Eye infections occur when some harmful organism invades an area of your eye. (Learn More)

The source of the infection is often bacterial or viral, but it may be due to some other cause. (Learn More) Treatment depends on the cause of the infection. (Learn more)

Despite the cause, the symptoms that occur when you have an eye infection are typically similar. (Learn More) If you suspect you have an eye infection, have your physician evaluate the problem. (Learn More)

There can be numerous types of eye infections that can include conjunctivitis, (Learn More) keratitis, (Learn More) acanthamoeba keratitis, (Learn More) blepharitis, (Learn More), uveitis,  (Learn More) cellulitis, (Learn More) ocular herpes, (Learn More) endophthalmitis, (Learn More) chlamydia trachomatis, (Learn More) a sty, (Learn More) dacryostenosis (Learn More) corneal ulcers, (Learn More) and orbital cellulitis. (Learn More)

When it comes to dealing with potential eye infections, prevention is the best cure. (Learn More)

itchy eyes

Eye Infections

An eye infection occurs when a potentially harmful microorganism like a fungus, a virus, or bacteria invade your eyeball or the area surrounding your eye.

The infection can affect the eyeball, the clear surface of the eye (cornea), or the eyelids.

Bacterial vs. Viral Infection

Bacterial infections and viral infections of the eye may often produce similar symptoms. They may even spread in a similar manner, but they are two different infections that will often require different treatment approaches.

Bacterium consists of single cells that can survive on their own. They are complex organisms within a single cell, and most of them are not harmful.

Viruses are smaller than bacteria, and they are not single cellular mechanisms. A virus is made up of a center core of genetic material, which can be DNA or RNA that is surrounded by a capsid, a protective coat made of protein. Sometimes the capsid is surrounded by a spiky covering that is called an envelope.

Viruses cannot survive on their own. They need some type of a host, and they will attach to host cells and invade them.

eye doctor examining woman's eye

Treatment for Eye Infections

Obviously, bacteria cause bacterial infections, and viruses cause different viral infections. The treatments differ depending on whether you have a bacterial or viral infection.

Bacterial infections are often treated with antibiotics, which can kill the bacteria or stop it from multiplying. Antibiotics will not work for viral infections.

Instead, the symptoms of the virus are usually treated directly. There are some antiviral medicines that can stop the virus from reproducing. Certain vaccines can prevent viral infections from occurring in the first place, such as the vaccine for influenza.

Many of the common bacterial infections of the eye will readily clear up once you are prescribed an antibiotic or some other treatment like eye drops. Some of the more common viral eye infections may resolve on their own, but they may require antiviral eye drops or even steroids to reduce inflammation.

Symptoms of an Eye Infection

The symptoms of an eye infection can be variable, depending on the cause of infection. Most commonly, the symptoms include one or more of the following:

  • Red eyes or watery eyes
  • Discharge from the eyes
  • Pain in the eyes
  • Dry eyes
  • Swelling around the eyes or in the eye
  • Itching
  • Sensitivity to light or blurry vision

Woman with glasses suffering from eyestrain after long hours working on computer

What Should I Do if I Think I Might Have an Eye Infection?

If you suspect you might have an eye infection, visit your eye doctor. Don’t try to diagnose the condition yourself.

If you wear contacts, should stop using them. Only wear your glasses until you discuss the situation with your doctor.

Your doctor will need to determine what the cause of your eye infection is before treatment can be implemented. This may require a sample from your eye or some other procedure. Your physician may be able to tell just by looking at you, assessing your symptoms, and then formulating the most likely cause of your infection.

According to the book Essentials of Ophthalmology and a 2018 article in the journal The Australian Prescriber, there are numerous different types of eye infections.

Conjunctivitis

Conjunctivitis, commonly called pink eye, is a highly contagious and common eye infection. It can spread in environments where there are many people working together closely. It is a common eye infection that spreads in schools among small children.

Conjunctivitis can have viral or bacterial origins. Most often, the infection will go away, but treatments can speed up the process. Any bacterial conjunctivitis can be treated with antibiotic eye drops, and conjunctivitis due to allergies can be treated with antihistamines.

There is no treatment for conjunctivitis caused by a viral infection, but you can soothe the discomfort by placing a wet cloth on your eyes.

With any eye infection, you should wash your hands frequently, and avoid touching your eyes.

Keratitis

Keratitis occurs when the cornea gets infected. It can be a bacterial infection, a viral infection, a fungal infection, or a parasitic infection (see below).

Depending on the cause of the infection, antibacterial eye drops, antifungal eye drops, or antiviral medications or eye drops may address it.

Acanthamoeba Keratitis

Acanthamoeba keratitis is a rare disease that may occur when amoebae invade the cornea of the eye. People who wear contacts should follow their safety precautions and avoid swimming with their contacts in to reduce the risk of this.

The amoeba can cause an infection of the eye that can lead to visual impairment or even blindness.

Blepharitis

Blepharitis, or inflammation of the eyelids, is often caused by the oil glands inside the eyelids getting clogged up or infected with bacteria.

It can be addressed by cleaning the eyelids with sanitary towels, using corticosteroids to treat inflammation, and using eye drops or ointments that moisten the eyes or contain antibiotics.

Uveitis

The uvea is the middle layer of your eyeball that is responsible for delivering blood to the retina, the part of the eye that sends images to your brain. Thus, it is a very important structure to keep healthy in order for you to be able to see.

Uveitis occurs when the uvea is infected. This infection can result in vision loss if not treated.

You may be required to wear dark glasses, and take corticosteroids, antibiotics, and other medications if the infection is severe.

Cellulitis

Cellulitis occurs when tissues become infected as a result of a scratch or some other injury. It can be the result of bacterial infections like a staph infection (Staphylococcus).

Treatment may consist of applying warm, damp towels to the eyes and using antibiotics or other medications.

Ocular Herpes

Exposure to the herpes virus can lead to ocular herpes (the herpes simplex type I virus), which can lead to inflammation and scarring of the cornea.

Endophthalmitis

A bacterial infection can occur in the interior of the eye as a result of some type of penetrating injury to the eye or as a complication of surgery in rare cases. Bacterial endophthalmitis can be the result of mold penetrating the interior of the eye or some other issue.

If not treated with antibiotics, blindness can result.

Chlamydia Trachomatis

The Chlamydia trachomatis bacteria can infect the eye, leading to trachoma. Trachoma is rare in the United States, but it can occur as a result of being in an unsanitary environment.

The bacteria will typically infect the inner eyelid. Eventually, this can lead to scarring of the cornea and potentially permanent blindness.

Sty

A sty may result from an infection of the interior, upper, or lower eyelid. It often resembles a pimple that has developed in an oil gland on your eyelid.

The sty may be treated with simple mild soap. Swelling can be addressed with over-the-counter medications.

Dacryostenosis

Dacryostenosis, or a blocked tear duct, can occur as a result of an infection in the tear glands.

Corneal Ulcers

An abscess or ulcer may result from an infection of the cornea, which can lead to severe vision loss.

Orbital Cellulitis

Orbital cellulitis may result from an infection of the soft tissue of the eyelids. This can spread if not treated promptly.

red eye vs non red

Prevention of Eye Infections

As is the case with many types of infections, prevention is the best form of cure. If you notice that someone has red swollen eyes, you can avoid catching whatever they have by minimizing contact with the person and using good hygiene practices.

Good hygiene goes a long way. If you wear contacts, you should always wash your hands before touching them. Do not share items that will touch your eyeball with other people. Sleeping with contact lenses in increases the risk for eye inflections, even if they are approved for overnight wear.

Always keep the towels in your bathroom clean, and change your bedding weekly. This reduces the likelihood of bacteria that can lead to eye infections.

References

Eye Disorders. (2019). Merrick Manual: Professional Version.

Bacterial vs. Viral Infections: The Differences Explained. (April 2019). WebMD.

8 Common Eye Infections and How to Treat Them. (October 2018). Healthline.

Essentials of Ophthalmology. (2019). Medical Publishers Pvt. Limited.

Common Eye Infections. (June 2018). The Australian Prescriber.