Systemic Lupus Erythematosus (SLE) is a chronic, autoimmune disease that causes widespread inflammation and can affect nearly any part of the body, including the eyes. Ocular involvement occurs in up to one-third of people with SLE, and the resulting inflammation can affect the eye’s delicate structures, leading to a range of visual problems. Blurry vision is a common symptom resulting from this damage, which can range from a minor inconvenience to a sign of a more serious, sight-threatening event.
How Lupus Triggers Ocular Damage
The primary mechanism by which SLE affects the eyes stems from uncontrolled, systemic inflammation. This inflammatory state causes the immune system to produce autoantibodies and immune complexes, which are essentially clumps of antibodies and antigens. These complexes circulate throughout the body and deposit in the walls of small blood vessels, including those supplying the eye structures.
This deposition triggers vasculitis, the inflammation of the blood vessel walls. When tiny arteries and capillaries within the eye become inflamed, the inner lining swells, narrowing the vessel and restricting blood flow. This lack of sufficient blood and oxygen, known as ischemia, is the root cause of many lupus-related vision problems. The inflammation can also directly damage nerve tissue, which is highly sensitive to even minor interruptions in its blood supply.
In the retina, this vascular damage leads to micro-infarctions, which are small areas of tissue death caused by a lack of blood. Antiphospholipid antibodies, which promote clotting, can further complicate this process by directly causing blockages in the retinal blood vessels. The eyes offer a unique window into this systemic vascular damage, as they are the only place where small blood vessels can be directly observed.
Manifestations in Specific Eye Structures
Lupus-related damage commonly manifests as lupus retinopathy in the retina, the light-sensitive layer at the back of the eye. This involves inflammation of the retinal blood vessels, which can cause hemorrhages, fluid leakage, and white, fluffy patches known as cotton-wool spots. These changes often lead to blurry vision, blind spots, or visual distortion, and the severity of the retinopathy often correlates with overall disease activity.
Another serious manifestation is optic neuritis, involving inflammation of the optic nerve that transmits visual information from the eye to the brain. This condition occurs in a small percentage of lupus patients but can lead to sudden, severe vision loss and pain, especially when moving the eye. The inflammation can be caused by direct nerve damage or by ischemic optic neuropathy, a lack of blood flow to the nerve.
Lupus can also affect the outer coating of the eyeball, leading to episcleritis or scleritis. Episcleritis is a milder inflammation causing redness and mild discomfort. Scleritis is a deeper, more painful inflammation of the white part of the eye, which can cause significant pain, light sensitivity, and blurred vision due to structural changes. A frequent, less severe symptom is dry eye syndrome, which causes a sandy, gritty feeling, redness, and temporary blurring due to poor tear production.
Vision Changes Related to Lupus Treatment
Hydroxychloroquine, commonly known as Plaquenil, is a mainstay of lupus treatment but carries a small risk of retinal toxicity. This toxicity is cumulative and dose-dependent, meaning the risk increases with the total amount of the drug taken over many years. The drug can damage the photoreceptors and retinal pigment epithelium, leading to permanent vision loss that may continue to progress even after the medication is stopped.
Corticosteroids, such as prednisone, are frequently used to control acute lupus flares and chronic inflammation. However, long-term or high-dose systemic corticosteroid therapy significantly increases the risk of developing two specific eye conditions. These are posterior subcapsular cataracts, which cause clouding in the central lens and often require earlier surgery, and steroid-induced glaucoma, which occurs when the medication raises pressure inside the eye. The elevated intraocular pressure can damage the optic nerve and result in a gradual loss of peripheral vision.
Monitoring and Management of Ocular Symptoms
Given the potential for serious ocular complications, regular, specialized eye monitoring is essential. People taking hydroxychloroquine should have a baseline eye examination soon after starting the medication to establish a reference point. Annual screening is recommended after five years of continuous use, or earlier if specific risk factors, such as high daily dosage relative to body weight or kidney impairment, are present.
Screening for hydroxychloroquine toxicity involves specific tests like Optical Coherence Tomography (OCT) and visual field testing to detect subtle retinal damage. Patients on long-term systemic corticosteroids must also be monitored for cataracts and glaucoma, which often involves measuring the intraocular pressure. Seeking immediate emergency care is necessary for any sudden vision loss, severe eye pain, or the rapid onset of new blind spots.
Treatment for active ocular lupus involves managing the underlying systemic inflammation. For severe manifestations like optic neuritis or retinal vasculitis, high-dose intravenous corticosteroids are often used to quickly reduce inflammation. Systemic immunosuppressive drugs are often added to control the disease and prevent future flares that could threaten vision. For less severe issues like dry eyes, over-the-counter artificial tears are typically the first line of management.