What are the differences between macular degeneration and glaucoma?

What are the differences between macular degeneration and glaucoma? Both conditions can cause vision loss, both affect millions of people around the world, and both often afflict people who are well into adulthood.

Yet macular degeneration and glaucoma are far from identical. Namely, macular degeneration involves the deterioration of the center of the retina, while glaucoma inflicts damage to the optic nerve.

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What is macular degeneration?

Macular degeneration harms the center portion of the retina — the inside back layer of the eye that captures images we see and sends them to the brain via the optic nerve. The central part of the retina, called the macula, is responsible for our central vision. It controls our ability to read, recognize faces and colors, drive a car, and see objects in fine detail.

In 2020, an estimated 196 million people worldwide are living with macular degeneration. Advanced age-related macular degeneration (AMD) is the world’s leading cause of irreversible blindness and visual impairment, according to the BrightFocus Foundation, whose funding backs research in macular degeneration and glaucoma.

People 55 and older are at the highest risk of developing AMD. Aside from age, risk factors for macular degeneration include:

• Family history of macular degeneration.

• Race: White people are more likely to have macular degeneration than other racial groups.

• Smoking: Cigarette smoking doubles the risk of developing macular degeneration.

The cause of macular degeneration remains unclear, and there’s no known cure. Macular degeneration treatment options exist but they benefit only a small number of patients. However, new treatments, such as stem cell therapy, are in the works.

Macular degeneration exists in two forms:

• Dry macular degeneration, which accounts for 90% of diagnosed cases.

• Wet macular degeneration, which accounts for 10% of diagnosed cases but results in 90% of legal blindness.

Symptoms of both types of macular degeneration might not appear during the early stages of the disease. Signs include shadowy areas in your central vision, unusually fuzzy or distorted vision, wavy or distorted words when reading, difficulty seeing details in poor lighting conditions, and sensitivity to glare.

What is glaucoma?

Glaucoma causes damage to the optic nerve, which carries information from your eyes to your brain.

In 2020, an estimated 111 million people around the world have the disease. Globally, it’s the second leading cause of vision loss, according to the American Academy of Ophthalmology.

This disease can’t be cured, and any vision lost to the disorder can’t be restored. Higher-than-normal pressure in the eye usually causes the disease, but elevated intraocular pressure (IOP) doesn’t always result in glaucoma, and not all cases of the disease are the result of high IOP.

Groups at higher risk of developing glaucoma include:

• People over 60

• African Americans

• People with a family history of the disease

• Diabetics

• People with severe nearsightedness

Treatments for the disease include medicated eye drops, microsurgery, laser treatments and other procedures.

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Glaucoma comes in several forms. Two of the most common are:

• Open-angle: With this type, the drainage angle in your eye (located where the iris meets the cornea), which is where fluid that's produced inside the eye exits the eye, is as open as it should be, but the mesh-like filtering structure within it (trabecular meshwork) becomes clogged over time. This causes pressure inside the eye (intraocular pressure, or IOP) to increase, and this high eye pressure eventually damages the optic nerve and causes vision loss.

• Angle-closure: This type, also called narrow-angle glaucoma, occurs when the drainage angle narrows and becomes blocked, which leads to a sudden increase in IOP. Due to its rapid onset, angle-closure glaucoma requires immediate medical attention.

Open-angle glaucoma has no symptoms until significant vision loss has occurred. However, angle-closure glaucoma has several symptoms, including:

• Hazy or blurred vision

• The appearance of rainbow-colored circles around bright lights

• Severe eye pain and headache

• Nausea and/or vomiting

• Sudden loss of sight

SEE RELATED: Glaucoma vs. cataracts: Understanding the difference

Macular degeneration vs. glaucoma

Although macular degeneration and glaucoma are separate disorders affecting different parts of the eye, they are related in a number of ways:

• Research published in 2017 found that people with macular degeneration who are taking medication to preserve their vision might be at greater risk of developing glaucoma.

• Studies released in 2015 and 2016 showed a genetic link between macular degeneration and glaucoma.

• Macular degeneration and glaucoma can occur at the same time, leading to the potential loss of both central vision and peripheral vision. According to the Glaucoma Research Foundation, however, they don’t “actively” affect each other. 

A number of steps can help prevent macular degeneration and glaucoma. They include: not smoking, getting regular exercise, sticking to a healthy diet, and maintaining a healthy weight.

For both macular degeneration and glaucoma, regularly scheduled eye exams are essential to prevent or reduce vision loss. If it's been more than two years since your last eye exam, schedule one today.

DO YOU HAVE ANY SYMPTOMS OF EYE DISEASE? Find an eye doctor near you and schedule an appointment.

Page published on Saturday, June 20, 2020