While gout is widely recognized for its impact on joints, it can also affect the eyes. This less common manifestation, often termed ocular gout, involves the same underlying biological processes that cause joint pain and inflammation. This article explores how gout can impact eye health, its symptoms, and approaches to diagnosis and management.
Gout and Its Ocular Manifestations
Gout is an inflammatory arthritis characterized by the accumulation of uric acid crystals, primarily in the joints. These monosodium urate (MSU) crystals form when uric acid levels are elevated in the blood, leading to sudden pain, swelling, and redness. While joints are the most common site for these deposits, MSU crystals can also settle in extra-articular tissues, including various parts of the eye.
The eye’s unique environment, possibly with lower temperatures and a specific chemical composition, can promote uric acid crystal deposition. This crystal deposition can lead to inflammation and damage within ocular tissues. Affected structures include the conjunctiva (the clear membrane covering the white part of the eye), and the episclera and sclera (the white outer layers of the eyeball).
Beyond these outer layers, the cornea (the eye’s transparent front surface) can develop crystal deposits. The uvea (the middle layer comprising the iris, ciliary body, and choroid) may also experience inflammation. In some instances, these uric acid deposits can form visible nodules, called tophi, on ocular tissues, including the eyelids. Deposits have also been reported in the lens, orbit, and, in rare cases, the retina.
Recognizing Eye Symptoms
When gout affects the eyes, symptoms vary based on the specific structures involved. General indicators include eye redness, pain, irritation, and sensitivity to light, often with blurred or decreased vision. These symptoms are not unique to ocular gout and can signal various eye conditions, underscoring the importance of professional medical evaluation.
If the conjunctiva is affected, individuals might experience persistent red eyes, a foreign body sensation, or a gritty feeling. Small, yellowish nodules (tophi) can sometimes be observed on the conjunctiva, and subconjunctival hemorrhage or changes in blood vessel appearance may also occur.
Involvement of the sclera or episclera can cause localized redness, tenderness, or a deep aching pain in the eye.
Inflammation of the uvea (uveitis) can lead to eye pain, light sensitivity, and redness around the iris. Patients may also notice floaters or experience blurred vision.
When the cornea is involved, visible crystal deposits might appear on its surface, causing irritation, pain, and potential changes in vision. Additionally, gout has been associated with dry eye symptoms, including discomfort and alterations in the tear film.
Diagnosis and Management
Diagnosing ocular gout requires a thorough evaluation by an eye care professional, such as an ophthalmologist. The diagnostic process begins with a comprehensive medical history, including any pre-existing gout diagnosis. A detailed eye examination allows inspection of eye structures for crystal deposits or inflammation.
Blood tests to measure uric acid levels are also part of the diagnostic workup, as elevated levels are a hallmark of gout. Advanced imaging or analysis of fluid samples from the eye might confirm uric acid crystals. Since eye symptoms can stem from various causes, these steps help differentiate ocular gout from other conditions.
Managing ocular gout involves addressing both acute eye inflammation and underlying systemic gout. During a flare-up, treatment focuses on reducing inflammation and pain. This often includes anti-inflammatory medications like nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids, administered as topical eye drops or oral medications.
For long-term management, controlling uric acid levels is essential to prevent recurrent ocular episodes. This involves urate-lowering therapy (ULT) with medications like allopurinol or febuxostat, which decrease uric acid production or enhance its excretion. Supportive care, including pain relief and rest, also plays a role in managing symptoms and promoting recovery.