve blood flow by relaxing blood vessels and has neuroprotective effects, protecting neurons from damage through its antioxidant properties . It’s potent antioxidant effects come from compounds known as flavonoids, which are plant compounds that provide a variety of phytonutrients and antioxidants.
In a randomized trial testing the effect of Ginkgo on ocular blood flow, researchers found two days of Ginkgo supplementation increased blood flow in the ophthalmic artery, which delivers blood to the orbital cavity . However, this study was small and larger studies are required to back up these findings.
Resveratrol is another plant polyphenol with potent antioxidant, anti-inflammatory, neuroprotective, and anti-aging effects . Its unique in that it may also improve mitochondrial dysfunction.
In a literature review, a study found resveratrol decreases inflammatory markers in the trabecular meshwork cells and another study found it slowed the apoptotic, or cell death, process .
Magnesium may help improve glaucoma as it improves ocular blood flow. It can relax blood vessels, decreasing blood pressure and increasing blood flow. A compound called endothelin-1, a vaso-constrictor that may be the cause of abnormal eye blood flow in glaucoma patients, is down-regulated by magnesium .
In a study testing the effects of magnesium on glaucoma, the magnesium-treated patients had significant reduction in mean IOP (intraocular pressure) from their initial values . But it’s important to note some researchers believe no difference would be measured if the patient does not have a pre-existing magnesium deficiency.
Correcting nutrient deficiencies
As emerging evidence continues to implicate nutritional deficiencies in disease causation, it’s important to ensure you’re eating a healthy diet with adequate amounts both macronutrients and micronutrients.
Fiber, protein, and fat compounds like omega-3s and omega-6s, are important to get enough of. Low fiber, protein, and fatty acid intake is linked to mitochondrial dysfunction and glaucoma. Most Americans don’t get the recommended amount of fiber or omega fats each day, which may contribute to the large amount of people who develop glaucoma and other neurodegenerative diseases.
Vitamin and mineral deficiencies can arguably be found to worsen almost every disease or condition out there. In glaucoma, getting enough vitamin D, B, calcium, magnesium, iron, and antioxidants may help prevent or treat it.
Given the large variety of nutrients to cover, it can be hard to intake adequate amounts of every vitamin and mineral. A high-quality multivitamin supplement can benefit your health in the short and long term. Rootine formulates personalized vitamin supplements by analyzing 100+ health data points across your DNA, blood, and lifestyle to create a precision multivitamin tailored for you. This is key for disease prevention and overall improved health.
Getting outside more often, especially in the morning time to reset your circadian rhythm, and minimizing blue light exposure can decrease oxidative stress from blue light. Since blue light is unavoidable with school, work, and modern life in general, blue light blocking glasses can be helpful to wear, especially if you’re on screens at night. This can minimize light-induced oxidative stress that contributes to glaucoma.
1. EyeDocs Family Eye Care. (2022, February 22). 4 types of glaucoma. EyeDocs Family Eye Care. Retrieved June 7, 2022, from https://eyedocsbrookville.com/4-types-of-glaucoma/
2. Mayo Clinic Staff. (2020, October 23). Glaucoma. Mayo Clinic. Retrieved June 7, 2022, from https://www.mayoclinic.org/diseases-conditions/glaucoma/diagnosis-treatment/drc-20372846
3. Hornick , L. (n.d.). Nutritional supplements for glaucoma. Modern Optometry. Retrieved June 7, 2022, from https://modernod.com/articles/2021-nov-dec/nutritional-supplements-for-glaucoma?c4src=article%3Ainfinite-scroll
4. Ferreira, S., Reides, C., Lerner, F., & Llesuy, S. (n.d.). Evidence of oxidative stress damage in glaucoma. IntechOpen. Retrieved June 7, 2022, from https://www.intechopen.com/chapters/18949
5. Gonzalez, A. (n.d.). 8 risk factors for glaucoma. 8 Risk Factors for Glaucoma. Retrieved June 7, 2022, from https://www.communitymedical.org/about-us/news/8-risk-factors-for-glaucoma
6. Magnesium therapy and primary open-angle glaucoma. EuroTimes. (2016, August 31). Retrieved June 7, 2022, from https://www.eurotimes.org/magnesium-therapy-and-primary-open-angle-glaucoma/
7. Freeman, E. (n.d.). Ginkgo biloba and ocular blood flow in primary open-angle glaucoma - full text view. Full Text View - ClinicalTrials.gov. Retrieved June 7, 2022, from https://clinicaltrials.gov/ct2/show/NCT02376114
8. Abu-Amero KK, Kondkar AA, Chalam KV. Resveratrol and ophthalmic diseases. Nutrients. 2016;8(4):200.
9. Kong, G., Bergen, N., & Trounce, I. (n.d.). Mitochondrial dysfunction and glaucoma. Journal of glaucoma. Retrieved June 7, 2022, from https://pubmed.ncbi.nlm.nih.gov/19225343/
10. Lee, S., Bergen , N., & Kong, G. (n.d.). Mitochondrial dysfunction in glaucoma and emerging bioenergetic therapies. Experimental eye research. Retrieved June 7, 2022, from https://pubmed.ncbi.nlm.nih.gov/20691180/
11. Zweers, H., Janssen, M., & Leij, S. (n.d.). Wiley Online Library - American Society for Parenteral and enteral ...Aspen Journals . Retrieved June 7, 2022, from https://aspenjournals.onlinelibrary.wiley.com/