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Acanthamoeba Infection of the Eye - An Overview

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Acanthamoeba is a parasitic infection of the eye that is most commonly associated with the usage of contact lenses. Read this article for more information

Medically reviewed by

Dr. Shachi Dwivedi

Published At October 13, 2022
Reviewed AtJune 7, 2023

What Is Acanthamoeba of the Eye?

Acanthamoeba is a parasitic infection of the eye caused by amoeba. Amoeba is a single-celled organism. It may be found in soil, water bodies such as lakes, oceans, tap water, swimming pools, hot tubs, and sewage systems. It is rare but more commonly seen in people who use contact lenses. This condition is serious as it may ultimately result in vision loss. A cut or abrasion on the cornea's surface can give way to the infestation by this organism.

What Are the Symptoms of Acanthamoeba Infection?

The symptoms of acanthamoeba infection (ameba in the eye) are:

  1. The blurring of vision.

  2. Cloudy appearance of the cornea.

  3. Extreme pain in the eyes.

  4. Redness of the eye.

  5. Foreign body sensation or having a feeling that something might be present in the eyes.

  6. Photophobia (sensitivity to light).

  7. Watery eyes.

  8. Presence of whitish rings on the surface of the eyes.

  9. Acanthamoeba corneal ulceration (corneal infection).

Although an acanthamoeba infection of the eye may be associated with many symptoms, two of which are characteristic of this infection. They are as follows:

  1. Pain that may be out of proportion to the clinical findings.

  2. Having a feeling that something is present in the eyes.

In the case of an acanthamoeba infection, it may be observed that the pain and other symptoms may be present even after the general course of treatment is given.

What Are the Causes of an Acanthamoeba Infection?

The causes of an acanthamoeba infection are as follows:

  1. Water - The Source: The amoeba that causes the acanthamoeba infection is known to be water-borne. Hence, one may acquire it when they come in contact with a source containing it. Sewage water or warm water tubs act as a common reservoir of amoeba.

  2. Corneal Injury: An abrasion or injury to the surface of the cornea acts as a precursor to the acanthamoeba infection. A surface injury can act as a pathway to the movement of the organism. Since this condition mainly involves the cornea, this becomes an easy way for the organism to colonize and infect.

What Is the Relationship Between Wearing of Contact Lens and Acanthamoeba Infection?

Contact lenses, when not worn properly, can lead to many adversaries. This condition is one of them. Though very rare, if left untreated, it can even lead to vision loss. Since the lens establishes direct contact with the cornea, it may directly transmit the organism to the eye layer. Infection occurs when direct contact occurs between the eye and the parasite.

How Does Acanthamoeba Infection Occur?

The process of acanthamoeba infection is as follows:

  1. When tap water or saline may be used to clean the lens.

  2. Use saline or water to store the lens.

  3. Swimming or taking a bath wearing lenses.

  4. Wearing lenses in a hot tub.

  5. Not following proper hand hygiene while handling a lens.

What Are the Complications of Acanthamoeba Infection of the Eye?

The complications of acanthamoeba eye infection are as follows:

  1. Uveitis: This condition may lead to inflammation of the various layers of the eye.

  2. Cataract: The clear lens of the eye may appear clouded.

  3. Scleritis: The sclera of the eye may become inflamed to cause scleritis.

  4. Glaucoma: Secondary damage to the optic nerve may occur. Glaucoma refers to increased intraocular pressure.

Such complications may occur with the condition as it progresses. However, if left untreated, it may ultimately result in vision loss and blindness.

How Is Acanthamoeba Infection Diagnosed?

An ophthalmologist should be able to diagnose an infection based on the symptoms along with the clinical findings noted. The doctor may suggest certain tests that may deem necessary for the patient. The test may include :

  1. Scrapings of the Cornea: It is a minor diagnostic test that involves removing scrapings from the cornea. It will be useful in studying the cells of the cornea. After numbing a small surface of the eye, the doctor may use an instrument to take superficial layers from the eye. This will be sent to the lab to study the tissue layers.

  2. Confocal Microscopy: This is used to study the various layers of the eye and also to spot the presence of parasites.

How to Stop or Treat Acanthamoeba Infection?

The treatment modalities of acanthamoeba infection are as follows:

1. Treatment of the Early Infection: Early infection involves treatment of the infection in the early stages itself. This may require only topical medications. Generally, topical antiseptic ointments will be prescribed. This may be supplemented with topical antibiotics and topical steroids.

2. Treatment of Later Stages of the Infection: Invasive infections occur in the later stages in the layers of the cornea as well as the eye. Such infections may require invasive procedures for the complete elimination of the infection. These procedures may include:

  • The doctor may do corneal scrapings up to a few millimeters and later prescribe topical medications, antiseptics, antibiotics, and topical steroids. A tablet form may also be given if the doctor may deem it necessary.

  • At times a topical treatment may not be enough, and a surgical procedure may be required. A corneal transplant may be advised by the doctor. This is a replacement procedure wherein the affected portion may be removed and replaced with healthy tissue.

How Can an Acanthamoeba Infection Be Prevented?

This is a condition with a known cause. However, the condition can be avoided by following the appropriate precautions:

  1. By not coming into contact with contaminated water or soil. As this serves as the primary source of infection.

  2. Use only disinfectant lens solution to store lenses.

  3. Not washing lenses using tap water.

  4. Following appropriate hand hygiene practices before and after the use of the lens.

  5. Not swimming or taking a bath wearing a lens.

  6. Using the lens only for the specified time period.

  7. Not using an expired lens.


Though an acanthamoeba infection of the eye is very serious, its occurrence is preventable if adequate precautions are taken. So it is better to take adequate preventive measures and stay safe. It is advisable to get your eyes checked once a year. In case of any discomfort experienced while wearing or after removing the lens, it is advisable to consult a physician immediately. If the condition is diagnosed in the early stages, the complete dosage should be completed for the thorough eradication of the disease.

Frequently Asked Questions


How Does an Acanthamoeba Infection Enter the Eye?

An acanthamoeba infection can enter the eye through any cuts or abrasions on the eye's surface. These organisms exist in contaminated water, such as puddles, swimming pools, and ponds. It can also enter the eye when contact lenses are handled with dirty hands.


What Are the Causes of Acanthamoeba?

The causes of acanthamoeba may include
- Swimming in dirty and contaminated water.
- Hot tub baths that need to be cleaned.
- Showering or swimming with contact lenses. 
- Contacting dirty water.
- Corneal injury.


How Does Acanthamoeba Keratitis Look Like?

Acanthamoeba keratitis is an amoebic infection of the eyes. This infection occurs when contaminated water comes in contact with cuts or abrasions in the cornea. This condition can present as clouding of the cornea. The cornea may appear dirty. The patient may experience blurring to loss of vision.


How Can One Prevent Acanthamoeba Infection?

The following measures, if taken, can prevent an acanthamoeba infection:
- Changing contact lenses at the prescribed intervals. 
- Placing or removing contact lenses only with clean fingers. 
- Avoid contact with contaminated water. 
- Avoid bathing with contact lenses.
- Consult a doctor in case of any cuts or abrasions in the eyes.


Can Acanthamoeba Infection Reach the Brain?

Yes, an acanthamoeba infection can reach the brain through any cuts or abrasions in the skin. Besides the corneal abrasions, this infection can travel through the nostrils or skin wounds. These organisms can travel through the bloodstream to reach the brain and spinal cord.


Can Acanthamoeba Keratitis Be Cured?

The cure for acanthamoeba depends on the stage of the disease progression. The early stages of the disease can be cured with minimal damage to the vision. Steroids are used in the treatment of acanthamoeba. The advanced stages of acanthamoeba may not have a cure. This condition can lead to vision loss if a timely diagnosis is not made.


What May Be the Symptoms of Parasites in the Eye

The symptoms of parasites in the eye can include;
- Floaters in the eyes.
- Sensitivity to light.
- The blurring of vision.
- Partial loss of vision.
- Visual disturbances.
- Redness or itching in the eyes.
In case of any visual disturbances, it is important to consult an ophthalmologist.


What Is the Healing Period for Acanthamoeba?

The healing period for acanthamoeba depends on the stage of the disease. The treatment for an early acanthamoeba infection includes topical antiseptic and steroids. These will be prescribed as ointments that must be applied to the eyes. The treatment for acanthamoeba can last between six months to one year. However, the exact duration of the treatment depends on the severity of the condition.


How Is Acanthamoeba Keratitis Diagnosed?

An ophthalmologist can diagnose an acanthamoeba infection. The diagnosis will be made based on the symptoms and a few tests. The doctor will take a scrapping from the cornea to check for the presence of the causative organism. Also, a procedure called confocal microscopy will be performed to check the organism's presence. Early diagnosis will have a better prognosis in the case of acanthamoeba keratitis.


How to Cure an Eye Infection Naturally?

An eye infection can be cured naturally in the following ways:
- Splashing fresh water onto the eyes.
- Keeping the hands clean.
- Avoid rubbing the eyes.
- Avoid the eyes from becoming dry.
However, it is always advisable to get an opinion from an ophthalmologist in case of an eye infection and receive appropriate treatment to avoid complications.


Can an Eye Infection Cause Permanent Damage to the Vision?

Yes, an eye infection, if left untreated, can cause permanent damage to the vision. Eye infections such as acanthamoeba keratitis can cause severe eye damage, ultimately leading to vision loss. Though all infections begin as blurring of vision and disturbances, they can cause severe damage if ignored. Hence the timely diagnosis of eye infections is very important.


Acanthamoeba Belongs to Which Group of Species?

Acanthamoeba is a microscopic amoebic organism. It is a single-celled organism. This species is found in soil and water. It can enter the body through contaminated water. An acanthamoeba can cause severe skin, eyes, and central nervous system infections.
Dr. Shachi Dwivedi
Dr. Shachi Dwivedi

Ophthalmology (Eye Care)


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