Stephen H. Sinclair, MDErnesto L. Collazo, MD
Systemic lupus erythematosus is a disease which can involve every organ in the human body. It is no surprise, therefore, that it can involve not only the eyes but also the orbit (eye socket) around the eyes and the eyelids that house them. It may even involve the nerve connections from the eye to the brain. Before we can discuss eye problems in lupus, it is first necessary to understand the structure of the human eye. The eye can be compared to a photographic camera.
The camera contains a lens which focuses an image onto the film, located against the back wall of the camera. The eye is arranged in a similar fashion. It is protected by the eyelids which act as windshield wipers, spreading tears over the surface of the eye (the cornea) to keep the cornea moist and clear. The lids have a smooth inner lining known as the conjunctiva. The conjunctiva is essentially a membrane which also covers the front portion of the eyeball preventing objects such as dirt and contact lenses from getting behind the eye. The front surface of the eye is covered by the cornea, a transparent window similar to the crystal of a watch. Behind the cornea is the iris which may be of various colors (brown, blue, green, etc.) and acts similarly to the diaphragm of the camera by controlling the amount of light that enters the eye.
Behind the iris is the lens which, like the lens of the camera, focuses the image on the retina at the back of the eye. It is not composed of glass but rather is a bag of clear protein. The eye's outer wall or sclera, the white of the eye, provides structural strength. The inside layer of the eye, known as the retina, is the light sensitive layer that is similar to the film of the camera. It lies flat against the back inside wall of the eye. The nerve impulses which it produces are transmitted to the visual part of the brain through the optic nerve in the back of the eye.
Skin and Eyelids
Lupus can produce inflammatory lesions (or sores) of the eyelids. The lesions may be small and individual ("discoid") or they may b more widespread causing swelling, irritation and redness of the eyelids, and sometimes loss of the eyelashes. Over time these lesion, if untreated, may cause scarring which can distort the eyelids and prevent them from performing their function of blinking and wiping the front of the eye. Treatment usually consists of systemic (taken internally) or topical (applied locally) corticosteroids to decrease inflammation.
Conjunctiva
The conjunctiva may also become inflamed causing redness and tearing, although this does not occur often. The tear glands are located in the conjunctiva. When lupus affects the conjunctiva, causing inflammation and scarring, it may reduce tear production resulting in dryness of the eye (which is often associated with mouth and vaginal dryness and is known as sicca or Sjogren's Syndrome). With reduced wetting, the cornea can lose its clarity and become roughened and irritable as well as prone to infection (ulcers). Rarely inflammation of the sclera or iris may also occur. Again systemic or topical (eye drops in this case) corticosteroids are used to reduce the inflammation. In addition artificial tear preparations and ointments can be used to reduce the dryness and subsequent irritation. Infection or ulcers of the cornea require prompt and careful treatment with antibiotics.
Retina
By far the most common effect of systemic lupus erythematostis on the eye is injury to the blood vessels that supply the retina. Small retinal hemorrhages can result, as well as occlusions or blockages of the smaller retinal blood vessels. This causes damage to the retinal tissue due to lack of an adequate blood supply. Infrequently, larger arteries may also be occluded leading to loss of function in large areas of the retina. When this involves the center of the retina, known as the macula, a large area of central vision is lost. The optic nerve may also suffer from blockages of the blood vessels which supply it, resulting in loss of vision in the entire eye. In rare cases the blockages of blood vessels in the retina may be so severe and widespread that the retina may, in response to the blockages, attempt to develop new vessels. This process is termed "neovascularization." Such new vessels grow abnormally out from the surface of the retina into the central vitreous gel (the substance that fills the inside of the eye). They are prone to bleeding when stretched or pulled by the gel, resulting in severe vision loss. Although these abnormal blood vessels are rare in patients who are on adequate treatment for lupus, all lupus patients should be followed with periodic eye examinations because the blockages and abnormal vessel growth may occur without the patient noticing symptoms. If blockages or neovascularization are detected early, they may be treated with a laser. This procedure is usually done as an outpatient.
Central Nervous System
Involvement of the central nervous system is uncommon but, when it occurs, may be due to blood vessel inflammation and blockage within the brain. The resulting damage may affect the visual system in a variety of ways. These include defects or gray areas of the visual field in one or both eyes, eye movement abnormalities which can lead to double vision, disturbances in the function of the pupils, and damage to the optic nerve leading to loss of vision in one eye.
Complications of Systemic Drugs
Treatments for reducing the systemic inflammation of lupus (inflammation which can affect any area of the body) are vitally important to the well-being of the patient and also lessen the effect of inflammation on the eye, eyelids, or orbit. Some of the drugs which are used in the treatment of systemic lupus, however, can have side effects on the eyes. The long-term use of steroids, either systemic or topical, may cause the formation of cataracts. A cataract is a change in the lens of the eye which can affect the ability of the lens to focus. It can produce opacities or defects that create glare and haziness of vision. Most mild cataracts are treated with corrective eyeglasses or special lens filters. When the glare or haziness become such a problem that patients can no longer see well enough to go about their daily lives, then the lens with the cataract can be removed surgically and replaced with an artificial lens which restores the vision.
In addition, corticosteroids can lead to the development of' glaucoma, a condition in which an increase in the pressure within the eye causes damage to the optic nerve and an irreversible loss of' vision. This condition can be treated with medications to lower the pressure within the eye, therefore preventing further damage to the optic nerve. Periodic eye examinations are vital to the early detection and treatment of glaucoma. The use of antimalarials has become widespread in the treatment of lupus patients. One of the first of these, chloroquine, was found to have a significant toxic effect on the eye. Over the years the drug has a tendency to accumulate in the layer between the retina and the sclera, and in some cases this leads to severe destruction of the central retina with central vision loss.
A drug similar to chloroquine is more commonly used today. It is called hydroxychloroquine (Plaquenil). This drug is apparently not as toxic and vision loss is extremely rare, even with relatively high doses taken over several years. Lupus patients who are on Plaquenil are still checked carefully with periodic vision and field testing and evaluation of the retina. If toxic side effects to the retina do occur, they are detected early, and the drug can be stopped without any further retinal damage and no injury to vision.
=========================================================== This information is for "informational purposes" and is not meant to be used for medical diagnosis. Always consult your physician on matters such as this.
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