Your eyes may tear or water. You may notice a redness around the eyelids or how sunlight suddenly becomes an insufferable glare to look at. These are all signs of eye infections. Like any other part of the human body, the eye is not relieved of the danger of attacks from viruses, parasites, and bacteria.

Children are the most prone to bacterial infections, with younger ages registering longer-lasting cases of pinkeye. You’ve surely heard of the pink eye, but there are other eye infections that are more severe and long-term.

Eye Infections – Causes and Treatment

Classifying Eye Infections

First, we need to be able to identify the symptoms. Some common symptoms of conjunctivitis, keratitis, and other eye infections are:

  • Blurred or decreased vision.
  • Pain or itching in the eye.
  • Sensation of a foreign body in the eye.
  • Fever with no other cause.
  • Photophobia, or increased aversion to light.
  • Discharge of yellow, green, or bloody pus that may be crusty when you wake up in the morning.
  • A white spot on the cornea, the clear dome over the colored part of the eye.
  • Increasing redness of the eye or eyelids.

Secondly, eye doctors look at the part of the eye that’s infected.

Conjunctivitis is an inflammation of the conjunctiva, the membrane of the inner eyelid. Blepharitis attacks the eyelid, vitritisthe liquid inside the eye, keratitis – the cornea, chorioretinitis – the retina, and neuroretinitis – the optic nerve.

Thirdly, what are the causes of eye infections? Before we embark on a long list, the answer to the most widespread question out there – ‘Can I get pink eye from swimming in a pool?’ is Yes!

Conjunctivitis is a bacterial infection, but can also occur as an allergic reaction chlorine in swimming pools.

Causes of Eye Infections

Infectious conjunctivitis

This form of conjunctivitis is the most common cause of pink eye around the world. Pink eye is inflammation of conjunctiva – the clear covering of the white of the eye and the inside of the eyelids.

Anyone can get pink eye, but since it’s such a highly infectious disease, it usually spreads in tight and close communities, such as classrooms and daycare centers.

Children, preschoolers, teachers, and daycare workers are the ones mostly affected by pink eye.

Based on cause, the primary types of conjunctivitis are:

Viral conjunctivitis – This type is caused by a virus, like the common cold.

Allergic conjunctivitis – Caused by eye irritants such as dust and pollen, this form of pink eye is mostly seasonal.

Bacterial conjunctivitis – Caused by bacteria, it’s the most dangerous form of pink eye. Your eye doctor will probably have to prescribe antibiotic eye drops for its treatment.

Conjunctivitis can also affect your dog or cat. A discharge or watery fluid or yellow-green pus is a first sign your pet might have an inflammation of the eye.

Eye infections

Consider anything from allergies, birth defects, eye injuries to dry eye syndrome or even tumor as possible causes for eye infections in dogs.

  • Depending on the cause, treatment for your dog may include:
  • Antibiotics and saline washes.
  • Eye surgery.
  • Pain medication to remove any irritant from the eye.
  • Antihistamines to cure allergies.

Herpes simplex

An episode of a Herpes Simplex eye infection often clears without any permanent damage, but there are cases where the cornea is left scarred. This can eventually lead to permanent blindness.

To help prevent corneal scarring, treat the infection early on with antiviral eye drops or ointment.

Primary infection with Herpes Simplex is when you get infected for the first time. From then on, the virus takes root and, even if it remains inactive and may not appear on the surface ever again, it stays with you for life.

It is a common occurrence among children, when it is usually passed on by close contact such as kisses, for example from a family member with a cold sore or STI.

In the eye, herpes can cause ulceration and pitting of the cornea. Infection of the cornea is called keratitis.

Chronic herpes infection, which is thankfully uncommon, can cause acute retinal necrosis. About 15% of patients with ARN lose part of their vision.

At some stage in their life, most likely between the ages 30 – 40, about 2 people in 1,000 will develop at least one episode of active herpes simplex eye infection.


Before starting pouring eye drops, consult with your eye care provider. Using a procedure called debridement, he will gently scrape away the worst of the infection from the surface of the eye, while numbing it with a few anesthetic drops before.

If the deeper layer of the cornea is affected – a condition called stromal keratitis, your eye specialist will add steroid eye drops to the usual antiviral eye ointment treatment.

Chlamydia and gonorrhea

Eye infections

Chlamydia and gonorrhea are two widespread sexually transmitted diseases that can also affect the eye. They are one of the main causes of conjunctivitis, causing infection of the clear membrane that covers the white of the eye.

The infection could get into the eye when people rub their eyes after handling infected genital areas. Neisseria gonorrhea is one bacteria capable of penetrating the protective layers of the eye.

In adults, they don’t cause severe damage, but babies born to genitally infected women are at high risks of an eye infection. Any newborn with pink eye should be evaluated for chlamydial conjunctivitis, although not all instances of conjunctivitis are related to STD.


Applying silver nitrate and antibiotic ointments to the eye of newborn babies within an hour of birth has proved to be a successful measure. It is only preventive, though, and further antibiotic treatment is needed.

Sexually active adults exposed to secretions containing these infectious agents may also need antibiotic treatment.

Ocular histoplasmosis syndrome (OHS)

Eye infections

Histoplasmosis is a fungus commonly present in the river valleys around the world, with prevalence in the area known as the Bible Belt, or the Histo Belt of the United States.

The fungal spores are inhaled early in life and can cause an asymptomatic infection throughout the body, mainly the lungs.

So how does histoplasmosis cause eye infections? Scientists believe that the fungus spread from the lungs through the choroid, a layer of blood vessels with the role of providing blood and nutrients to the retina.

Only many decades later after a lung infection, do choroidal scars develop leaking of blood and fluid. Unfortunately, this is not apparent to the naked eye at once and only a dilated eye examination can reveal the leakage in the macula.

Some symptoms do occur, so you should keep an eye for any signs of loss of reading vision and distorted central vision.

Over 90% of adults in the central and eastern US test positive for exposure to histoplasmosis in skin tests. People of African descent are largely immune. Since the organisms die soon after the initial infection, ocular histoplasmosis syndrome cannot be transmitted to other people.


Corticosteroids are recommended by doctors for acute histoplasmosis inflammation. These can reduce the inflammation and ease the vision problems. Laser photocoagulation surgery is the standard treatment for choroidal neovascularization outside the macular center.


Shingles are the chickenpox virus striking twice. Herpes zoster, as known in the medical field, is caused by reactivation in the adult years of the chicken pox virus that occurred during childhood.

When the body’s immune system is weak due to stress, fatigue, chemotherapy, poor nutrition, or certain medications, it leaves ground for the virus to develop.

The sores known as shingles are infectious and can be transmitted to others. If you touch your eyes after touching a sore, it can cause ocular infection.

Shingles can lead to redness of the conjunctiva, scarring of the cornea, swelling of the eye known as iritis, and blurred vision. Herpes Zoster eye infection, in severe and repeated episodes, is associated with glaucoma and cataract.

As mentioned before, herpes simplex might be the leading cause of acute retinal necrosis in young men especially, but varicella zoster is the leading cause in people over 50 years of age.

Bacterial keratitis

Keratitis has figured on our list before, in the herpes simplex category of eye infections. Bacterial keratitis is an infection of the cornea, the clear dome over the front of the eye.

Both eye injuries and lack of oxygen due to contact lenses can be at the root of bacterial keratitis. The infection develops fairly quickly, and if left untreated, can cause permanent loss of vision.

In addition to bacterial keratitis, there are other types of keratitis:

  • Fungal keratitis – infection with fungi.
  • Amoebic keratitis – usually seen in contact lens wearers.
  • Viral keratitis – caused by herpes simplex or shingles.
  • Photo keratitis – caused by intense radiation exposure.


A few visits to the eye specialist and antibiotic drops should do the trick. Your doctor may also recommend you apply some steroid drops to the eye.

Here’s a list of other infections that can cause conjunctivitis or keratitis are:

  • Tuberculosis, leprosy, or Lyme disease.
  • Influenza, mumps, and measles.
  • Acanthamoeba, a common parasite or crab lice.
  • Infectious mononucleosis.
  • Candida, or mycosis.

Broad-spectrum antibiotics will deal with most cases of eye infections, while particular measures and a definite visit to the eye specialist must be taken to ensure your eyesight won’t be scarred for life.

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