Red eyes (bloodshot eyes)

What are red eyes?

Red eyes (or red eye) is a condition where the white of the eye (the sclera) has become reddened or "bloodshot."
The appearance of red eye can vary widely. It can look like there are several squiggly pink or red lines on the sclera or the entire sclera may appear diffusely pink or red.
Red eye can occur in one or both eyes, and it can be associated with several symptoms, including:

• Irritation
• Burning
• Itching
• Dryness
• Pain
• Discharge
• Watery eyes
• Sensitivity to light
• Blurry vision

In some cases, bloodshot eyes may have no symptoms other than redness.
Red or bloodshot eyes are very common and have many causes. Red eye usually is a symptom of other eye conditions that can range from benign to serious.

What causes red eyes?

The appearance of red eyes is caused by dilation of tiny blood vessels that are located between the sclera and the overlying clear conjunctiva of the eye. These tiny blood vessels (many of which normally are invisible) can become swollen because of environmental or lifestyle-related reasons or because of specific eye problems.
Red eyes usually are caused by allergy, eye fatigue, over-wearing contact lenses or common eye infections such as pink eye (conjunctivitis). However, redness of the eye sometimes can signal a more serious eye condition or disease, such as uveitis or glaucoma.

Red eyes occur when the blood vessels on the surface of the eye expand.

Environmental causes of red, bloodshot eyes include:

• Airborne allergens (causing eye allergies)
• Air pollution
• Smoke (fire-related, second-hand cigarette smoke, etc.)
• Dry air (arid climates, airplane cabins, office buildings, etc.)
• Dust
• Airborne fumes (gasoline, solvents, etc.)
• Chemical exposure (chlorine in swimming pools, etc.)
• Overexposure to sunlight (without UV-blocking sunglasses)

Common eye conditions that cause red eyes include:

• Dry eyes
• Eye allergies
• Pink eye (conjunctivitis)
• Contact lens wear
• Digital eye strain

Serious eye conditions that can cause red eyes include:

• Eye infections
• Eye trauma or injury
• Recent eye surgery (LASIK, cosmetic eye surgery, etc.)
• Uveitis
• Acute
• Corneal ulcer

Lifestyle factors also can contribute to your red eye risk. For example, smoking (tobacco or marijuana) definitely can cause red eyes, as can significant alcohol consumption. Sustained use of digital devices and insufficient sleep are other lifestyle-related causes of red eyes.

How to get rid of red eyes

Because red eye have so many causes (including some that are serious and require immediate attention), you should see your eye doctor right away if you have red, bloodshot eyes — especially if the redness comes on suddenly and is associated with discomfort or blurred vision.
And bring your contacts with you to your appointment so your doctor can evaluate whether your contact lenses are causing your red eyes.