Red eyes can be the sign of a minor irritation or a serious medical condition, such as an infection.

Bloodshot or red eyes occur when small blood vessels that are present on the surface of the eye become enlarged and congested with blood. This happens due to an insufficient amount of oxygen being supplied to the cornea or the tissues covering the eye.

Bloodshot eyes by themselves are generally not a reason to be overly concerned, but when coupled with eye pain, abnormal drainage, or impaired vision this can indicate a serious medical problem.


Conjunctivitis is also known as pink eye and is mostly caused by viruses, which may be spread by the hands.

Conjunctivitis, commonly known as pinkeye, is an infection that includes swelling and irritation of the conjunctiva. The conjunctiva is a thin transparent membrane that lines the eyelid and loops back to cover the the white part of the eye.

An infection of the conjunctiva irritates the blood vessels causing them to swell up. It is this inflammation that makes the whites of the eyes appear reddish or even a bit pink.

Viruses cause up to 80 percent of all cases of conjunctivitis. Pink eye is prevalent among school children and is very contagious.

The infection is commonly spread through direct contact with contaminated fingers or personal items. It is often associated with an upper respiratory infection and spread through coughing.

Allergic conjunctivitis can be due to an allergy or an irritant such as dust. Wearing contact lenses for too long or not properly cleaning them can also lead to conjunctivitis. Conjunctivitis caused by allergies or irritants is not contagious.

People usually end up getting pink eye in both eyes because an infection can easily spread from one eye to the other. Signs and symptoms of conjunctivitis include:

  • itchy eye
  • excess tear production
  • redness
  • discharge
  • light sensitivity
  • poor vision
  • gritty feeling in one or both eyes

A doctor can typically spot conjunctivitis due to the telltale reddish-pink eye or by the type of discharge present. People with bacterial conjunctivitis may not have the red eye but are likely to have a distinctive mucus discharge or drainage that is white, green, or yellow.

To confirm the diagnosis, a doctor may do a full eye examination or take a sample of any eye discharge for laboratory analysis.

If the outbreak is due to an allergy, a doctor may order an allergy test to determine the specific allergen that the person needs to avoid.

Treatment options for conjunctivitis depend on the type, so it is important to see a doctor if experiencing any of the signs and symptoms. Pink eye is not a serious condition and it does not typically cause any long-term vision problems. It will often clear up on its own.

To avoid spreading conjunctivitis, people should wash their hands frequently and avoid rubbing their eyes. They should also avoid sharing eye drops, cosmetics, towels, or pillowcases.

After bacterial or viral conjunctivitis clears up, people should dispose of any contact lenses, solutions, or eye makeup they used while they were infected to help avoid re-infection.

Corneal ulcer

A corneal ulcer is an open sore on the cornea that is typically caused by bacterial infections. They often appear following an eye injury, trauma, or some other type of damage.

Man rubs eyes at work
Symptoms of a corneal ulcer may include soreness of the eyes and sensitivity to the light.

Symptoms can include:

  • red eyes
  • pain in the eye
  • soreness of the eye
  • sensitivity to light
  • mild to severe eye discharge
  • reduced vision
  • a white spot on the cornea

People with eyelid disorders, cold sores, and who wear contact lenses are at risk of developing corneal ulcers. Eyes are very susceptible to irritation from contact lenses, especially if the lenses are not handled safely, stored correctly, or cleaned properly.

Contact lenses can rub against the eye’s surface and slightly damage the outer cells. This damage may allow bacteria to penetrate the eye.

Other causes of corneal ulcers include:

  • fungi
  • parasites
  • viruses
  • dry eyes
  • allergies
  • widespread infection
  • abrasions or burns to the cornea
  • Bell’s palsy

If not treated properly, corneal ulcers can lead to severe vision loss or even loss of an eye.

Treatment options include antibiotics or antifungal agents. Special eye drops may be prescribed to help ease pain and reduce the chance of complications. Serious cases may require a cornea transplant.

Dry eye syndrome

A person who does not produce enough tears, or tears of good enough quality to lubricate and nourish their eyes properly, is said to suffer from dry eye or dry eye syndrome.

A medical condition, hormonal changes, and even some medicines can cause dry eye syndrome. Chronic dry eye can cause the surface of the eye to become inflamed and irritated, giving the eyes a red appearance. Symptoms of dry eye syndrome include:

  • stinging or burning eyes
  • foreign body sensation
  • pain and redness in the eye
  • excessive tears
  • discomfort when wearing contact lenses
  • blurry vision
  • eye fatigue
  • stringy eye discharge
  • increased discomfort after watching television or reading

Only a doctor can determine if there is an underlying medical condition that is causing the dry eye. An ophthalmologist can perform tests to measure tear production if necessary.

Dry eye is incurable but can be treated. For mild cases, there are over-the-counter medications that may be helpful, such as artificial tears, gels, and ointments. Treatment options include artificial tears, prescription eye drops, or surgery depending on the severity of the condition.

The anti-inflammatory medication cyclosporine is the main prescription currently available to treat dry eye. It helps to decrease corneal damage, increase tear production, and reduce overall symptoms.

Subconjunctival hemorrhage

subconjunctival hemorrhage
A subconjunctival hemorrhage is when blood builds up under the conjunctiva.

The conjunctiva contains many blood vessels and capillaries. These vessels can break and cause blood to leak into the area between the conjunctiva and the white of the eye.

When this happens, a small amount of blood builds up under the conjunctiva. This small accumulation of blood is called a subconjunctival hemorrhage. The minor bleeding under the eye’s outer membrane causes bright red spots to appear on the white on the eye.

Subconjunctival hemorrhages usually occur due to a minor injury or trauma to the eye. Even rubbing the eye too hard can cause a hemorrhage.

The most common causes of subconjunctival hemorrhages are coughing, sneezing, and straining. People who have diabetes, high blood pressure, or who are taking certain medications can also get subconjunctival hemorrhages.

Subconjunctival hemorrhages occur on the surface of the eye. As they do not affect the cornea or the interior of the eye, vision is not affected.

They are typically not painful and cause no sensations, or real symptoms other than the red spots. Though red or blood in the eye can look serious, most subconjunctival hemorrhages are generally harmless and clear up on their own within a few days.

No treatment is typically necessary, but if they become irritated, a doctor may recommend artificial tears.

Other causes

These are just a few common disorders associated with red eyes. Others include:

  • inflammation of the cornea, iris, or white of the eye
  • glaucoma
  • too much sun exposure
  • dust or other particles in the eye
  • injury
  • swimming
  • smoking or drinking
  • environmental irritants or pollutants


Red eyes can develop suddenly or over time. Eye drops are helpful in many cases, and can be purchased over-the-counter or online. If the redness is not easing up and is accompanied by other symptoms, people should see a doctor.

Eye injuries, contact lenses, and frequent use of eye drops can all cause irritation leading to red eyes. A doctor can help a person to pinpoint the cause of their red eye problem and develop a treatment plan.

Common treatments include eye drops, antibiotics, creams, and oral medications. Most conditions are readily treatable and, if caught early, do not cause any permanent long-term damage.

Some serious medical conditions, including leukemia, sarcoidosis, and juvenile idiopathic arthritis, can also cause a red eye. As a result, getting a proper diagnosis is critical.

People should not hesitate to contact their doctor with any questions or concerns if they have red eyes.