Red eyes happen when the blood vessels on the surface of the eye (the conjunctiva) become irritated, which causes them to become enlarged and dilated. This can sometimes be a medical emergency. One of the most common causes of red eyes are allergens and environmental irritants such as pet dander, pollen, dust, wind, dry air, and sun. People who do not get enough sleep will also experience red eyes.

Eye infections and inflammations can cause red eyes, as well as other symptoms such as itching, discharge, pain, and blurred vision. If a contact lens wearer does not keep their lenses clean and disinfected, or wears them for too long, they can experience red eyes. Excessive dryness can also cause eyes to become red and irritated. Other times red eyes can be a red flag, indicating a more serious problem such as blepharitis, conjunctivitis, corneal ulcers, scleritis, or acute glaucoma.

Symptoms of Eye Redness
-- Burning sensation
-- Watery eyes
-- Itchy eyes
-- Itchy eyelids
-- Swollen eyelid
-- Discharge; could be thick or watery
-- Foreign body sensation
-- Photophobia (light sensitivity)
-- Dermatitis (crusting or scaling of the eyelid skin)

Treatment for Eye Redness
In most cases, red, bloodshot eyes will clear up on their own. If you are experiencing bloodshot eyes due to allergies or environmental irritants, you can try using oral antihistamines or over-the-counter eye drops before seeking further medical attention.

This solution often clears up red eyes quickly. Dry eyes usually become red eyes, and artificial tears could be an easy fix to the problem. Rubbing your eyes will only make the situation worse, and can bring on additional symptoms. Avoid touching your eyes altogether, even if you have washed your hands thoroughly. Oil and debris can stick to your fingers or get under your fingernails and cause more redness, and may even scratch your eyeball.