Bloodshot Eyes Causes and Treatments

Contact Lens Wear

Contact lenses can be irritating to the eyes, causing them to turn red. Some common reasons contacts may irritate your eyes include:

• Poor fit
• Leaving them in too long
• Traumatic removal
• Wearing a damaged contact lens
• Poor hygiene

Sometimes contact lens complications can cause corneal abrasion—a scratch on the cornea that can then become infected and result in an infectious corneal ulcer.

Frequent Use of Eye Drops

Do you reach for eye drops when you wake up with bloodshot eyes? Watch out for drops that include ingredients that constrict blood vessels such as tetrahydrozoline HCL, which decreases oxygen flow to the eye and results in rebound dilation when the drop is stopped.

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 working on a computer. This is known as "computer vision syndrome" or digital eye strain.

Lack of Sleep

If you don't get enough sleep, your eyes may show it. Losing sleep tends to increase blood and fluid around the eyes. This makes them appear puffy and red. Lack of sleep can also lead to dry eyes.

Your eyes need fluid to clean and renew. Unfortunately, when you don't get enough sleep, your eyes don't get the long rest they need for proper fluid circulation.

Swimming

Many people develop bloodshot eyes after spending some time in a pool. Redness occurs when chlorine used in pools causes the eyes to become irritated. As with other causes of bloodshot eyes, this leads blood vessels near the surface of the eye become enlarged and dilated.

If you're prone to getting bloodshot eyes from swimming, wearing swim goggles in the pool is a good option.

Smoking Cigarettes

Smoking a cigarette releases several harmful chemicals that can irritate the sensitive tissues of the eyes. For example, exposure to formaldehyde, ammonia, and hydrogen sulfide can lead to eye inflammation and bloodshot eyes.

Alcohol and Cannabis

Drinking alcohol can cause some people to develop eye redness. This is because alcohol can cause vasodilation, which is when your blood vessels widen.

Vasodilation can cause the vessels on the white part of the eye to become larger and more visible. Also, alcohol is dehydrating and can cause the eyes to appear red and tired.

It's well known that using cannabis causes bloodshot eyes too, whether you smoke the plant or consume it as an edible.

Vasodilation and eye redness happen because they're binding to receptors on the blood vessels on the surface, i.e., the white part of the eye.

Allergies

You can have bloodshot eyes due to allergies. In addition, red eyes from allergies often burn and itch.

With allergies, the eyes become red because the blood vessels in the front part of the eye dilate and become larger. As a result, fluid accumulates and causes swelling.

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. In addition, they may appear red and sensitive to light.

Photokeratitis

Photokeratitis is a painful condition that occurs when your eyes are exposed to ultraviolet (UV) rays. You can think of photokeratitis as a sunburn that affects the corneas of your eyes.

Ultraviolet rays naturally come from the sun and are also artificially produced in tanning beds. You can get photokeratitis by spending time in the sun or in a tanning bed without sun protection. It can also happen when UV rays reflect off of snow or ice and into your eyes.

In addition to redness, symptoms of photokeratitis include watery eyes, blurry vision, and light sensitivity. Symptoms typically resolve within six to 48 hours, though they may be more severe if you are exposed to UV rays for a prolonged period of time.

Pink Eye

Bloodshot eyes can be caused by pink eye, also known as conjunctivitis. Pink eye is a swelling or infection of the clear, protective layer that covers the front part of the eye.

Pink eye can be caused by allergies, bacteria, viruses, or toxic substances. It is common but usually not serious.

Pink eye is extremely contagious and can be easily transferred via touching your eyes. Avoid sharing towels or physical contact with others.

Blepharitis

Blepharitis is a common reason for painful, bloodshot eyes. It is caused by impacted oil glands that can't release the oily layer of the tear film well. This leads to inflammation of the eyelid.

Common causes include:

• Poor makeup hygiene
• Decreased blinking
• Ocular demodicosis (a skin mite that normally lives on human skin)

Blepharitis is not infectious and usually does not cause permanent damage to your eyesight. Blepharitis symptoms include:

• A sandy or burning sensation in your eyes
• Excessive tearing
• Itching
• Red and swollen eyelids
• Dry eyes
• Crusting eyelids

Uveitis

Uveitis is an inflammation of the eye's uvea, the middle layer of the eyeball. Symptoms of this condition can occur suddenly and get worse very quickly. It can cause:

• Redness
• Pain
• Blurry vision
• Floaters
• Light sensitivity

Your healthcare provider will most likely prescribe a form of steroids to help reduce swelling. If they can determine the underlying cause for the uveitis, they will treat the cause as well.

COVID and Red Eyes

Studies show that eye symptoms occur in about 5% of COVID-19 cases. When eye symptoms do occur, they often appear before other systemic symptoms, such as fever and headaches.

The most common eye symptoms associated with COVID-19 include bloodshot eyes, sensitivity to light (photophobia), soreness, and itchiness. Eye symptoms typically resolve around the same time that other symptoms do.

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 moist.

When your eye becomes dry, it also becomes red and irritated. Dry eyes can occur from:

• Staring at a computer screen for an extended amount of time
• Lack of quality sleep
• Wearing your contact lenses for too long
• Certain medications
• Hormonal changes 
• Plugged tear glands

Injury

Redness sometimes occurs with an eye injury. Injuring your eye could be as simple as sticking yourself with a mascara wand or accidentally scratching your eye with a sharp fingernail.

When you injure your eye, blood vessels inside the eye enlarge and dilate. This brings blood and cells to heal and repair the injury. A red eye from an injury is also a warning sign to tell you something is wrong with your eye.

Corneal Ulcer

A corneal ulcer occurs when the eye's cornea becomes infected, leading to a sore on the cornea. When this happens, nearby blood vessels become enlarged and swollen. As cells rush in to help fight the infection, it can cause visible redness.

With a corneal ulcer, the nearby blood vessels enlarge to quickly get important inflammatory cells to the site. In addition to bloodshot eyes, symptoms of a corneal ulcer include:

• Pain
• Discharge
• White spot on the cornea
• Blurred vision
• Itching
• Sensitivity to light

Medicated drops that are targeted to treat the cause of the underlying infection are often used to treat corneal ulcerations. The drops may be antibacterial, antiviral, or antifungal.

Steroids are not commonly started at the beginning of corneal ulcer treatment. But your healthcare provider may prescribe them to reduce scarring and inflammation once the infection is under control.

Subconjunctival Hemorrhage

A subconjunctival hemorrhage (also known as bleeding in the eye) causes the white part of the eye to become completely red. It occurs when one of the blood vessels bursts 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. Sometimes the blood can gather so much that the eye appears swollen and pouches outward.

A bleeding eye can look very scary, but it usually does not cause permanent harm to the eye and is rarely painful. Common causes include:

• Straining too hard
• Lifting something too heavy
• Sneezing or coughing too hard
• Diabetes
• High blood pressure
• Blood clotting issues
• Medications that thin the blood (e.g., aspirin, warfarin)

Acute Angle-Closure Glaucoma

Sometimes a bloodshot eye can signal a serious condition. For example, one severe eye condition that may cause red eye is acute angle-closure glaucoma.

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
• Blurred vision (usually occurring in only one eye)

Episcleritis

Another cause of bloodshot eyes 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, irritation, and eye redness. Sometimes the eyes become tender to the touch.

Scleritis is a deeper inflammation of the outer coat of the eyeball, called the sclera. In this condition, the eye is usually deep red and usually very painful.

Often, scleritis is caused by an autoimmune condition. Therefore, your healthcare provider may order blood work as part of diagnosing your condition.