Eye Health More Eye Issues & Safety Print 18 Reasons You May Have Red and Bloodshot Eyes By Troy Bedinghaus, OD Updated August 17, 2019 Medically reviewed by a board-certified physician More in Eye Health More Eye Issues & Safety Glaucoma Cataracts Macular Degeneration Vision Loss Dry Eye Syndrome Contact Lenses Glasses Exams & Procedures Vision Improvement Surgery Eye Anatomy Kid's Eye Health View All The term "red eye" is used to describe red, bloodshot eyes. Bloodshot eyes are usually painless and develop when blood vessels near the surface of the eye become enlarged and dilated. Some culprits can cause your eyes to feel inflamed and irritated, so you may find yourself seeking relief from your eye doctor. Many people suffer from red eye every once and awhile, but a red eye is not normal. If you've ever had bloodshot eyes, you may have wondered what you did to cause your eyes to become so irritated. Below are a few common causes. And while it is always best to seek the advice of your eye doctor, you may want to try a few red eye home remedies first, at least to get a little relief. Illustration by Brianna Gilmartin, Verywell 1 Dry Eye Syndrome A common cause of bloodshot eyes is dry eye syndrome. It occurs when there are not enough natural tears to keep the front part of the eye lubricated. When your eye becomes dry, it also becomes very red and irritated. Dry eyes can occur if you stare at the computer screen for an extended amount of time, if you don't get enough quality sleep, or if you wear your contact lenses for too long. You can also develop dry eyes from medications you take chronically. Hormonal changes occurring inside your body can also cause your eyes to become dry and irritated. Dry eyes can also develop if the glands that produce tears are plugged up with sweat and oil. What to DoIf your eyes are red and bloodshot due to dry eye syndrome, it might be helpful to instill lubricant eye drops into your eyes. Lubricant, or rewetting eye drops, are sold over the counter and can be used throughout the day. 2 Pink Eye Some cases of red eye are caused by pink eye, also known as conjunctivitis. It is an inflammation or infection of the clear, protective layer that coats the front part of the eye. Pink eye can be caused by allergies, bacteria, viruses, or toxic substances. It is very common but is usually not serious. What to Do Visit your doctor if you suspect you have pink eye. They'll be able to determine if the cause is bacterial, in which case they'll prescribe special antibiotic eye drops. Note that bacterial pink eye is best treated with antibiotics. 3 Blepharitis Blepharitis causes inflammation of the eyelid and eyelashes and may be caused by poor eyelid hygiene. Oily eyelid glands, allergic reactions, bacterial infections, or lice on the eyelashes are also common causes of blepharitis. If you have blepharitis, you may notice a gritty or burning sensation in your eyes, excessive tearing, itching, red and swollen eyelids, dry eyes, or crusting of your eyelids. The condition is not contagious and usually does not cause permanent damage to your eyesight. What to Do Good eyelid hygiene is important, including regularly cleaning the lids and lashes and eyelid scrubs. If you find that this doesn't help, see your doctor for possible antibiotics or medications. 4 Uveitis Uveitis, an inflammation of the eye's uvea, can cause redness, pain, blurry vision, floaters, and light sensitivity. Symptoms of this condition can occur suddenly and get worse very quickly. What to Do Uveitis should be treated quickly because other complications, such as uveitic glaucoma or retinal and choroidal scarring, may occur if it lingers. Your doctor will most likely prescribe a form of steroids to help reduce inflammation. If he or she is able to determine the underlying cause for the uveitis, treatment for that cause will be in order as well. 5 Frequent Use of Eye Drops Do you reach for eye drops when you wake up to red eyes? Surprisingly, frequent use of "get the red out" eye drops can actually make the eyes appear even redder. The chronic use of these eyedrops can cause “rebound dilation” of the blood vessels in the eyes, causing the eyes to appear even more bloodshot. Before instilling eye drops of any kind, it's a good idea to first consult with your eye doctor to identify the cause of your red eyes. 6 Contact Lens Wear Wearing contact lenses can sometimes cause eye redness. In some people, simply having a contact lens in the eye is enough to make the eye red. What to Do If you experience discomfort while wearing contact lenses, you may want to try re-wetting drops. These eye drops are formulated for contact lenses and can provide relief for dry eyes and discomfort associated with contact lens wear. 7 Injury Redness sometimes occurs with an eye injury. Injuring your eye could be as simple as sticking yourself with a mascara wand or accidentally wiping your eye with a sharp fingernail. When you injure your eye, blood vessels inside the eye enlarge and dilate to bring blood and cells to heal and repair the injury. A red eye resting from an injury is also a warning sign to let you know that something is wrong with your eye. Visit your doctor to make sure that you did not harshly damage your eye. 8 Corneal Ulcer or Infection If the eye's cornea becomes infected, nearby blood vessels become enlarged and swollen as cells rush in to help fight the infection. These cells can cause visible redness. This occurs because the cornea is avascular, meaning normally, the cornea does not have any blood vessels in it. It gets most of its oxygen and nutrients from the tears and outside atmosphere. With a corneal infection, the nearby blood vessels enlarge to get important inflammatory cells to the site quickly. What to Do Corneal ulcer treatment needs to be aggressive in order to prevent potential vision loss and blindness. Treatment usually involves antibiotics as well as antiviral or antifungal medications or steroids. 9 Subconjunctival Hemorrhage A subconjunctival hemorrhage causes the white part of the eye to become completely red. It occurs when one of the blood vessels bursts or breaks underneath the conjunctiva, the transparent, clear tissue that covers the white part of the eye. The blood has no place to go, so it spreads out, like ketchup under plastic wrap. If the vessel bleeds a lot, the blood can create a bulbous subconjunctival hemorrhage in which the blood gathers so much that the eye appears swollen and pouches outward. A subconjunctival hemorrhage can look very scary, but it usually does not cause permanent harm to the eye. Straining too hard, lifting something too heavy, sneezing and coughing too hard are common culprits. What to Do Blood in your eye can be scary-looking, but it is usually no cause for alarm, especially if you aren't experiencing pain or visual changes. However, do schedule an appointment with your eye doctor. He or she will examine your eye and make sure that no other damage is present. Measuring your eye pressure and looking inside your eye may also be helpful for ruling out further damage. 10 Acute Angle-Closure Glaucoma Sometimes a red eye can signal a serious condition. One very serious eye condition that may cause red eye is acute angle-closure glaucoma, which is a serious medical emergency that must be treated immediately. It occurs when the fluid pressure inside the eye rises quickly. This serious type of glaucoma usually causes sudden redness in the eye, severe eye pain, and blurred vision (usually occurring in only one eye). Make sure to visit your doctor as soon as possible. 11 Episcleritis Another condition that can give you a bloodshot appearance is episcleritis. This is an inflammation of the thin clear layer of tissue that lies between the conjunctiva and sclera. Episcleritis causes mild eye pain and irritation along with eye redness. Sometimes the eyes become tender to the touch. What to Do Although it may go away on its own, topical steroids are often needed. 12 Allergies Your eyes can become bloodshot because of allergies. Red eyes associated with burning and itching are often caused by allergies. The eyes become red because the blood vessels in the front part of the eye dilate and become larger. Fluid accumulates and causes swelling. What to Do Standard allergy treatments can help reduce eye redness. Your doctor may also have recommendations based on your specific situation. 13 Pregnancy Pregnancy causes big changes to several hormones in the body. These changes can cause the body to produce fewer tears, so your eyes may feel irritated or gritty. They may appear red and sensitive to light. What to Do It may be challenging to wear contacts during pregnancy. Many pregnant women opt for glasses until after they give birth. 14 Computer Vision Syndrome Red, dry eyes result from a lack of moisture to the eyes. Your tears work to replenish moisture to the eyes by blinking. Blinking is one of the fastest reflexes of the body. However, people tend to blink about half as much as normal when they are working on a computer. What to DoTry to reduce redness by blinking more often. Also, replenish moisture in the eye by using artificial tears. 15 Smoking Smoking a cigarette releases several harmful chemicals including formaldehyde, ammonia, and hydrogen sulfide. These chemicals are irritating to the sensitive membranes of the eyes, causing inflammation and "bloodshot eyes." Smoking can also increase the risk of cataracts, a cloudiness in the lens of the eye. 16 Swimming Many people develop red eyes after spending some time in a pool. Redness occurs when blood vessels near the surface of the eye become enlarged and dilated. Chlorine used in pools can also cause the eyes to become irritated. If you're prone to getting red eyes from swimming, wearing swim goggles in the pool is a good option. 17 Lack of Sleep If you don't get enough sleep, your eyes may show it. Losing sleep tends to increase the retention of blood and fluid around the eyes, making them appear puffy and red. Lack of sleep can also lead to dry eyes. Eyes need a constant supply of tears to function properly, which is why blinking is so important. Not allowing the eyes to close for a long night prevents eyes from getting proper fluid circulation. Your eyes need fluid in order to clean and renew. Staying awake too long is not a good idea for overall eye health. 18 Alcohol Drinking alcohol can cause some people to develop eye redness. Alcohol can cause vasodilation, causing the vessels on the white part of the eye to become larger and more visible. Also, alcohol is dehydrating and can causes the eyes to appear red and tired. A Word From Verywell A bloodshot eye can appear with simply a few visible red blood vessels or can be completely red. There are many reasons why your eye may appear bloodshot, but in most cases, it is red for a reason. It is best not to overlook a bloodshot eye—your eye and your body are trying to tell you something important. If you develop bloodshot eyes, it's a good idea to have your eye doctor determine the cause, even if it is harmless, like in many cases. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Sheppard AL, Wolffsohn JS. Digital eye strain: prevalence, measurement and amelioration. BMJ Open Ophthalmol. 2018;3(1):e000146. doi:10.1136/bmjophth-2018-000146 Javadi MA, Feizi S. Dry eye syndrome. J Ophthalmic Vis Res. 2011;6(3):192-8. Solano D, Czyz CN. Viral Conjunctivitis. StatPearls Publishing. Updated November 18, 2018. Karabela Y, Yardimci G, Yildirim I, Atalay E, Karabela SN. Treatment of Phthiriasis Palpebrarum and Crab Louse: Petrolatum Jelly and 1% Permethrin Shampoo. Case Rep Med. 2015;2015:287906. doi:10.1155/2015/287906 Putnam CM. Diagnosis and management of blepharitis: an optometrist's perspective. 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Nutrients. 2010;2(8):781-9. doi:10.3390/nu2080781 Additional Reading 1.Wu, Brian. "Red eyes: List of common causes." Medical News Today, 4 Mar 2017. 2. Chaudhary, Omar R, MD. "What causes red eye?" Eyesmart, American Academy of Ophthalmology, 17 June 2015.