Acanthamoeba Infection of the Eye - An Overview

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:

• The blurring of vision.

• Cloudy appearance of the cornea.

• Extreme pain in the eyes.

• Redness of the eye.

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

• Photophobia (sensitivity to light).

• Watery eyes.

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

• 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:

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

• 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:

• 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.

• 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:

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

• Use saline or water to store the lens.

• Swimming or taking a bath wearing lenses.

• Wearing lenses in a hot tub.

• 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:

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

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

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

• 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 be deemed necessary for the patient. The test may include :

• 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 for study of the tissue layers.

• 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?

Eliminating the infection and lowering pain and other bothersome symptoms are the two main objectives of treating AK. The first line of treatment is typically medication; in more serious cases, surgery might be required. 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 to completely eliminate them. 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 deems 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.

• Specific tissue transplants, such as amniotic membranes, can support the healing process of the eye.

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:

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

• Only disinfectant lens solution is used to store lenses.

• Not washing lenses using tap water.

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

• Not swimming or taking a bath wearing a lens.

• The lens is used only for the specified period.

• Not using an expired lens.

How Can Individuals Determine Whether Amoeba Is in Their Eye?

They cannot determine whether they have amoeba-related infections, such as AK, on their own. It is only detectable by specific medical tests. For a medical evaluation and treatment, one should consult an eye care professional.

What Is the Prognosis of Acanthamoeba Infection of the Eye?

AK is a disorder that can be extremely painful and disruptive. It is critical to adhere to the doctor's treatment recommendations exactly as prescribed. That maximizes the chances of a successful outcome. If individuals fail to follow the instructions given by the doctor, they are at risk of getting infected again. If left untreated for too long, AK can result in serious, irreversible damage. The potential side effects include glaucoma, cataracts, iris atrophy (shrinking or shifting out of place), and persistent flaws in the outermost layer of the cornea. Significant vision loss may occur in more extreme situations.

Conclusion:

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 the 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.