Moderate coffee consumption does not directly cause vision impairment or eye damage. However, heavy caffeine intake may lead to temporary visual disturbances, such as blurred vision or eye twitching, in some people.

According to the Food and Drug Administration (FDA), a single 8-ounce cup of coffee contains around 80–100 milligrams (mg) of caffeine.

A typical person can safely consume up to 400 mg of caffeine per day without experiencing negative or dangerous side effects. This is equivalent to 4–5 cups of coffee.

Visual changes from heavy caffeine intake may be mild and resolve once the body processes the caffeine. However, if the changes persist, a person should speak with a healthcare professional to determine the exact cause and create a treatment plan.

This article discusses the effects of coffee on eyesight, other causes of vision issues, and how to prevent vision loss.

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No scientific evidence suggests that moderate coffee consumption can directly damage eyesight or cause blindness.

When consumed in moderation, coffee is generally safe for overall health. However, heavy consumption of coffee or caffeine may have side effects that could indirectly affect eye health.

Coffee and eye pressure

Coffee contains caffeine, which can temporarily increase intraocular pressure (IOP), the fluid pressure inside the eyes.

According to the National Eye Institute (NEI), elevated IOP is a risk factor for glaucoma. Glaucoma is a group of eye conditions that can lead to optic nerve damage and vision loss.

However, caffeine typically only causes a moderate, temporary increase in IOP, which is unlikely to cause significant harm in people with healthy eyes.

The NEI highlights research suggesting people genetically predisposed to higher eye pressure may have an increased risk of glaucoma if they consume caffeine frequently.

This research suggests that frequent caffeine intake could more than triple the risk of glaucoma for people in this particular population.

Moderate caffeine consumption is generally safe for overall health and will not lead to eye damage.

However, a person who limits their caffeine consumption could still experience eye damage and blindness from other causes.

Factors that can cause blindness and vision loss include:

  • Age-related macular degeneration (AMD): AMD is a progressive eye condition that affects the macula, the central part of the retina responsible for sharp, central vision. It is a leading cause of vision loss in older adults.
  • Glaucoma: If left untreated, glaucoma can lead to permanent vision loss and blindness.
  • Cataracts: Cataracts occur when the eye’s lens becomes cloudy, leading to blurry vision. If not treated, cataracts can cause significant vision impairment and eventually lead to blindness.
  • Diabetic retinopathy: Diabetic retinopathy is a complication of diabetes that affects the blood vessels in the retina. It can cause vision loss and, in severe cases, blindness.
  • Retinal detachment: This occurs when the retina separates from the underlying tissue. It is a medical emergency and can cause rapid vision loss if not promptly treated.
  • Inherited eye diseases: Certain genetic conditions, such as retinitis pigmentosa, Stargardt disease, and Leber congenital amaurosis, can cause progressive vision loss and, in some cases, blindness.
  • Eye injuries: Traumatic eye injuries, such as penetrating injuries or severe blows to the eye, can damage the eye’s structures and result in vision loss or blindness.
  • Infections and inflammation: Infections, such as untreated or severe cases of uveitis, endophthalmitis, or optic neuritis, as well as certain inflammatory conditions, can damage the eye and cause vision impairment.
  • Stroke: A stroke affecting the brain’s visual centers can lead to visual impairment or blindness in one or both eyes.
  • Medications and toxic substances: Certain medications, such as high dose corticosteroids, can cause vision problems. Additionally, exposure to toxic substances, such as methanol or certain chemicals, can damage the optic nerve and result in vision loss.

Since there is no research to suggest that moderate caffeine intake causes blindness, doctors may not recommend altering caffeine intake if a person is experiencing changes in their vision.

Instead, treatments for blindness or eye damage may vary depending on the underlying cause and specific type of eye damage. Some potential treatment options include:

  • Medications: Doctors may prescribe medications to treat eye issues. Some drugs can lower IOP for glaucoma. Anti-vascular endothelial growth factor (anti-VEGF) drugs may treat certain eye problems, such as diabetic retinopathy.
  • Surgery: Surgical interventions vary depending on the eye condition. Some surgical options include cataract surgery, reattachment of the retina, corneal transplants, and corneal reshaping surgeries, such as LASIK.
  • Laser therapy: Laser treatments vary depending on the condition. Laser treatments can alter abnormal blood vessels in the retina or promote fluid drainage in glaucoma.
  • Medication injections: In some cases, doctors may inject medications directly into the eye to treat conditions such as macular degeneration or diabetic retinopathy. These injections help reduce abnormal blood vessel growth and inflammation.

To avoid potential negative side effects, a person may choose to limit their caffeine consumption to 400 mg per day, which is 4–5 cups of coffee. However, there is no research to suggest this limitation is necessary to prevent vision changes.

The Centers for Disease Control and Prevention (CDC) recommends the following steps to help a person maintain eye health and reduce the risk of blindness or eye damage:

  • Regular eye exams: Regular check-ups help detect eye conditions early when they are most treatable.
  • Protect the eyes: Wear appropriate protective eyewear in necessary situations, such as safety glasses or goggles, to prevent eye injuries.
  • Eat a nutritious diet: A diet rich in fruits, vegetables, and omega-3 fatty acids can help a person get the nutrients beneficial for eye health.
  • UV protection: Protect the eyes from harmful ultraviolet (UV) radiation by wearing sunglasses that block both UVA and UVB rays.
  • Quit smoking: Researchers link smoking with an increased risk of various eye conditions, including cataracts, AMD, and optic nerve damage.
  • Manage chronic conditions: Diabetes can lead to diabetic retinopathy when not appropriately treated. Speaking with a healthcare professional can help a person avoid potential blindness.

Can coffee prevent blindness?

A 2017 research review suggests that coffee may be protective against the risk of AMD. Similarly, a 2022 report associates coffee consumption with a reduced risk of diabetic retinopathy.

However, more research is needed to confirm these findings and understand the underlying mechanisms.

According to the American Academy of Ophthalmology, people should speak with a doctor or seek medical attention for their eyes if they experience:

  • persistent or worsening changes to vision
  • new or unexplained symptoms, such as blurry vision, double vision, floaters, or flashes
  • serious injuries to the eye
  • chronic conditions and have concerns about their condition

Moderate coffee consumption is generally safe. It is not known to cause blindness or significant eye damage.

Coffee contains caffeine, which can temporarily increase intraocular pressure (IOP), but the elevation is typically modest and temporary. It is unlikely to cause harm in people with healthy eyes. Regular coffee drinkers may develop tolerance to the effects of caffeine over time.

Heavy caffeine intake or dehydration from heavy coffee consumption may indirectly affect eye health, but they do not have direct links to permanent vision loss or blindness.