Definition & Overview

An eye infection is a condition that occurs when bacteria, fungi, parasites, or viruses infect the eye. Some infections affect only one eye while others affect both. There are different kinds of eye infection, which are classified depending on the causes of the condition and the specific part of the eye that has been affected.

An example of a common eye infection under the latter classification is conjunctivitis, which is also called pinkeye. Conjunctivitis is the inflammation of the conjunctiva or the membrane of the inner eyelid. It affects the white parts of the eye and the inner part of the eyelid. It is a type of infection common among children and is known to be very contagious. It is caused by the adenovirus, which is a type of common cold virus.

Another common eye infection is the stye, an infection that also affects the eyelid. It occurs when bacteria coming from the skin irritate the hair follicle of the eyelash. This causes swelling and pain in the affected area.

While some eye infections are easily treated with medications, some are contagious. In fact, they are commonly associated with other viral and sexually transmitted diseases.

Cause of Condition

The most common causes of eye infections are bacteria, fungi, or virus, and these infections can be triggered by a host of different factors. They can develop from something as simple as a small scratch on the cornea caused by organic matter getting into the eye to something more serious as a chemical irritation. Sometimes, underlying bacterial, viral, or fungal diseases also make patients more susceptible to localized eye infection; it is very easy for an infection in another part of the body to travel to the eye and cause damage.

Below are the diseases that commonly result in a serious eye infection:

  • Ocular histoplasmosis syndrome (OHS)
  • Chlamydia
  • Gonorrhea
  • Herpes simplex
  • Shingles (Herpes zoster, Varicella zoster)
  • Bacterial keratitis
  • Tuberculosis
  • Leprosy
  • Lyme disease
  • Acanthamoeba
  • Crab lice
  • Epstein-Barr virus or infectious mononucleosis
  • Mumps or measles
  • Influenza
  • Onchocerciasis (Also known as river blindness)
  • Sarcoidosis (The cause of this condition is not clear, but it may be due to an infection.)
  • Mycosis

Key Symptoms

The most common symptoms of an eye infection are the following:

  • Redness of the eye or eyelids
  • Itching
  • Swelling of the eyelids
  • Pain in the eye
  • Problems with vision (blurred or decreased vision)
  • A sensation that something is in the eye
  • Sensitivity to light
  • The eye produces yellowish, greenish, bloody, or watery discharge
  • The presence of a gray or white spot on the iris
  • Fever

In some cases such as when the infection is affecting the retina, optic nerve, or the blood vessels, it means that the damage is internal and no other symptoms occur other than a deteriorating vision or experiencing floaters or seeing tiny bubbles and dark spots. In instances like these, there is usually no pain experienced. Likewise, when other disease such as a cold causes an infection, the symptoms may not be so clear and defined. This is why it’s important to have the eyes checked regularly.

Who to See & Types of Treatments Available

When experiencing symptoms that are associated with an eye infection, it is best to go straight to an ophthalmologist, who can diagnose the condition and, from there, prescribe the correct treatment. Diagnosis usually requires a simple eye examination wherein the ophthalmologist uses a lighted device to look at the cornea and retina. In cases where there is a discharge from the eye, a sample of the discharge is examined to identify the kind of infection that is causing the problem. Since an eye infection can be a result of another disease, patients may also be tested for diseases such as chlamydia, gonorrhea, and herpes simplex.

Most kinds of eye infection can be treated with medications. Bacterial conjunctivitis can be cured with antibiotics. There are also medicinal treatments for fungal and parasitic infections. Eye infections associated with sexually transmitted diseases, such as chlamydia, syphilis, gonorrhea, crab lice, herpes simplex, hepatitis B, and thrush, can also be treated with antiviral or antibiotic medications. Some eye infections, however, may not require any form of treatment; for example, viral conjunctivitis typically improves on its own without treatment.

Eye drops, creams, and ointments are often used for less serious eye infections. These are easy to apply, but patients must be careful to follow the instructions, such as washing the hands before and after application.

There are, however, some serious eye infections that require special treatment. As an example, for the eye infection called histoplasma, the sole treatment available is laser cauterization. Histoplasma is an infection that affects the retina, but it is more difficult to detect than other infections; it causes the deterioration of the macula or the center of the retina. Laser cauterization can be performed to slow this process down.

A person suffering from an eye infection should be careful while the infection is active. This is because bacterial and viral infections can easily be passed on even through simple skin contact. Thus, precaution must always be practiced. Sharing of personal things such as makeup and towels can also be a way for the infection to be transferred.

Due to the important role that the eye plays in the body, as well as the potentially permanent damage that eye infections can cause, it is best to prevent them rather than cure them. This is why patients are advised to have their eyes checked regularly regardless of whether they have any specific concerns or not. Eye checkups are always included in routine medical checkups to encourage more people to seek regular eye care.


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