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5 Common Types of Eye Infections: Symptoms, Causes, and Treatments

Written by Andrew Le, MD

UpdatedFebruary 29, 2024

Eye infections are common and affect a significant proportion of the American population, with an estimated one million individuals suffering from these infections annually. These infections can impact various eye parts, including the cornea, conjunctiva, and eyelids.

Dealing with eye infections can cause discomfort and itchiness, which can be bothersome. While some minor eye infections can heal on their own, others can be serious and may cause permanent vision loss.

In this article, you will learn the five common types of eye infections, exploring their symptoms, causes, effective treatments, and tips for preventing them.

🔑 Key Takeaways

  • Eye infections are common and can impact various eye parts, including the cornea, conjunctiva, and eyelids.
  • Harmful microorganisms like bacteria or fungi can cause eye infections resulting from poor hygiene, contact with contaminated objects or surfaces, or certain medical conditions.
  • The types of eye infections include viral conjunctivitis, bacterial conjunctivitis, fungal endophthalmitis, keratitis, and parasitic eye infections like river blindness, crab lice, and acanthamoebiasis.
  • Symptoms of an eye infection may involve redness, swelling, discharge, itching, and discomfort in the eyes.
  • Conjunctivitis, or pink eye, is a medical condition characterized by inflammation of the conjunctiva. It can result from various causes, including viral or bacterial infections and allergic reactions.
  • Treatment options for conjunctivitis include home remedies, such as applying a cool, wet washcloth on the eyes, using certain eye drops for itchiness and puffiness in allergic conjunctivitis, and rinsing the eye if a chemical or foreign substance causes conjunctivitis.
  • Medical interventions may be necessary if the symptoms are more severe or do not improve within a few days.
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What Is An Eye Infection?

An eye infection is a condition that occurs when harmful microorganisms such as bacteria or fungi enter the eye and cause inflammation or damage to the eye tissues. Eye infections are common among children, with up to 1 in 8 children experiencing such infections each year.

Symptoms of an eye infection can differ based on the type of infection. However, some general symptoms may include:

  • Redness
  • Swelling
  • Discharge
  • Itching
  • Eye discomfort

What Causes Eye Infections?

Various factors, including poor hygiene, contact with contaminated objects or surfaces, or certain medical conditions, can cause eye infections. Below are the common causes of eye infections:

  • Viruses: Infective agents that duplicate themselves within a living host, causing viral eye infections such as viral conjunctivitis and ocular herpes.
  • Bacteria: Single-celled organisms that enter the eye, thrive, and multiply through binary fission, leading to bacterial eye infections like bacterial keratitis and conjunctivitis.
  • Parasites: Small creatures that live within the eye, causing parasitic eye infections like river blindness, crab lice, and acanthamoebiasis.
  • Fungi: Rare but serious conditions that occur most frequently when an injury leaves plant material in the eye, resulting in fungal eye infections like fungal endophthalmitis and keratitis.

What Are The Types Of Eye Infections?

The symptoms and severity of eye infections can vary depending on the type of infection. In general, it is essential to recognize the type of infection as it can help determine the appropriate treatment. Below are five common types of eye infections:

1. Conjunctivitis (Pink Eye)

Conjunctivitis, often known as pink eye, is a medical condition marked by inflammation of the conjunctiva. In the US, around 6 million cases of pink eye are reported annually. The conjunctiva is a delicate, see-through membrane that wraps around the eye's white part and lines the eyelids' inner surface. Pink eye can result from various causes, including viral or bacterial infections and allergic reactions.


The symptoms of conjunctivitis may include:

  • Red and swollen eyes
  • Watery eyes with a clear or thick discharge
  • Itchy eyes
  • Burning sensation in the eyes.
  • Gritty sensation, as if there's something in the eye
  • Painful eyes, especially in bacterial conjunctivitis
  • Puffy eyelids
  • Blurry or hazy vision
  • Sensitivity to light


Below are common causes of conjunctivitis, such as:

  • Viral Conjunctivitis: Viral conjunctivitis is the most prevalent form of conjunctivitis, known for its high contagion potential, especially in crowded environments. This type of conjunctivitis is responsible for most infectious conjunctivitis cases, accounting for up to 75% of all reported cases.
  • Bacterial Conjunctivitis: Bacterial Conjunctivitis is an extremely contagious eye infection resulting from bacterial infections. Soreness, red eyes, and sticky pus discharge characterize it. In the US, the incidence rate of bacterial conjunctivitis is 23,000 per 100,000 cases.
  • Allergic Conjunctivitis: Allergic conjunctivitis is a condition produced by an allergic reaction to substances such as pollen, animals, smoke, or environmental factors. According to a study of 20,010 patients, the prevalence of allergic conjunctivitis is 6.4%, and 29.7% reported experiencing the condition.

🩹Health Note:

Allergic conjunctivitis is not contagious, unlike infectious conjunctivitis. Allergic conjunctivitis is caused by exposure to allergens, while viruses, bacteria, or other microorganisms cause infectious forms of conjunctivitis.

Treatment Options

Treatment options for conjunctivitis vary based on the underlying cause and severity of the condition. These remedies include:

1. Home Remedies

Home remedies can effectively relieve mild symptoms and prevent the spread of infection. Self-care measures to alleviate symptoms include:

  • Apply a cool, wet washcloth on the eyes for comfort.
  • Using certain eye drops for itchiness and puffiness in allergic conjunctivitis.
  • Rinsing the eye if a chemical or foreign substance causes conjunctivitis.
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🩹Health Note:

Viral conjunctivitis often resolves independently without specific treatment.

2. Medical Interventions

If your symptoms are more severe or do not improve within a few days, you may need medical intervention. Your doctor may prescribe:

  • Antibiotic Eye Drops: Prescribed for bacterial conjunctivitis to combat bacterial infections.
  • Allergy Medications: For allergic conjunctivitis, medications are used to manage allergic reactions.
  • Consultation with an Ophthalmologist: Especially if symptoms persist for more than 1–2 weeks or if a more serious eye problem is suspected.
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2. Stye (Hordeolum)

A stye, or hordeolum, is an infection that affects an oil gland at the eyelid's edge. A bacterial staph infection commonly causes this infection and is more frequently seen in children than adults.

As a result of this infection, a lump or pimple filled with pus appears at the eyelid's edge, leading to swelling, pain, and redness. Styes can be identified easily based on appearance and location, usually on eyelids.


Patients with a stye commonly present with the following symptoms:

  • Eyelid swelling, redness, pain, or tenderness.
  • A sensation of having something in the eye.
  • Excessive tearing.
  • Crusting of the eyelid.


The primary cause of a stye is an acute bacterial infection of the eyelid margin. Staphylococcus aureus is responsible for 90% to 95% of cases, with Staphylococcus epidermidis being the second most common cause.

Additionally, certain factors and conditions may contribute to the development of a stye, including:

  • Contact lens wear.
  • Poor hygiene.
  • Use of old or contaminated eye makeup.
  • Blepharitis (inflammation or infection of the eyelids).
  • Systemic conditions such as rosacea, seborrheic dermatitis, or diabetes.

Treatment options

When addressing a stye infection, several treatment options can help ease symptoms and expedite the recovery process, including:

1. Warm Compresses

Using compresses on the affected eye can aid in a faster recovery and prevent the spread of infection. Applying the compresses for at least 15 minutes four times a day is recommended. The warmth from the compress aids in alleviating pain, encouraging drainage, and improving blood circulation in the affected area.

2. Antibiotics

Antibiotic treatment is used to manage bacterial infections, typically with erythromycin ophthalmic ointment applied twice daily for 7 to 10 days.

❗Remember :

Topical antibiotics are frequently prescribed for skin conditions and infections, but there is insufficient evidence to support their effectiveness and safety. Seeking advice from a medical professional before using topical antibiotics is recommended to evaluate potential risks and benefits.

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3. Blepharitis

Blepharitis is a medical condition that refers to the inflammation of the eyelids. It is characterized by redness, irritation, and itchiness. In addition, it often involves the formation of dandruff-like scales on the eyelashes.

A US ophthalmologists and optometrists survey revealed that 37% to 47% of the patients they examined showed signs of blepharitis. This common eye disorder can be caused by either bacteria or skin conditions such as scalp dandruff or rosacea.

Blepharitis comes in two primary forms: anterior and posterior.

  • Anterior Blepharitis: This type shows up on the outer edge of the eyelid where the eyelashes are situated. It is frequently caused by bacteria (staphylococcal blepharitis) or dandruff from the scalp and eyebrows (seborrheic blepharitis).
  • Posterior Blepharitis: Affects the inner edge of the eyelid that touches the eyeball. It can occur due to irregular oil production in the eyelid glands (meibomian blepharitis) or other skin conditions like rosacea and scalp dandruff.


People with blepharitis may experience various symptoms, including:

  • Feeling like there's something in your eye
  • Burning or stinging eyes
  • Watery eyes
  • Itchy eyes
  • Sensitivity to light
  • Red and swollen eyes or eyelids
  • Foamy or bubbly tears
  • Dry eyes
  • Crusty eyelids or eyelashes upon waking up


The primary cause of blepharitis is an excess of bacteria on the eyelids, especially at the base of the eyelashes. Factors contributing to blepharitis include:

  • Too much bacteria on the eyelids
  • Blocked or irritated oil glands in the eyelids
  • Conditions such as dandruff, rosacea, oily skin, and allergies affecting the eyelashes

Treatment options

Maintaining good hygiene of your eyelids is important to prevent infections and other eye-related issues. To effectively manage the symptoms of Blepharitis, there are several treatment options available, such as:

1. Eyelid Hygiene

To keep your eyelids clean, you can:

  • Regularly clean your eyelids to remove crusts and maintain hygiene.
  • Use a gentle cleanser (e.g., baby shampoo) mixed with warm water.
  • Apply a clean, soft cloth or cotton swab to the eyelids, focusing on the base of the eyelashes.
  • Rinse eyes with clean water.
2. Medications

Medications can be used to treat eye conditions, such as:

  • Eye Drops: Steroid eye drops might be prescribed to manage redness, swelling, and irritation. Artificial tears can also be recommended for lubrication.
  • Antibiotics: If blepharitis is caused by bacteria, antibiotic eye drops, ointments, or pills might be prescribed.
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4. Keratitis

Keratitis is the inflammation of the cornea, marked by swelling, infiltration of inflammatory cells, and ciliary congestion. This condition can result from exposure to infectious agents or self-antigens, affecting corneal layers.

The inflammatory response may lead to suppurative melting of the corneal epithelium and stroma, potentially causing ulcers and threatening the eye's integrity. If left untreated, bacterial keratitis can lead to vision loss and, in severe cases, blindness.

According to the CDC, an estimated 930,000 visits were made to doctors' offices and outpatient clinics, and 58,000 emergency department visits were made for keratitis. It is also estimated that 25,000 individuals in the US develop bacterial keratitis yearly.


Symptoms of keratitis may manifest suddenly and include:


The causes of bacterial keratitis are:

  • Contact Lens Use: Extended-wear lenses or improper care and maintenance of contact lenses increase the risk of bacterial keratitis. Wearing lenses for extended periods or failing to clean them properly can lead to corneal infections.
  • Eye Injury: Trauma to the eye can also result in bacterial keratitis. Prompt care and attention to eye injuries are essential to minimize the risk of infection.

Treatment options

Prompt and appropriate treatment is vital to prevent complications and preserve vision. Treatment for bacterial keratitis may include:

  • Antibiotic Eye Drops: Bacterial keratitis is typically treated with antibiotic eye drops. These drops are administered frequently to eliminate the infection.
  • Steroid Drops: In some cases, steroid eye drops may be used with antibiotics to reduce inflammation and promote healing.

In severe instances where keratitis results in substantial corneal damage, a corneal transplant may be contemplated. This surgical intervention entails replacing the impaired cornea with a healthy donor cornea to regain vision.

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5. Uveitis

Uveitis is a condition marked by inflammation within the eye. This inflammation can result from the immune system responding to an infection in the eye or attacking healthy eye tissues. Uveitis primarily affects the uvea, which is located in the middle layer of the eye and includes the iris, ciliary body, and choroid.

The prevalence of noninfectious uveitis in the US is estimated to be 121 cases per 100,000 persons. The study also found that women had a higher prevalence of uveitis than men, with 146 cases per 100,000 women and 119 cases per 100,000 men.

Another study reported a prevalence of uveitis of 5.4/1000 in the US adult population within an age range of 20 to 69 years old.


Uveitis can manifest suddenly, and its symptoms may include:

  • Redness of the eye with or without pain
  • Increased sensitivity to bright light
  • Blurry vision
  • The sudden occurrence of "floaters," which are specks or drifting clouds in the field of vision.


Uveitis can be caused by autoimmune diseases, including:

  • AIDS
  • Ankylosing spondylitis
  • Behcet’s disease
  • Lupus
  • Multiple sclerosis
  • Psoriasis
  • Rheumatoid arthritis
  • Sarcoidosis
  • Ulcerative colitis
  • Vogt-Koyanagi-Harada (VKH) disease

Infections and related conditions that can cause uveitis:

  • Cytomegalovirus (CMV) retinitis
  • Histoplasmosis
  • Reactive arthritis
  • Shingles
  • Syphilis
  • Toxoplasmosis

Uveitis can also be associated with eye-affecting cancers such as lymphoma.

Treatment options

Treatment options for Uveitis include the use of:

1. Corticosteroids:

Steroids are commonly used to reduce inflammation in the eye. Administration methods include:

  • Eye drops (most common)
  • Pills
  • Injections around the eye
  • Implants (small devices placed in the eye for gradual steroid release)


It's important to note that steroid use may have side effects, including an increased risk of cataracts and glaucoma. Regular eye examinations are advised to keep track of these potential issues.

2. Immunomodulatory Drugs:

Immunomodulatory drugs may be prescribed in certain cases to manage the immune system. These drugs alter or regulate the immune response to prevent additional inflammation and tissue damage. Customized treatment plans are tailored to factors such as the affected area of the eye and other underlying health conditions.

How To Prevent Eye Infections?

To avoid such eye infections, it's important to take certain precautions. Here are some tips that can help prevent eye infections:

  • Wash Your Hands: Frequent hand washing is a simple and effective defense against microbes that can cause eye infections.
  • Avoid Rubbing Your Eyes: If your eyes water, itch, or have any liquid discharge, avoid rubbing them with your hands. Use a soft washcloth to clean your eyes instead of your hands. Rubbing your eyes with contaminated hands can spread infections.
  • Clean Contact Lenses: Take proper care of your contact lenses to prevent them from becoming coated with bacteria, viruses, or parasites. Follow basic steps for cleaning your contact lenses regularly.
  • Clean Contact Lens Case: Keep your contact lens case clean by replacing it every three months. Never top off an old solution in the case; use a completely new, store-bought solution every time.
  • Launder Linens and Clothing: If you have an eye infection, launder linens, bedding, or clothing that might have touched your eyes. This aids in avoiding the transmission of the virus to family, friends, and co-workers.
  • Seek Professional Help: If you experience symptoms such as red, itchy, watery eyes, mucous drainage, or eyelids and lashes sticking, consult an ophthalmologist. Ophthalmologists can help diagnose and treat various eye problems, including infections.
  • Replace Your Contact Lens Case: Consistently replace your contact lens case every three months to avoid the accumulation of contaminants.
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Effectively treating eye infections like uveitis is crucial for preventing additional damage and complications. Treatment options may involve the use of corticosteroids and immunomodulatory drugs, among others.

However, it's important to note that some treatments may have side effects and regular eye exams are recommended to monitor for potential issues.

To prevent eye infections, certain precautions such as frequent hand washing, avoiding rubbing your eyes, and maintaining proper contact lens hygiene are important. Early intervention by seeking professional assistance at the first signs of symptoms can facilitate the effective diagnosis and treatment of eye issues.

FAQs On Eye Infections

What is the quickest method to treat an eye infection?

Saltwater, also known as saline, is a highly effective natural remedy for treating eye infections at home. Saline is very similar in composition to teardrops, which is the natural way your eyes cleanse themselves. Salt also has antimicrobial properties, making it a logical choice for treating eye infections. Therefore, using saline solution can be an effective treatment for eye infections.

How can I determine if my eye infection is a serious condition?

Severe symptoms such as extreme pain, severe light sensitivity, or sudden loss of vision require emergency medical care. Similarly, if symptoms of blepharitis, conjunctivitis, or a stye do not improve with home care, seek medical attention.

How long do eye infections last?

An eye infection's duration depends on the infection type, severity, and treatment. Bacterial and viral infections can last from a few days to a few weeks. Fungal infections may take longer to clear up and require more intensive treatment.

Are eye infections contagious?

Yes, many eye infections are contagious. Eye infections, particularly bacterial and viral, can be transmitted through contact with an infected person's tears or nasal discharge. Good hygiene and not touching your eyes are vital to prevent transmission. Avoid close contact if you have an eye infection until it clears up.