What's the Difference Between Glaucoma and Cataracts?
Millions of Americans suffer from glaucoma and cataracts. They can impair your vision and eventually lead to blindness.
While both lead to vision loss and blindness, cataracts and glaucoma are two distinct eye conditions. Each affects certain parts of the eye. They are also associated with different causes and symptoms.
What is Glaucoma?
In a healthy eye, the lens projects light to the retina, which sends nerve impulses to the brain. Your visual cortex (located at the back of your brain) then interprets them as images.
These impulses travel via the optic nerve. Damage from ocular hypertension can lead to vision loss and blindness.
Signs That You Have Glaucoma
Your signs and symptoms will depend on the type of glaucoma and the severity of your condition.
There are two types of glaucoma:
1. Primary open-angle glaucoma (POAG)
It affects 4 million Americans, making it the most common type of glaucoma. Symptoms include:1
- Peripheral vision loss
- Decreased visual acuity
Open-angle glaucoma causes gradual vision loss that begins on the sides. Unfortunately, most people won't know they have it until they lose their central vision.
2. Acute angle-closure glaucoma (AACG)
Also known as narrow-angle glaucoma or acute glaucoma, it is a rare form of glaucoma with the following symptoms:2
- Severe eye pain
- Frequent headaches
- Blurry vision
- Nausea or vomiting
- Seeing colorful halos around lights
Angle-closure glaucoma causes noticeable symptoms that quickly develop. They can cause immediate damage to the optic nerve and lead to rapid vision loss.
What are Cataracts?
A cataract is a cloudy formation that appears on your eye lens. In a healthy eye, the lens should be clear.
The eye lens consists of proteins that break down with old age. This causes cataracts to form on the surface of your lens.
Signs That You Have Cataracts
Cataracts develop slowly and will not affect your eyesight early on. As it progresses, you may experience:
- Blurry or cloudy vision
- Double vision
- Sensitivity to light or glare
- Poor night vision
- Seeing halos around lights
If you have a cataract, your color perception may change. Colors will appear faded or more yellow. You may also feel the need to use more light when reading or performing activities.
Glaucoma and cataracts are among the leading causes of blindness in elderly Americans.3
Do I Have Cataracts or Glaucoma?
Glaucoma and cataracts are different eye disorders with some similarities and differences:
How Glaucoma and Cataracts are Similar
Here's what glaucoma and a cataract have in common:
- Both are age-related. Your risk begins at the age of 40 and will continue to increase as you age.
- More common in women. About 61% of American women have them, compared to 39% of men.4,5
- Similar symptoms. Both can affect one or both eyes and cause blurred vision, night blindness, and dim vision.6,7
- Both are preventable. Early detection can help your eye doctor keep them from getting worse.
How Glaucoma and Cataracts are Different
Here are the differences between glaucoma and a cataract:
- Prevalence. Black Americans have a higher risk for glaucoma. White Americans are at most risk for cataracts.
- Affects different parts of your eye. Glaucoma affects the optic nerve, while cataracts affect the eye lens.
- Progression of symptoms. Cataracts are painless and develop slowly. Glaucoma can progress gradually with no early signs, or it can be painful and develop quickly.
- How they impair eyesight. A cataract blurs your vision and causes you to see in double. But glaucoma causes you to lose your eyesight.
- How soon you should get treatment. Cataract treatment can wait until it causes major problems. Glaucoma is a medical emergency that needs to be treated right away.
- Available treatments. Surgery and laser treatment are your only options for cataracts. With glaucoma, you can choose from surgery, laser treatment, prescription medications, and eyedrops.
- Treatment outcome. Blindness caused by cataracts is reversible with cataract removal, regardless of how bad it is. Glaucoma treatment doesn't reverse its symptoms but can prevent further vision loss.
Which is Worse — Glaucoma or Cataracts?
None of these conditions are worse than the other. Both glaucoma and cataracts lead to vision loss if left untreated.
For these reasons, we recommend that you visit an ophthalmologist as soon as you notice any vision changes.
The doctor can perform a routine eye exam to diagnose your condition. From there, they can help you explore treatments. If you happen to be in a medical emergency, they can provide immediate treatment.
Acute glaucoma is an ocular emergency. Without treatment, it can cause irreversible blindness.
Do Cataracts Affect Glaucoma and Vice Versa?
Cataracts do not cause glaucoma. That said, they can increase your risk for elevated eye pressure and glaucoma.
Glaucoma also does not cause cataracts. But certain glaucoma surgeries can put you at risk of developing cataracts.
Cataracts and Your Risk for Glaucoma
A cataract starts as a thin membrane that forms on the lens surface. As it worsens, it becomes cloudier and thicker.
Cataracts can push the iris back to the trabecular meshwork — a spongy tissue that drains the aqueous humor. If this gets blocked, it prevents any excess eye fluid from draining.
This causes pressure to build up inside your eye, leading to angle-closure glaucoma. In these cases, you can undergo cataract surgery to reduce any symptoms of glaucoma and treat your cataract. Though you may still need additional treatments to restore normal intraocular pressure.8
Glaucoma Treatment and Cataracts
Doctors treat glaucoma by reducing eye pressure. Some treatment options include a surgery called trabeculectomy and fluid drainage devices like tube shunts.
Unfortunately, they can lead to cataract development.9
When You Have Cataracts and Glaucoma
Even though they are completely different eye diseases, it's possible to have both conditions at the same.
Your eye doctor will likely recommend cataract surgery and combine it with glaucoma treatments such as:
- Glaucoma drainage devices
- Micro-invasive glaucoma surgeries (MIGS)
Sometimes, cataract removal is enough to reduce eye pressure without glaucoma surgery.10
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