Who it affects:

• Adults aged 20–50 are most frequently diagnosed, but it can occur at any age, including children.
• Women are slightly more likely than men (≈55 % vs. 45 %).
• Higher prevalence in people with autoimmune disorders, certain infections, or a family history of uveitis.

Prevalence: In the United States, an estimated 30–50 cases per 100,000 people develop iritis each year.² Worldwide, incidence ranges from 10 to 100 per 100,000, varying with geographic and socioeconomic factors.

Symptoms

Symptoms can develop suddenly or progress over several days. Most patients notice at least one of the following:

• Eye pain – aching or throbbing, often worse in bright light.
• Photophobia – heightened sensitivity to light.
• Redness – a deep, violaceous (purple‑red) hue around the cornea; the conjunctiva may also become pink.
• Blurred vision – may be mild to moderate; patients may notice “floaters” (tiny specks that drift across the visual field).
• Decreased visual acuity – in severe cases, vision can drop significantly.
• Headache – especially around the temples or forehead.
• Swollen eyelid – less common, but can accompany inflammation.
• Eye watering (tearing) – a reflex to irritation.

Symptoms often worsen in the first 24–48 hours and may improve temporarily with topical steroids, only to return if treatment is stopped too early.

Causes and Risk Factors

Primary (idiopathic) Iritis

In up to 50 % of cases, no specific cause is identified. These are termed “idiopathic” and are believed to involve an autoimmune reaction triggered by unknown environmental factors.

Infectious Causes

Several pathogens can directly infect the anterior uveal tract or trigger an immune response:

• Herpes simplex virus (HSV) and Varicella‑zoster virus (VZV) – common in older adults.
• Treponema pallidum (syphilis) – can cause chronic iritis.
• Toxoplasma gondii – especially in immunocompromised patients.
• Tuberculosis (Mycobacterium tuberculosis) – more prevalent in endemic regions.
• Other bacteria – e.g., Haemophilus influenzae, Staphylococcus aureus (rare).

Systemic Autoimmune / Inflammatory Diseases

The iris can be a target of systemic inflammation. Conditions strongly associated with iritis include:

• Ankylosing spondylitis (up to 30 % develop uveitis).³
• Reactive arthritis (formerly Reiter’s syndrome).
• Sarcoidosis – non‑caseating granulomas can involve the eye.
• Behçet’s disease – often causes recurrent iritis.
• Inflammatory bowel disease (Crohn’s, ulcerative colitis).
• Lupus erythematosus and Rheumatoid arthritis.

Trauma & Miscellaneous

• Penetrating or blunt eye injury.
• Intra‑ocular surgery (e.g., cataract extraction, laser procedures).
• Exposure to certain chemicals or toxins.

Risk Factors

• History of previous uveitis episodes.
• Genetic predisposition – HLA‑B27 positivity markedly increases risk.
• Smoking – associated with higher incidence of autoimmune uveitis.
• Use of immunosuppressive medication that predisposes to infections.

Diagnosis

Prompt, accurate diagnosis is essential to prevent vision loss.

Clinical Examination

• Slit‑lamp biomicroscopy – the gold‑standard exam; reveals cells and flare in the anterior chamber, iris synechiae (adhesions), and keratic precipitates.
• Visual acuity testing – establishes baseline vision.
• Tonometry – measures intra‑ocular pressure; can be low (due to ciliary body inflammation) or high (if steroids are used).

Ancillary Tests

• Fundus examination after pupil dilation – to rule out posterior involvement.
• Fluorescein angiography – evaluates retinal vasculature if posterior segment disease is suspected.
• Optical coherence tomography (OCT) – detects macular edema.
• Laboratory work‑up – guided by clinical suspicion:
  • HLA‑B27 typing.
  • Serologic tests for syphilis (RPR/VDRL), Lyme disease, toxoplasmosis, TB (Quantiferon‑TB Gold), and viral PCR from aqueous humor if infection is likely.
  • Inflammatory markers (ESR, CRP) and ANA, RF for systemic autoimmune disease.

Differential Diagnosis

Conditions that can mimic iritis include conjunctivitis, acute angle‑closure glaucoma, keratitis, and scleritis. A thorough exam distinguishes these entities.

Treatment Options

Treatment aims to suppress inflammation, control pain, prevent complications, and treat any underlying cause.

Medications

1. Topical corticosteroids (e.g., prednisolone acetate 1 %).
   • First‑line for most cases.
   • Dosing: hourly during acute phase, then tapered over weeks.
   • Monitor intra‑ocular pressure (IOP) because steroids can raise IOP.
2. Cycloplegic agents (e.g., atropine 1 % or cyclopentolate).
   • Relieve pain by paralyzing the ciliary muscle.
   • Prevent formation of posterior synechiae.
3. Non‑steroidal anti‑inflammatory drugs (NSAIDs) eye drops (e.g., diclofenac).
   • Useful for mild cases or as steroid‑sparing adjuncts.
4. Systemic corticosteroids (oral prednisone 0.5 mg/kg).
   • Indicated when inflammation is severe, bilateral, or unresponsive to topical therapy.
5. Immunomodulatory therapy (IMT) for chronic or recurrent disease:
   • Antimetabolites (methotrexate, mycophenolate mofetil).
   • Calcineurin inhibitors (tacrolimus, cyclosporine).
   • Biologics (adalimumab, infliximab) especially for HLA‑B27 associated uveitis or Behçet’s disease.
   • Managed by a uveitis specialist.
6. Antimicrobial therapy when an infection is identified:
   • Oral antivirals (acyclovir, valacyclovir) for HSV/VZV.
   • Antibiotics (penicillin, doxycycline) for syphilis or TB.
   • Antiparasitics (pyrimethamine plus sulfadiazine) for toxoplasmosis.

Procedures

• Posterior sub‑Tenon’s triamcinolone injection – delivers a depot of steroid for refractory cases.
• Intravitreal steroid implant (Ozurdex®) – rarely used for anterior uveitis but can address concurrent posterior inflammation.
• Laser iridotomy – indicated if peripheral anterior synechiae cause angle‑closure and IOP rise.

Lifestyle & Supportive Measures

• Wear sunglasses to decrease photophobia.
• Use artificial tears for secondary dry eye.
• Avoid smoke exposure and limit alcohol, which may worsen inflammation.
• Adhere strictly to medication schedule; sudden cessation of steroids can trigger rebound inflammation.

Living with Iritis (Uveitis)

Daily Management Tips

• Medication diary – record drop times, dosage, and any side effects.
• Regular follow‑up – initially every 1‑2 weeks until quiescence, then every 2‑3 months for chronic disease.
• Protective eyewear – UV‑blocking sunglasses outdoors; safety goggles if working with dust or chemicals.
• Screen time breaks – 20‑20‑20 rule (every 20 min, look at something 20 ft away for 20 sec) to reduce eye strain.
• Healthy diet – omega‑3 rich foods (fish, flaxseed) and antioxidant‑rich fruits may support ocular health.
• Stress management – stress can exacerbate autoimmune flare‑ups; consider mindfulness, yoga, or counseling.

Psychosocial Support

Living with a chronic eye condition can be anxiety‑provoking. Join patient groups (e.g., American Uveitis Society), seek counseling if vision loss fears arise, and keep open communication with your ophthalmologist.

Prevention

While idiopathic iritis cannot be entirely prevented, risk can be reduced by addressing modifiable factors:

• Control systemic diseases (e.g., maintain remission of ankylosing spondylitis with appropriate therapy).
• Prompt treatment of ocular infections and proper hygiene (hand washing, avoiding eye rubbing).
• Vaccinate against varicella and shingles, especially for older adults, to lower viral‑induced uveitis risk.
• Quit smoking – reduces systemic inflammation.
• Use protective eyewear during high‑risk activities (sports, construction).
• Regular eye examinations, especially if you have an associated systemic condition.

Complications

If inflammation persists or is inadequately treated, several sight‑threatening complications may develop:

• Posterior synechiae – adhesions between iris and lens, potentially leading to cataract formation.
• Cataract – both inflammation‑related and steroid‑induced.
• Glaucoma – either from steroid‑induced IOP rise or angle closure due to synechiae.
• Macular edema – swelling of the central retina, causing central vision loss.
• Band keratopathy – calcium deposition in the cornea.
• Vision loss – permanent if complications are not caught early.

Early detection and aggressive control of inflammation dramatically lower the risk of these outcomes.

When to Seek Emergency Care

References

1. Centers for Disease Control and Prevention. Vision Health Initiative. https://www.cdc.gov/visionhealth/vision.htm
2. Freund, K. B. et al. “Epidemiology of Uveitis.” American Journal of Ophthalmology, 2010;149(5):805‑812. PMCID: PMC4247907
3. Mayo Clinic. Ankylosing Spondylitis – Symptoms and Causes. https://www.mayoclinic.org
4. American Uveitis Society. Clinical Guidelines for Uveitis Management. 2022. https://uveitis.org
5. National Institute of Allergy and Infectious Diseases. “Uveitis.” NIH. https://www.niaid.nih.gov
6. World Health Organization. “Global Estimates of Visual Impairment.” 2021. https://www.who.int