Internal Eye Infections

Dr. Russel Lazarus, June 23, 2020

Here is a guide to the most common internal eye infections, their symptoms, and treatment methods.

Eye infections can be quite uncomfortable, causing redness, pain, and inflammation.

If you are experiencing any eye pain or vision problems, schedule an eye exam as soon as possible.

If you think you may have an eye infection, schedule an eye exam as soon as possible to catch the infection in its early stages— many eye infections can lead to permanent vision loss if not treated effectively.

1. Ocular herpes

Ocular herpes, most commonly called eye herpes, develops when the eye is infected by the herpes simplex virus (HSV-1). Sometimes referred to as a ‘cold sore on the eye’, this condition is a common, recurring viral infection that causes inflammation and, if left untreated, can cause permanent scarring of the cornea

Eye herpes is highly contagious and can be transmitted through close contact with someone who has an active virus, or through self contact and contamination from a cold sore on the lip.

The National Eye Institute (NEI) estimates:

  •  400,000 Americans have had some form of eye herpes.
  •  50,000 new and recurring cases occur each year.

Eye herpes can range in severity from mild to sight-threatening, depending on the type:

1. Herpes keratitis:

This is the most common form of eye herpes, caused by a viral corneal infection. This type of ocular herpes usually affects only the top layer (epithelium) of the cornea, and generally heals without scarring.

2. Stromal keratitis:

This form results as the infection spreads deeper into the cornea. This type of eye herpes can lead to scarring, and partial or total vision loss. According to NEI, about 25 percent of new and recurring cases of herpes eye infections result in stromal keratitis.

3. Iridocyclitis:

This is a severe form of eye herpes that results from inflammation of the iris and surrounding tissues inside the eye.  Iridocyclitis is a type of uveitis that affects the frontal part of the eye. When the infection develops in the retina or the inside lining of the back of the eye, it is known as herpes retinitis.

Symptoms of ocular herpes 

  • Eye sores
  • Redness
  • Irritation
  • Swelling
  • Tearing
  • Foreign body sensation
  • Watery discharge
  • Light sensitivity
  • Recurrent eye infections

In some cases, inflammation of the cornea will cause irritation, or a sudden and severe pain in the eye, and cloudy or blurry vision.

Symptoms typically present in one eye, though eye herpes can sometimes affect the other eye as well.

Risk factors 

While the exact cause of an eye herpes infection remains unknown, the following factors have been shown to lead to an increased risk.

  • Fever
  • Trauma
  • Surgical or dental procedures

Additionally, according to the NEI:

Eye herpes has about a 50 percent chance of recurring— from several weeks or several years following the initial infection. 


There is currently no cure for eye herpes.

In most cases, eye herpes will heal on its own in a week or two, but if symptoms persist, there are treatments that can control the infection.

If the corneal infection is only superficial, your eye doctor will prescribe an antiviral medication in the form of an eye drop, ointment, or oral medication.

If the infection has spread into the deeper layers of the cornea, corticosteroid eye drops will be prescribed to reduce inflammation and prevent corneal scarring. These drops are typically used in combination with antiviral drops.

Depending on your specific case, your eye doctor may debride, or brush off, your cornea with a cotton bud to eliminate infected cells.

In rare cases when corneal scarring occurs and steroid treatments prove to be ineffective, a corneal transplant may be required to restore vision.

If you experience eye pain or vision loss, contact an eye doctor near you, who can diagnose and treat the condition.

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2. Uveitis

Uveitis is an inflammation of the uvea, the central layer of the eyeball— caused by an eye infection. The uvea is responsible for transporting blood to the retina, which is responsible for transmitting images to the brain.

Uveitis most commonly results from immune system conditions, viral infections or eye injuries.

In most cases, uveitis doesn’t cause any long-term effects, but vision loss can occur if severe cases are left untreated. 

  • Uveitis affects approximately 1 in 4500 people.
  • Uveitis is most common between the ages 20 to 60. 
  • In western countries, anterior uveitis accounts for up to 90% of uveitis cases.


  • Redness
  • Pain
  • Blurry vision
  • Light sensitivity
  • “Floaters” in visual field


In most cases, uveitis is treated with eye drops or eye injections to relieve pain and inflammation. If the infection has spread beyond the eye, oral antibiotics will be prescribed as well. In severe cases, medications to subdue the immune system will be recommended as well.

Uveitis typically improves after a few days of treatment and normal vision should return.

If you have any concerns about your vision, don’t hesitate to contact your eye doctor.

3. Periorbital cellulitis

Periorbital cellulitis, also known as eyelid cellulitis, develops when eye tissues become infected.

Cellulitis is most commonly caused by an injury such as a scratch— which creates a warm invitation to infectious bacteria, such as Staphylococcus (staph).

Cellulitis can also result from a bacterial sinus infection, or infection of another nearby structure. Cellulitis is most common among the pediatric population.


  • Eyelid redness
  • Eyelid swelling

Cellulitis does not usually cause any eye pain or discomfort.


Your eye doctor will usually prescribe an oral antibiotic such as amoxicillin, to treat the bacterial infection. In rare cases, if the infection progresses in severity, surgery will be indicated to relieve the pressure within the eye.

In the meantime, to reduce swelling, doctors recommend applying a warm compress to your eye for 20 minutes, a few times a day.

4. Endophthalmitis

Endophthalmitis is severe inflammation of the inside of your eye caused by a bacterial or fungal infection. Candida fungal infections are the most common cause of endophthalmitis. However, this type of infection can also develop after an eye injury, or more specifically, when the eye is penetrated by an object.

In rare cases, endophthalmitis can develop after certain eye surgeries, such as cataract surgery.


  • Redness
  • Swelling
  • Eye pain
  • Discharge
  • Blurry vision
  • Light sensitivity
  • Partial or complete vision loss


If the infection is caused by an eye penetration, seek emergency medical care.

The object will need to be removed by a trained professional— never try to remove a foreign object from your eye by yourself.

Infections caused by bacteria or fungi will typically be treated with antibiotic injections. The medication is injected into the eye with a special thin needle to treat the infection. Many times, a corticosteroid injection will be given as well, to reduce inflammation.  After proper care, symptoms should subside within a few days. 

When to see your doctor

If you are experiencing any eye pain or vision problems, schedule an eye exam as soon as possible.

It is important to treat eye infections as early as possible to ensure optimal treatment results and reduce the risk of complications.

LEARN MORE:  Guide to Eye Conditions

If you experience any sudden ocular pain or vision changes, seek immediate medical care.