10 Causes of Bloodshot Eyes and How To Treat Them

Your eyes can be one of the ways your body tells you something is wrong. Red, bloodshot eyes can indicate issues like a lack of sleep, contact lens irritation, or a stye. Here's what you should know about what causes red eyes to determine better why your eyes may look bloodshot and how to treat them.

1. Alcohol Use

After you drink a lot of alcohol, you may notice bloodshot eyes if you have a hangover. That's alcohol's effect on the eyes. 

Alcohol causes the tiny blood vessels in the eyes to dilate—so more blood flows through them. "The more you drink, the more visible and red they appear against the whites of your eyes," Jessica Lee, MD, assistant professor of vitreoretinal surgery, department of ophthalmology at the New York Eye and Ear Infirmary of Mount Sinai, told Health.

Treatment

OTC eye drops can reduce redness. Also, as the alcohol leaves your system, the blood vessels will return to normal over time.

2. Allergies

An allergic reaction can make your eyes feel itchy, tender, and watery. It can also trigger a blotchy redness, which worsens if you scratch your eyes.

Almost anything can set off a reaction, but common allergens are dust, pollen, and pet dander.

Treatment

Figuring out what caused the reaction, and avoiding exposure to it, will help the redness start to go away. You can also:

• Take antihistamine medications
• Use a cool compress or washcloth over closed eyes
• Use over-the-counter (OTC) eyedrops designed for allergies

3. Corneal Injuries

You may have red eyes because of damage to your cornea, the front clear part of your eye that helps focus light.

If you have a scratch or scrape on your cornea, it's known as a corneal abrasion. Causes can include eye rubbing, fingernails, or dry eyes. Cuts on the cornea, which can come from something sharp getting into the eye, are considered corneal lacerations.

Treatment

Corneal abrasions may require wearing a patch or special contact lens. An ophthalmologist, or a medical eye doctor, may also recommend moisturizing or antibiotic eye drops. The abrasion may heal between one to two days or up to a week, depending on the abrasion's size.

If you have a corneal laceration, seek medical attention. Surgery is the typical treatment to prevent the eye from further damage and remove foreign objects from the eye.

4. Glaucoma

Glaucoma damages the optic nerve when fluid puts too much pressure on the eye. The optic nerve connects the eye's retina to the brain.

One of the first signs of one type of glaucoma—called angle-closure glaucoma—is redness. Other signs include:

• Cloudy vision
• Inner eye pain
• Nausea and vomiting
• Seeing halos around lights
• Swollen eyes

Treatment

Treatment can vary depending on the type of glaucoma you have. You may be treated using the following:

• Eye drops
• Laser treatment
• Pills or IV medication to lower inner eye pressure
• Surgery

Glaucoma can cause blindness, so you must see an eye care provider for a complete exam if you suspect you may have it. Immediate medical care is necessary for severe eye pain or sudden vision loss.

5. Irritation From Contacts

If you wear contact lenses, it's essential to use and care for them properly. Not doing so can lead to eye redness.

"Contact lenses can prevent enough oxygen from reaching your eyes, leaving you with bloodshot and irritated eyes," explained Dr. Lee. "If the lenses are worn too long or worn while sleeping, they can cause redness, infections, and in worst-case situations, corneal ulcers."

Treatment

Remove lenses, but don't discard them, and see an eye care provider as soon as possible if you experience contact lens irritation.

Additionally, you can prevent irritation issues by:

• Closely following the lens care directions and cleansing them properly
• Practicing good contact lens hygiene
• Taking the contacts out before falling asleep

6. Keratitis

Contact lens irritation may also be connected to keratitis, another cause of eye redness. Keratitis, also called a corneal ulcer, is an open corneal sore. These ulcers may result from infections, corneal abrasions, dry eye syndrome, or eyelid disorders.

Treatment

See an eye care provider if you believe you have keratitis. Untreated ulcers can result in vision damage or blindness.

Ophthalmologists may prescribe eyedrops depending on the type of germ—bacteria, fungus, or viral—that caused the ulcer. Anti-inflammatory eye drops and pain medications might follow the antibiotic, antifungal, or antiviral eye drops. In some cases, surgery could be necessary for scarring or to maintain vision.

7. Lack of Sleep

Tired eyes from a lack of sleep tend to be bloodshot eyes. "If your eyes are kept open for a long time because of lack of sleep, it prevents the cornea [the surface of your eye] from being well lubricated, which can cause dryness and redness," explained Dr. Lee.

In one study, researchers reported a positive correlation between people with sleep deprivation and dry eyes.

Treatment

Getting more sleep, if and when possible, can treat eye redness due to tiredness. OTC eye drops and cool compresses can also help.

8. Pink Eye

Your bloodshot eyes might be pink eye. "Pink eye is the non-medical term for conjunctivitis—a bacterial, viral, or allergy-induced infection that leaves one or both eyes bright red, swollen, teary, and itchy," explained Dr. Lee.

Though it rarely becomes serious, pink eye spreads quickly. It can turn your eyes goopy and pinkish-red and keep you from work for several days.

Treatment

Pink eye doesn't require a visit to a healthcare provider. However, seek medical attention if:

• Eye pain becomes severe or worsens
• A headache, light sensitivity, or vision changes accompany eye redness
• The infection doesn't go away in a few days
• You have eyelid or eye area swelling and redness
• You're unsure if you have pink eye

Also, your pink eye type will determine how and if a healthcare provider can treat it. For example, if it's a bacterial infection, antibiotic eyedrops can help.

9. Stye

A stye is a small red bump that forms on your eyelid (or the bottom edge of your eye) after an oil gland becomes plugged up.

You could have one or several, and each will resemble a pimple. One of the first signs is redness, along with swelling and sensitivity. Bacteria cause styes, and almost everyone will have styes at some point.

Treatment

A stye doesn't affect your vision, but it can still be bothersome. Getting rid of it generally involves waiting and letting it disappear in several days.

Touching the stye can worsen it, so avoid popping it. That can also exacerbate the infection. If you get styes frequently, see an ophthalmologist, who may prescribe an antibiotic ointment.

10. Subconjunctival Hemorrhage

A subconjunctival hemorrhage happens when a blood vessel under the eye's surface breaks. When that happens, blood gets trapped and forms a bright red patch in the white of the eye. 

Treatment

Subconjunctival hemorrhage doesn't require treatment. Though hemorrhage looks serious, it won't likely affect vision or cause pain, discharge, or swelling. The red patch usually fades over a few weeks.

A Quick Review

Conditions like allergies, corneal injuries, and styes can cause red, bloodshot eyes. Several of those are usually cleared up by a quick course of antibiotics or even a few eye drops. However, depending on the cause, you may need more or no treatment.