What Are Red Eyes?
Red eyes, also known as “bloodshot eyes,” happen when the tiny blood vessels on the surface of the whites of your eyes expand, turning the whites of one or both eyes a pink or reddish tint.
The redness can appear in one eye or both. Your eyes can develop redness gradually or all at once.
Why Are My Eyes Red?
Multiple conditions cause red eyes. Some of the most common are:
Allergies
Outdoor triggers include pollen from grasses and trees. Indoor ones include pet dander, dust, and mold. In these cases, your eyes may also:
Itch
Burn
Tear up
You could also have nasal allergy symptoms, such as sneezing and a stuffy nose.
Red eyes are usually nothing to worry about, as long as they don’t happen often and don’t last long. (Photo Credit: iStock/Getty Images)
Dry eye
Sometimes, your tears don’t have the texture they should. They might evaporate too fast. And sometimes, your eyes can’t make tears at all. This condition is called dry eye. It can cause pain, ulcers on your cornea, or, in rare cases, some vision loss.
Other symptoms of dry eye include:
A gritty feeling
A burning feeling
Blurry vision
Heavy eyelids
Not being able to cry
Eye fatigue
Excess tears, at times when your eyes aren’t dry
A stringy discharge
Discomfort with contact lenses
Pinkeye
Also known as conjunctivitis, pinkeye is when the lining of your eyelid and the white of your eye become inflamed. It might happen because of a virus or bacteria. It’s very common, especially among children, and is usually very contagious. If you think you have pinkeye, see your doctor, wash your hands often, and don’t rub your eyes.
Pinkeye can be caused by:
Allergies. These typically affect both eyes and are caused by a response to an allergen such as pollen, producing itchy, watery eyes and inflammation.
Environmental irritants. A foreign object or chemical irritant in your eyes can cause a watery or mucous discharge.
Viruses. Cold viruses are a regular culprit, but other viruses including herpes and shingles can cause pinkeye too.
Bacterial infections. These can be a side effect of colds, but unsterilized contacts can introduce bacteria too. Both the viral and bacterial versions of pinkeye are very contagious.
Related:
3 Signs You Should See a Doctor for Your Dry Eyes
Haemophilus influenzae (H. influenzae). In infants and children, this bacteria can produce pneumonia and may cause eye infections including pinkeye.
Other symptoms include:
More tears than usual
Eyes that burn, itch, or feel gritty
A white, yellow, or green discharge from your eyes
Sensitivity to light
A crust on your eyelid or eyelashes
Broken blood vessels
This happens when tiny blood vessels break beneath the surface of your eye. The blood is trapped and makes the white of your eye turn bright red. It can be caused by a strong sneeze, heavy lifting, hard vomiting, or rubbing your eye a little too hard. You may be more likely to have broken blood vessels, also known as a subconjunctival hemorrhage, if you take blood-thinning medication, even a baby aspirin. Broken blood vessels can look scary but are generally harmless. There’s usually no pain.
Broken blood vessels cause other symptoms like:
A bright red area on your eye along with the general redness
A scratchy feeling
Glaucoma
Fluid can build up in the front part of your eye. This causes pressure and can damage your optic nerve. The condition is called glaucoma. It’s the leading cause of blindness for people 60 and over.
Glaucoma is usually painless. An unusual form of acute glaucoma (angle-closure glaucoma) can cause symptoms such as:
Severe pain in your eye
A headache
Decreased or blurred vision
Rainbows or halos in your vision
Nausea and vomiting
Episcleritis
Episcleritis is an inflammation of the episclera, a thin layer of clear tissue on top of the white part of your eye, or sclera. This is the layer between the thin “skin” of the eye and the tough wall of the eyeball.
When the tiny blood vessels in the episclera get irritated or inflamed, they make your eye look red or bloodshot. It usually happens in just one eye but can affect both.
Though the redness may look like pinkeye, there’s no goopy discharge.
There are two types:
Simple: This is the most common. It has two subtypes:
Sectoral. The redness appears over part of your eye.
Diffuse. The redness appears over all of your eye.
Related:
Tips to Soothe Dry Eyes
Nodular: This is when a tiny bump (or nodule) forms on your eye. This kind tends to cause more discomfort.
Other causes
Other causes of red eyes include things in the world around you, such as:
Chlorine from swimming pools
Dust
Cigarette smoke
Perfume
Damage to your cornea by ultraviolet rays (photokeratitis)
Ocular rosacea
Alcohol or marijuana use
Also, eye conditions like:
A scratch, infection, or ulcer on your cornea
Cornea inflammation (keratitis)
Eyelid inflammation (blepharitis)
Inflammation of the colored part of your eye (iritis), the middle layer of your eye (uveitis), or the white part of your eye (scleritis)
Chalazions, tiny lumps caused by a blocked or swollen oil gland in the eyelid
Styes, an infection of the oil gland
Eye injury
Complications from eye surgery or contact lens use
Over-the-counter eyedrops that target redness can actually make the problem worse. Your eyes might come to depend on the drops and be even redder after they wear off. They can also dry out your eyes and hide symptoms of health problems.
