Lyme disease is a tick-borne disease that often goes unrecognized until it has affected many parts of the body, including the eyes. This section of Eye Facts will describe how early recognition and treatment can prevent visual loss or other severe consequences.
Lyme disease is named after the Connecticut community where the first American cases were reported in 1977. The children affected had what appeared to be juvenile arthritis after first having a rash.
What causes lyme disease?
Lyme disease results from a bacterial infection transmitted by a tick bite. The tick responsible for spreading the disease is the ixodes dammini species. These insects infest white-tailed deer and white-footed mice. Humans are exposed to the disease by coming in contact with an environment (commomly rural or suburban areas) where either of these animals live. The risk of being bitten occurs when a person’s bare arms or legs come into contact with leaves and grass on which the ticks linger.
In Europe, years before the recognition of lyme disease in the United States, a different species of ixodes tick was found to spread a rash and meningitis (an inflammation in the brain). These early cases are now believed to have been lyme disease.
A spirochete, or spiral bacterium, called Borrelia burgodrferi, is the cause of lyme disease. It has been found on Ixodes ticks and in patients with lyme disease.
Where does lyme disease usually occur?
In the United States, lyme disease is most prevalent in wild or heavily wooded areas in certain regions. These include the Northeast, the upper Midwest (Wisconsin and Minnesota) and the Pacific Northwest (California and Oregon). The disease also is becoming more common in suburban areas where there are large deer populations.
What are the symptoms?
The initial symptom in most persons infected with lyme disease (60 to 80 percent) is a red, spreading rash on the skin around the tick bite. This rash is known as erythema migrans. Sometimes a fever, flu-like symptoms and swollen glands accompany the rash. If left untreated, the rash fades in three to four weeks, but it can recur in some people.
Up to 50 percent of patients with lyme disease do not remember the initial rash or being bitten by a tick. Therefore, some people do not receive treatment right away. Without treatment, the infection can spread through the bloodstream into the joints, brain, eyes, and/or heart. Excruciating headaches may occur.
Three weeks to several months after the tick bit, 15 to 20 percent of patients develop neurologic disease or meningitis. The most common nerve-related problem is facial palsy (drooping of the muscles on one or both sides of the face). Bell’s palsy is a common term for paralysis on one side of the face.
Arthritis occurs in many persons with lyme disease, usually six months or longer after the tick bite. Four to eight percent of those with the disease develop cardiac involvement, usually heart block. This can in rare instances be fatal.
How does lyme disease affect the eye?
Fortunately, involvement of the eye is uncommon in lyme disease. But when the eyes can be affected in many different ways by the disease.
In the early stage of the disease, many persons have conjunctivitis. In this condition, commonly called pink eye, the eyes are red and uncomfortable, and there is a discharge of pus. Unlike many forms of conjunctivitis, the type that occurs in lyme disease is not contagious.
In later stages of the disease, inflammation of the eye may develop. Parts of the eye that may be affected include the uvea, the middle layer inside the eye, the cornea, part of the outer coat of the eye; the iris, the colored circle around the pupil, and the choroid, a layer of blood vessels in the eye. Ocular symptoms can include sensitivity to light and floaters (spots in front of the eyes).
Inflammation of the optic nerve (optic neuritis) also can occur, which results in visual loss. Loss of vision can result from inflammation in the brain as well.
Persons who develop Bell’s palsy may be unable to blink or close their eyes. This dries the cornea and can result in an infection or even a hole in the cornea, which can endanger vision if not treated promptly.
How is lyme disease diagnosed?
Lyme disease can be difficult to diagnose because many patients are unaware of the tick bite or the rash (if they had it). Another problem is that some of the nervous system signs and symptoms can mimic another disease, multiple sclerosis. When a physician suspects lyme disease, blood tests may help in the diagnosis. Unfortunately, none of the blood tests available are highly accurate. Because of the difficulties of diagnosis, some persons are misdiagnosed as having lyme disease, and in some other persons the diagnosis is suspected but never confirmed.
In addition to blood testing, another way to confirm an uncertain diagnosis is to test a patient’s response to a trial of therapy.
What is the treatment?
In early stages of lyme disease, when the rash is apparent, the bacterial infection is treated successfully with oral antibiotics. These include doxycycline or tetracycline.
In late stages, when eye disease, arthritis or neurologic disease is present, therapy consists of intravenous antibiotics (e.g., penicillin or ceftriaxone). However, in late stages antibiotics may be effective only to a certain extent or may even fail to work. In these cases, neurologic damage may progress or blindness may result.
Although much is now known about lyme disease, better ways to diagnose and treat it are still needed. Early recognition of the symptoms is important in avoiding severe medical problems later.
Lyme disease can be prevented. If you are in an area where ticks live, avoid wearing shorts and short-sleeved shirts; cover as much of your skin as possible. Use an insect repellent on your hands and face. If you live in an area where ticks are prevalent, watch out for signs of lyme disease. Immediately seek medical attention after a tick bite of if you develop a spreading rash.