What are the 7 causes of blindness

Blindness—basically not having useful vision—hits millions of people around the world. The reasons differ depending on where you live and how old you are, but seven main conditions are behind most cases of vision loss, whether it's preventable or not. Knowing these is the first real step toward stopping it or catching it early.

The 7 Leading Causes of Blindness

These seven are the big ones, the most common routes to blindness globally. The World Health Organization and top eye doctors agree on this list.

• Cataracts: Your eye's natural lens gets cloudy. This is the number one cause worldwide, over half of all cases. Good news: surgery can fix it.
• Glaucoma: A bunch of eye diseases that hurt the optic nerve, usually from high pressure inside the eye. It's a major reason for permanent blindness, in older folks.
• Age-Related Macular Degeneration (AMD): Hits the macula, the center of your retina, messing up your central vision. In rich countries, it's the top cause of blindness for people over 50.
• Diabetic Retinopathy: A diabetes complication where blood vessels in the retina get damaged. It's a big reason working-age adults go blind.
• Trachoma: A bacterial infection that scars the cornea. Easily treated with antibiotics, but still a leading cause of preventable blindness in poor countries.
• Corneal Opacity: Scarring or clouding of the cornea from infection, injury, or not enough vitamin A. Hits kids and adults in low-income areas hard.
• Retinopathy of Prematurity (ROP): Weird blood vessel growth in the retinas of babies born too early. A leading cause of childhood blindness, but mostly avoidable with proper screening.

What is the most common cause of blindness?

Cataracts take the crown, accounting for about half of all blindness worldwide. And it's fixable—a simple surgery swaps out the cloudy lens for an artificial one. Why so common? Mostly because we get older, and the lens just naturally goes opaque over time.

Can blindness be prevented?

Absolutely. A huge chunk of blindness—the WHO says up to 80%—is either preventable or treatable. Here's what helps:

• Get your eyes checked regularly, especially if you're over 40 or have diabetes.
• Catch stuff like glaucoma and diabetic retinopathy early and manage it.
• Get vaccinated against things like rubella (it can cause cataracts from birth).
• Keep clean and practice good hygiene to dodge trachoma.
• Treat eye injuries and infections right away.
• Make sure cataract surgery is available in places that lack it.

What are the early warning signs of blindness?

It depends on the condition, but some symptoms scream "see a doctor now":

• Vision getting blurry, either suddenly or slowly.
• Losing your side vision.
• Seeing flashes of light or floaters.
• Struggling to see at night or in dim light.
• Eye pain, redness, or pressure.
• Seeing double.
• A curtain-like shadow covering part of what you see.

If any of this sounds familiar, don't wait—talk to an eye doc immediately.

Data Table: Leading Causes of Blindness by Region

FAQ: What are the 7 causes of blindness?

Checklist for Protecting Your Vision

• Get a full eye exam every 1-2 years after you turn 40.
• Keep your blood sugar and blood pressure in check if you have diabetes or high blood pressure.
• Wear sunglasses that block UV to protect against cataracts and AMD.
• Don't smoke—it doubles your risk for AMD and cataracts.
• Eat of leafy greens, omega-3s, and antioxidants.
• Use protective eyewear for sports or risky work.
• Know your family's history of eye diseases.