Glaucoma is a group of ocular conditions characterized by optic nerve changes, which can lead to vision challenges. Glaucoma affects three million Americans and is a significant cause of vision impairment in the United States. However, many people with glaucoma may not be aware they have it. While there is no known cure for glaucoma, routine screening and management strategies can help maintain vision and eye health. This article will discuss a functional approach to supporting eye health in the context of glaucoma. (1)
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What is Glaucoma?
Glaucoma is a group of conditions that can affect vision by impacting the optic nerve. In many cases, fluid builds up in the front part of the eye, which may increase intraocular pressure (IOP) and affect the nerve. Most people with glaucoma have it in both eyes, but one eye may be more affected than the other. (2, 4)
There are many types of glaucoma, classified as either primary (unrelated to another medical condition) or secondary (related to an underlying medical condition). Primary glaucoma is more common than secondary glaucoma. (3)
The main forms of primary glaucoma include:
Open-Angle Glaucoma
Open-angle is the most common type of glaucoma in the United States, affecting many Americans with glaucoma. Open-angle glaucoma occurs when fluid drains too slowly through the eyes' drainage canals, despite normal anatomy. Over time, increased IOP may affect the optic nerve and vision. (3, 4)
Closed-Angle Glaucoma
Also called angle-closure glaucoma, this is a form of glaucoma that occurs when the angle between the iris and cornea blocks fluid from draining out of the front portion of the eye. Fluid in the eye can quickly build and cause an increase in IOP. (3, 4)
Normal-Tension Glaucoma
Normal-tension glaucoma is a subtype of open-angle glaucoma that occurs with normal eye pressure. (4)
Congenital Glaucoma
Congenital glaucoma affects a small number of babies born in the United States. This type of glaucoma occurs when the eyes' drainage canals don't form properly during fetal development. (3, 4)
Glaucoma Signs & Symptoms
Open-angle glaucoma doesn't present with warning signs or symptoms in its early stages, making it a "silent thief of sight." As the condition progresses, peripheral painless vision changes may occur. Uncontrolled forms of open-angle glaucoma can result in central vision changes. (5, 6)
Closed-angle glaucoma episodes may present with severe eye and forehead discomfort, eye redness, vision changes, visual halos, headache, nausea, and vomiting. Individuals experiencing these symptoms should seek immediate medical attention to address potential vision changes. (5)
Children born with congenital glaucoma usually present with immediate signs and symptoms, including cloudy eyes, light sensitivity, increased tear production, and larger-than-normal eyes (3).
What Causes Glaucoma?
The exact cause of glaucoma is not fully understood, but there is a clear correlation between IOP and the development of glaucoma. In a healthy eye, eye fluids (called aqueous humor) flow through the pupil to the front of the eye and then drain through canals between the iris and cornea. With glaucoma, drainage resistance may develop in these canals, and excess fluid that builds up can put pressure on the optic nerve over time.
Changes in collagen metabolism and resulting structural changes in the eye can affect aqueous humor and blood flow through and to the eye. These changes can result in elevated IOP and vision changes. (7)
Hypothyroidism, a prevalent endocrine condition characterized by low thyroid hormones, may increase the risk of developing primary open-angle glaucoma. It is suggested that the increased IOP seen in hypothyroidism is related to mucopolysaccharide deposition in the eyes, affecting aqueous humor outflow. (8)
Other important factors that may increase the risk of developing glaucoma include (4, 6):
- Age over 55
- Race and ethnicity: people of Black, Asian, and Hispanic heritage may have a higher likelihood of developing glaucoma
- Family history of glaucoma
- Medical conditions: diabetes, hypertension, sickle cell anemia, migraines
- Chronic use of corticosteroids
- Extreme nearsightedness (increased risk of open-angle glaucoma) or farsightedness (increased risk of closed-angle glaucoma)
- History of eye injury or surgery
Functional Medicine Labs to Test for Root Cause of Glaucoma
Evaluation for glaucoma requires a comprehensive dilated eye examination that includes measuring intraocular pressure (tonometry), visual field testing, measuring corneal thickness (pachymetry), and inspecting the drainage angle (gonioscopy). A glaucoma diagnosis is made based on characteristic clinical and physical exam findings. (2)
Functional medicine labs can help practitioners personalize options for their patients. Below are some of the most common labs considered for individuals with glaucoma.
Blood Sugar
Fasting blood glucose, insulin, and hemoglobin A1c (HbA1c) can be ordered to comprehensively assess blood sugar regulation. Elevated levels are associated with hyperglycemia, insulin resistance, and diabetes mellitus.
Thyroid Panel
A thyroid panel, including TSH, free T4, and free T3, can help assess thyroid function. Hypothyroidism is associated with elevated TSH levels and low free T4 and/or free T3 levels.
Micronutrient Assessment
A comprehensive micronutrient test can identify levels of vitamins and minerals important in maintaining eye health. This test's results can help personalize a nutritional and supplemental plan based on the individual's nutritional status.
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Conventional Approaches for Glaucoma
Conventional approaches primarily involve medications to manage IOP to help maintain vision. Typical pharmacologic agents for managing glaucoma include beta-blockers, alpha-agonists, and miotic agents. Occasionally, laser therapy or surgery is performed to improve aqueous outflow. (8)
Functional Medicine Considerations for Glaucoma
Functional medicine practitioners can suggest a personalized plan for glaucoma that includes dietary and supplemental considerations based on an extensive intake and lab results.
Medical conditions that may increase the risk of glaucoma need to be managed appropriately. This article will not discuss these protocols, but they can be found in the Rupa Health Magazine.
Diet and Nutrition Considerations for Glaucoma
Healthy dietary choices provide the body with nutrients that support eye health, help protect against oxidative stress, and support cardiovascular health. Fruits, vegetables, nuts, and seeds are good sources of vitamins A, C, E, lutein, and zeaxanthin, which are known to support eye health. Research suggests that consuming at least three servings of fruits and vegetables daily may help support eye health. In particular, green leafy vegetables appear to be particularly beneficial in supporting eye health.
MIND Diet
The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet is associated with a lower incidence of open-angle glaucoma and can be considered to support eye health. The MIND diet guidelines are as follows:
Foods to Include in the Diet
- At least three servings of whole grains daily
- At least one serving of non-green leafy vegetables daily
- At least six servings of green leafy vegetables weekly
- At least five servings of nuts weekly
- Include beans in at least four meals weekly
- At least two servings of berries weekly
- Include poultry in at least two meals weekly
- Include fish in at least one meal weekly
- Use olive oil as the primary source of fat
Foods to Limit in the Diet
- Less than five servings of pastries and sweets weekly
- Less than four servings of red meat (i.e., beef, pork, lamb) weekly
- Less than one serving of cheese and fried foods weekly
- Less than one tablespoon of butter/margarine daily
Decrease Caffeine
Ingestion of a single serving (200-360 mL) of caffeinated coffee may cause transient elevations in IOP. Additionally, research suggests that drinking large amounts of caffeine daily (480 mg or four cups of coffee) may increase the risk of glaucoma in those with a genetic predisposition to elevated IOP. Based on these findings, it may be helpful to consider a trial of caffeine avoidance for 4-6 weeks to observe the effects on IOP. Consider replacing caffeinated beverages with decaffeinated tea; according to one study, individuals who drink at least one cup of hot tea daily may support their eye health.
Supplement Considerations for Glaucoma
Below are some nutritional and herbal supplements to consider incorporating into a nonpharmacologic plan for supporting eye health in the context of glaucoma.
Ginkgo
Ginkgo (Ginkgo biloba) is rich in terpenoids and flavonoids, which are responsible for its many health-supporting properties, including antioxidant and vasodilator effects. Its ability to support blood flow to the eyes makes it a valuable herb in supporting eye health. (9-11)
Dose: 40 mg three times daily
Glutathione
Glutathione is often called the body's "master antioxidant" because it helps manage oxidative stress. Depletion of glutathione is associated with neurodegeneration and the development of eye conditions (12, 13).
Dose: compounded eye drops 1 mg/mL; apply two drops in each eye once daily
Fruit Anthocyanins
Anthocyanins are a type of plant flavonoid responsible for plants' deep red, purple, and blue pigments. Flavonoid-rich extracts can help manage free radical damage and support blood vessel and collagen integrity. Research also shows that anthocyanins can support blood pressure and neurological health. The Fruit Anthocyanins concentrate formulated by Dr. William Mitchell is a popular supplement among functional practitioners for supporting eye health. (14)
Dose: 1 tbsp once daily
Magnesium
Magnesium levels have been studied in individuals with glaucoma and are associated with antioxidant imbalances and inflammation. Magnesium supplementation can support blood pressure and has been studied for its potential to support visual field health in glaucoma. (15)
Dose to bowel tolerance at three times daily dosing.
Vitamin C
Vitamin C plays a role in maintaining a healthy collagen network and is a potent antioxidant. It has been studied for its potential to support IOP.
Dose to bowel tolerance at three times daily dosing.
When to Retest Labs
Changes in IOP may be observed as early as four weeks after initiating a glaucoma support plan like the one described above. If no changes to symptoms or IOP are observed at this time, it may be helpful to revise the plan. Long-term adherence to a glaucoma support plan is often required to maintain eye health.
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Summary
Glaucoma is a condition that can affect the eyes and is typically related to increased intraocular pressure. It can potentially cause changes in vision. Open-angle glaucoma is the most common type and usually doesn't present with any symptoms until optic nerve changes have occurred. A healthy diet, the management of chronic cardiovascular conditions, and regular eye exams are important in supporting eye health. An integrative approach may include pharmacologic medications and natural supplements to support intraocular pressure and optic nerve health.
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