Blindness: Symptoms, Causes, and Treatment

Blindness refers to a lack of vision. It can be a symptom of various eye diseases you develop or disorders you've had since birth. You should seek immediate medical attention if you experience a new loss of sight.

This article discusses types of blindness, symptoms related to blindness, potential causes, and treatments.

A young blind woman standing on a train platform holding a white cane

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Seek Immediate Help

Seek immediate medical care if you have a sudden loss of vision in one or both eyes.

Symptoms of Blindness

The symptoms of blindness depend on the type of blindness an individual has.

With complete blindness, symptoms include:

  • No perception of light
  • Vision that can't be corrected with contact lenses or glasses

In most states, legal blindness is vision that is worse than 20/200, even when using glasses or contact lenses. The definition of legal blindness helps determine if a person is eligible for disability benefits.

The use of 20/200 refers to how well you can see an object that is 20 feet away. On standard eye exam charts, your vision is considered 20/200 if the only thing you can read 20 feet away is the big E, even while using contact lenses or glasses.

Another type of blindness is called night blindness. This refers to vision problems at night or in dark environments. Symptoms of night blindness include:

  • Poor vision at night
  • Poor vision in dim lighting
  • Vision that is particularly bad after going from a brightly lit area to a dark area

Color blindness, another type of blindness, refers to an inability to distinguish between specific colors. Symptoms include:

  • Trouble perceiving the brightness of colors
  • An inability to distinguish between shades of similar colors (this occurs most frequently with red and green or blue and yellow)

Causes of Blindness

The most common causes of blindness in the United States are age-related macular degeneration (AMD), cataract, and diabetic retinopathy.

Age-Related Macular Degeneration

AMD is an eye disorder that is more common with age and affects your central vision. Central vision is what you use for everyday tasks like driving and reading. Although most people with AMD will not go blind from it, it is the leading cause of vision loss among those who are 50 or older.

Cataract

A cataract is a clouding of the lens in the eye. Cataracts become more common with age, although they can occur at any age and even be present at birth. Cataracts are one of the leading causes of blindness around the world.

Diabetic Retinopathy

Diabetic retinopathy occurs in people with diabetes and results from damage to blood vessels in the retina, the light-sensitive tissue located in the back of the eye. Diabetic retinopathy is the leading cause of blindness among American adults.

Other Causes

In addition to AMD, cataracts, and diabetic retinopathy, there are many other potential causes for blindness, including:

  • Glaucoma
  • Eye injury
  • Disorders that are present at birth

What Medications Can Cause Blindness?

Many medications can affect your vision. Some drugs increase the risk for angle-closure glaucoma due to a narrowing of the eye's drainage angle. An acute angle-closure attack can affect your vision suddenly and is a medical emergency.

Medications that increase the risk of this type of attack include:

  • Anticholinergics, which include some of the drugs that treat allergies, depression, and heart disease
  • Drugs with ephedrine
  • Drugs with sulfonamide
  • Oral steroids

Acute angle-closure attacks are more prevalent in females, people of Asian descent, and those with a family history of angle-closure glaucoma.

Glaucoma is another cause of blindness if left untreated. If you have glaucoma, it's important to discuss medication use with your healthcare providers to help avoid drugs that can make glaucoma worse.

How to Treat Blindness

There are emerging treatments that help some specific types of blindness, such as blindness caused by the genetic disorder Leber congenital amaurosis. Yet the majority of treatments for vision loss focus on preserving any remaining vision you have. These treatments vary widely depending on what is causing the blindness.

Age-Related Macular Degeneration

The most common treatment for AMD is a class of drugs called anti-vascular endothelial growth factors (VEGF). These are injected into the eye. Anti-VEGF drugs won't restore the vision that you've lost, but they can help maintain what vision you still have. If you have AMD in one eye but not the other, a special vitamin and mineral supplement called AREDS 2 may help slow down AMD in the other eye.

Cataract

Cataracts are most frequently treated with surgery that removes the cloudy lens and replaces it with an artificial one. Cataract surgery cures the vision loss the cataract causes, although you may still need to wear glasses for some of your vision-related tasks.

Diabetic Retinopathy

Diabetic retinopathy treatment includes anti-VEGF drug injections, lasers, and surgery. The treatments won't restore your vision, but they may prevent further vision loss. You should also do what you can to control your diabetes to help slow diabetic retinopathy.

There are resources that can help you live better with vision loss. Ask your eye doctor about low-vision (visual acuity of 20/70 or worse in your better-seeing eye) devices to help you navigate life better. If you have complete blindness, the same organizations that support those with low vision also help those who are blind.

Complications and Risk Factors Associated With Blindness

Risk factors associated with blindness depend on the cause.

Risk factors for age-related macular degeneration include:

  • Being age 50 or older
  • Having high blood pressure
  • Having a diet high in saturated fat
  • Smoking

Risk factors for cataracts include:

  • Age
  • Diabetes
  • Excessive exposure to the sun without the use of sunglasses
  • Having an eye injury or previous eye surgery
  • Smoking

Risk factors for diabetic retinopathy include:

Are There Tests to Diagnose the Cause of Blindness?

To diagnose what is causing blindness, an eye doctor will conduct an eye exam. Some functions of an eye exam include examining and measuring:

  • How well you see
  • Your eye's anatomy (including the back and front of the eye)
  • How your pupils respond to light
  • Your eye muscles

Your eye doctor will perform other, more detailed tests as needed to pinpoint the cause of blindness.

When to See a Healthcare Provider

Sudden vision loss is rarely painful, so you can't rely on pain as a sign that your vision needs attention. Seek immediate medical care if you suddenly lose vision in one or both eyes.

Summary

Complete blindness means a lack of vision and no perception of light. There are other forms of blindness, including legal blindness, night blindness, and color blindness. The most common causes of blindness in the United States are AMD, cataracts, and diabetic retinopathy. Glaucoma can also lead to blindness if left uncontrolled.

Treatments for the most common causes of blindness help preserve remaining sight but do not restore vision loss. Older age and smoking are risk factors for the most common causes of blindness in the United States. Having diabetes raises the risk of cataracts and diabetic retinopathy.

You should see a healthcare provider immediately if you have sudden vision loss.

Frequently Asked Questions

  • What are types of blindness?

    Types of blindness include complete blindness, partial blindness, legal blindness, night blindness, and color blindness. Congenital blindness refers to blindness that began at birth.

  • What are some of the most common causes of blindness?

    Age-related macular degeneration, cataracts, diabetic retinopathy, and glaucoma are the most common causes of blindness in the United States. Eye injuries, stroke, infection, and complete retinal detachment are other causes of blindness.

  • Will I go blind if I have macular degeneration, diabetic retinopathy, or glaucoma?

    In most cases, no. Although these diseases cause a large percentage of vision loss worldwide, this doesn't mean that most people with these conditions go blind. You can reduce your risk of vision loss by taking regular eye exams and letting your eye doctor know when your vision changes.

  • What are the largest causes of vision loss around the world?

    Uncorrected refractive errors (like myopia or hyperopia), cataracts, and macular degeneration are the most common causes of vision loss worldwide. The causes of blindness vary widely according to the availability of eye care services, affordability, and knowledge.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Blindness and vision loss.

  2. American Foundation for the Blind. Low vision and legal blindness terms and descriptions.

  3. Icahn School of Medicine at Mount Sinai. Vision - night blindness.

  4. American Academy of Ophthalmology. What is color blindness?

  5. Centers for Disease Control and Prevention. Common eye disorders and diseases.

  6. Johns Hopkins Medicine. Age-related macular degeneration.

  7. World Health Organization. Blindness and vision impairment.

  8. BrightFocus Foundation. Medications that may adversely affect glaucoma.

  9. American Society of Retina Specialists. Leber congenital amaurosis.

  10. National Eye Institute. Age-related macular degeneration.

  11. National Eye Institute. Cataracts.

  12. National Eye Institute. Diabetic retinopathy.

By Vanessa Caceres
Vanessa Caceres is a nationally published health journalist with over 15 years of experience covering medical topics including eye health, cardiology, and more.