Can You Get a Parasite in Your Eye?

Since the eyes are exposed to the environment and surroundings most of the day, they are susceptible to a parasitic infection.

3 Types of Eye Parasites

These include Toxoplasma gondii which causes toxoplasmosis, acanthamoeba which causes keratitis, and Demodex folliculorum which causes blepharitis.

Eye Parasitic Infection by Toxoplasma gondii

Toxoplasmosis is caused by a protozoan that is an obligate intracellular parasite, meaning it must live within a host cell to survive.

This parasite can be acquired by breathing it in from used cat litter boxes or by eating undercooked meat which contained the parasite.

Toxoplasma can also be transmitted from mother to child during pregnancy if the mother is exposed while pregnant.

Toxoplasmosis Symptoms and Treatments

Toxoplasmosis, which is the condition caused by the parasite toxoplasma, affects the back of the eyes primarily.

The main symptoms are inflammation of the retina and vitreous which causes hazy vision, it may also cause large floaters, and cause a red eye with light sensitivity.

The more severe and less common symptoms include convulsions and brain damage.

Toxoplasmosis is treated by preventing the parasite from replicating within the cells and managing the symptoms until the parasite is fought off by the immune system.

Eye Parasitic Infection by Acanthamoeba

Acanthamoeba is a parasitic protozoan which is found in water and soil. It is often associated with contact lens wear while swimming or rinsing contact lenses with tap water.

Acanthamoeba infection causes severe corneal inflammation known as keratitis.

Acanthamoeba Symptoms and Treatments

An infection due to acanthamoeba is marked by severe pain early in the infection, as well as a red eye and somewhat blurry vision.

A keratitis caused by acanthamoeba is treated using topical eye drops to kill the parasite and will often also require eye drops to help the cornea heal.

In some cases, pain medication or a topical numbing eye drop may be used to improve comfort until the condition heals or the pain subsides.

Eye Parasitic Infection by Demodex folliculorum

Demodex folliculorum is a mite that is found at the base of the eyelashes on the eyelid. These mites live within the hair follicles of the eyelashes.

Demodex mites are very common and do not always cause issues but can cause several conditions, namely blepharitis.

Blepharitis is the inflammation of the eyelids and eyelashes.

Demodex Symptoms and Treatments

The blepharitis caused by Demodex often results in very red eyelids, lots of debris or crusty material along the base of the eyelashes, and irritated or itching eyes.

These symptoms are not specific to Demodex, and to determine if Demodex is the cause of the blepharitis, a lash may be pulled and inspected for the presence of a mite on the base of the lash.

To treat a Demodex infection, tea tree oil or a cleanser containing tea tree oil must be used to kill the parasites.

In addition to getting rid of the mites, it is important to continue with an eyelid hygiene routine to prevent recurrence.

Prevention of Eye Parasitic Infections

All of the parasitic infections above can be prevented with some basic preventative eye care.

In order to reduce to risk of toxoplasmosis, if you are pregnant, do not change cat litter boxes or consume undercooked meat.

In order to reduce the risk of acanthamoeba keratitis, do not wear contacts while swimming or rinse with anything other than approved contact lens solutions.

In order to reduce the risk of demodex, clean your eyelids regularly and maintain a routine for eyelid hygiene.

If there is ever a question or concern about a parasitic infection, reach out to your eye doctor.