Primary Keyword: Uveitis causes

Secondary Keywords: causes of uveitis, autoimmune uveitis, infectious uveitis, eye inflammation, uveitis risk factors, anterior uveitis causes, posterior uveitis causes

Uveitis Causes: Why Does Uveitis Occur?

Uveitis is an inflammatory disease that affects the uvea, the middle vascular layer of the eye. While the inflammation itself damages eye tissues, it is usually triggered by an underlying medical condition, infection, injury, or an abnormal immune response. In many cases, however, no specific cause can be identified.

Understanding the cause of uveitis is essential because treatment depends on the underlying trigger. For example, infectious uveitis requires antimicrobial therapy, whereas autoimmune uveitis is treated with medications that suppress inflammation.

Without timely diagnosis and treatment, uveitis can lead to cataracts, glaucoma, retinal damage, and permanent vision loss.

Table of Contents

• What causes uveitis?
• How inflammation develops
• Autoimmune causes
• Infectious causes
• Eye injury and surgery
• Medication-induced uveitis
• Idiopathic uveitis
• Risk factors
• Diagnosis of the underlying cause
• Treatment based on the cause
• Can uveitis be prevented?
• Frequently Asked Questions

What Causes Uveitis?

Uveitis develops when inflammatory cells enter the eye and damage the iris, ciliary body, choroid, retina, or nearby structures.

The major causes include:

• Autoimmune diseases
• Infections
• Eye trauma
• Eye surgery
• Certain medications
• Cancers (rare)
• Idiopathic (unknown cause)

Approximately 30–50% of uveitis cases are idiopathic, meaning no definite cause is found despite extensive evaluation.

How Does Uveitis Develop?

Normally, the immune system protects the body from bacteria, viruses, and other harmful organisms. In uveitis, inflammation occurs when:

• The immune system mistakenly attacks healthy eye tissues (autoimmune uveitis).
• Infectious organisms invade the eye.
• Trauma or surgery disrupts the eye's protective barriers.
• Certain medications trigger an inflammatory reaction.

The resulting inflammation can damage the retina, optic nerve, lens, and other structures if not treated promptly.

1. Autoimmune Diseases (Most Common Non-Infectious Cause)

Autoimmune disorders are among the leading causes of non-infectious uveitis. In these conditions, the body's immune system mistakenly attacks its own tissues, including the eye.

Common Autoimmune Conditions Associated with Uveitis

Ankylosing Spondylitis

A chronic inflammatory disease affecting the spine and sacroiliac joints. It is strongly associated with HLA-B27-positive anterior uveitis.

Psoriatic Arthritis

People with psoriasis may develop inflammation in the joints and eyes, leading to recurrent uveitis.

Rheumatoid Arthritis

Although less commonly linked than other autoimmune diseases, rheumatoid arthritis can cause chronic ocular inflammation.

Juvenile Idiopathic Arthritis (JIA)

Children with JIA are at risk of chronic anterior uveitis, which may progress silently without noticeable symptoms.

Behçet Disease

A multisystem inflammatory disorder that can cause severe recurrent uveitis affecting both the anterior and posterior segments of the eye.

Sarcoidosis

This disease causes granuloma formation in various organs, including the lungs and eyes, resulting in chronic uveitis.

Inflammatory Bowel Disease

Both Crohn's disease and ulcerative colitis are associated with episodes of uveitis.

Systemic Lupus Erythematosus (SLE)

Lupus may cause inflammation of multiple eye structures, including the uvea and retina.

2. Infectious Causes of Uveitis

Several infectious organisms can trigger uveitis.

Viral Infections

Herpes Simplex Virus (HSV)

Often causes anterior uveitis with elevated intraocular pressure.

Herpes Zoster Virus (Shingles)

Can produce severe inflammation following shingles involving the forehead or eye.

Cytomegalovirus (CMV)

Frequently affects people with weakened immune systems.

Bacterial Infections

Tuberculosis (TB)

Tuberculosis can involve the eye and produce chronic posterior uveitis.

Syphilis

Known as the "great imitator," syphilis can cause almost any type of uveitis.

Lyme Disease

Although uncommon, Lyme disease may lead to inflammatory eye disease.

Parasitic Infections

Toxoplasmosis

The most common infectious cause of posterior uveitis worldwide. It causes retinal inflammation and characteristic retinal scars.

Fungal Infections

Fungal uveitis is uncommon but may occur after:

• Eye injury involving plant material
• Immunosuppression
• Bloodstream fungal infections

3. Eye Injury (Traumatic Uveitis)

Physical injury can trigger inflammation.

Examples include:

• Blunt eye trauma
• Penetrating injuries
• Chemical burns
• Thermal burns
• Foreign body injuries

Inflammation may develop immediately or several days after the injury.

4. Eye Surgery

Inflammation occasionally develops after procedures such as:

• Cataract surgery
• Vitrectomy
• Glaucoma surgery
• Corneal transplantation
• Retinal surgery

Most postoperative inflammation is temporary, but persistent inflammation requires prompt evaluation.

5. Medication-Induced Uveitis

Although rare, certain medications may trigger uveitis.

Examples include:

• Rifabutin
• Cidofovir
• Bisphosphonates
• Immune checkpoint inhibitors
• Some newer biologic therapies

Stopping or changing the medication under medical supervision often resolves the inflammation.

6. Cancer and Masquerade Syndromes

Rarely, eye inflammation is caused by conditions that mimic uveitis rather than true inflammation.

Examples include:

• Primary intraocular lymphoma
• Leukemia
• Metastatic cancer
• Ocular melanoma (occasionally)

These conditions require specialised investigation because treatment differs significantly from inflammatory uveitis.

7. Idiopathic Uveitis

Even after extensive investigations, many patients have idiopathic uveitis, meaning the exact cause remains unknown.

Although no specific trigger is identified, treatment focuses on controlling inflammation and preventing recurrence.

Risk Factors for Developing Uveitis

People are at greater risk if they have:

• Autoimmune diseases
• Previous episodes of uveitis
• Eye injuries
• Recent eye surgery
• Chronic infections
• Immunosuppression
• Smoking
• Family history of inflammatory diseases

Symptoms That May Suggest Uveitis

The symptoms vary depending on the affected part of the eye but commonly include:

• Eye redness
• Eye pain
• Blurred vision
• Floaters
• Sensitivity to light (photophobia)
• Reduced vision
• Excessive tearing
• Headache around the eye

Seek urgent ophthalmic evaluation if these symptoms develop suddenly.

How Doctors Identify the Cause

Determining the underlying cause often requires a combination of eye examination and systemic investigations.

Eye Examination

• Visual acuity test
• Slit-lamp examination
• Dilated retinal examination
• Intraocular pressure measurement

Imaging

• Optical Coherence Tomography (OCT)
• Fundus photography
• Fluorescein angiography
• B-scan ultrasonography (when needed)

Blood Tests

Depending on the clinical picture, doctors may request:

• Complete blood count
• Inflammatory markers (ESR, CRP)
• HLA-B27 testing
• Syphilis serology
• Tuberculosis screening
• Autoimmune antibody tests
• ACE levels (for sarcoidosis)
• HIV testing (when appropriate)

Additional imaging, such as a chest X-ray or CT scan, may be performed if a systemic inflammatory disease is suspected.

Treatment Based on the Cause

Treatment aims to control inflammation and address the underlying condition.

Autoimmune Uveitis

• Corticosteroid eye drops
• Oral corticosteroids
• Immunosuppressive drugs
• Biologic therapies

Infectious Uveitis

• Antibiotics
• Antiviral medications
• Antifungal agents
• Antiparasitic drugs

Traumatic Uveitis

• Anti-inflammatory eye drops
• Cycloplegic drops
• Monitoring for complications

Medication-Induced Uveitis

• Review and adjust the offending medication under medical supervision
• Anti-inflammatory treatment as needed

Can Uveitis Be Prevented?

Not all cases can be prevented, but the following measures may reduce your risk:

• Manage autoimmune diseases effectively.
• Treat infections promptly.
• Wear protective eyewear during sports and hazardous work.
• Stop smoking.
• Attend regular eye examinations if you have recurrent uveitis or a systemic inflammatory condition.
• Follow your ophthalmologist's treatment plan carefully.

Frequently Asked Questions

What is the most common cause of uveitis?

In many populations, autoimmune diseases are the most common cause of non-infectious uveitis, while toxoplasmosis is a common infectious cause of posterior uveitis.

Can stress cause uveitis?

Stress is not considered a direct cause, but it may influence immune function and could contribute to flare-ups in susceptible individuals.

Is uveitis hereditary?

Most cases are not inherited directly, although genetic factors such as HLA-B27 can increase susceptibility.

Can infections outside the eye cause uveitis?

Yes. Infections such as tuberculosis, syphilis, herpes, and toxoplasmosis can trigger inflammation inside the eye.

Can uveitis recur?

Yes. Recurrence is common, particularly when uveitis is associated with autoimmune diseases, making regular follow-up essential.

Key Takeaways

• Uveitis has many potential causes, including autoimmune diseases, infections, trauma, surgery, medications, and, in some cases, unknown factors.
• Identifying the underlying cause is essential because treatment varies depending on the trigger.
• Autoimmune conditions such as ankylosing spondylitis, Behçet disease, sarcoidosis, and juvenile idiopathic arthritis are major causes of non-infectious uveitis.
• Infectious causes include herpes viruses, tuberculosis, syphilis, toxoplasmosis, and fungal infections.
• Early diagnosis and appropriate treatment help prevent complications such as cataract, glaucoma, retinal damage, and permanent vision loss.

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