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Anterior Uveitis (Iritis)

Key Points ⚡

  • Uveitis: inflammation of the uveal tract (iris, ciliary body, choroid).
  • Anterior uveitis: most common type (50%), involves iris and ciliary body, presents as painful, photophobic red eye.
  • Aetiology: ~50% idiopathic; associated with HLA-B27 diseases (ankylosing spondylitis, reactive arthritis), autoimmune diseases (sarcoidosis, vasculitis), infections (toxoplasmosis, herpes), trauma, iatrogenic, malignancy.
  • Risk factors: age >20, previous uveitis episodes, HLA-B27 positivity.
  • Symptoms: painful red eye, photophobia, tearing; often unilateral but can be bilateral in systemic disease.
  • Clinical signs: ciliary injection, irregular pupil (posterior synechiae), cloudy cornea (cells in aqueous), hypopyon in severe cases.
  • Investigations: urinalysis, bloods (FBC, U&E, CRP, ESR), HLA-B27, ANA, serum ACE, infectious screen (TB, syphilis, toxoplasmosis, Lyme, HIV), OCT, chest/spinal X-rays.
  • Management: urgent ophthalmology referral within 24 hours, topical steroids, pupil dilators, systemic steroids/immunosuppressants if severe.
  • Complications: macular oedema, secondary cataract, raised intraocular pressure; relapses common, prognosis generally good with treatment.

Introduction

  • Uveitis is inflammation of the uveal tract; anterior uveitis affects the iris and ciliary body and causes a painful, red, photophobic eye.
  • Incidence: 25-50 cases per 100,000 persons; mean onset age 31 years.

Aetiology

  • 50% idiopathic.
  • Associated systemic diseases:
  • HLA-B27 related (ankylosing spondylitis, reactive arthritis, psoriatic arthritis, ulcerative colitis).
  • Autoimmune diseases: sarcoidosis, vasculitis.
  • Infectious: toxoplasmosis (most common), herpes simplex, herpes zoster, CMV, tuberculosis, Lyme disease, HIV, syphilis.
  • Trauma, iatrogenic (surgery, drugs like bisphosphonates, sulphonamides, rifabutin, cidofovir).
  • Cancer: leukemia, lymphoma, melanoma.

Anatomy

  • Eye layers:
  • Outer: cornea, sclera
  • Middle (uveal tract): iris, ciliary body, choroid
  • Inner: retina
  • Anterior uveitis = inflammation of iris and ciliary body (iridocyclitis).

Clinical Features

History

  • Symptoms develop over hours to days.
  • Usually unilateral in idiopathic/herpetic cases, bilateral in systemic conditions.
  • Symptoms: painful, red eye; photophobia; tearing.
  • May have systemic features: joint/back pain, rash, infective symptoms (fever, malaise).

Examination

  • Ciliary injection: conjunctival vessels around cornea dilated.
  • Irregular pupil from posterior synechiae (iris adheres to lens).
  • Cloudy cornea from cells/debris in aqueous humor, corneal edema.
  • Hypopyon: pus layer in anterior chamber in severe cases.
  • Slit lamp exam: circumferential redness, "smokey" anterior chamber.

Differential Diagnosis

  • Acute angle closure glaucoma: painful red eye with raised IOP.
  • Scleritis/episcleritis: red eye but usually no photophobia.
  • Infective keratitis: corneal damage visible.
  • Infectious conjunctivitis: less photophobia, different discharge.
  • Corneal foreign body or trauma: visible injury.
  • Endophthalmitis: severe pain, vision loss, marked inflammation.
  • Post-surgical anterior segment inflammation.

Investigations

Bedside

  • Urinalysis: screen for systemic vasculitis.

Laboratory

  • Based on suspected cause; systemic workup often not needed if idiopathic.
  • Tests: FBC, U&E, LFTs, HLA-B27, ANA, serum ACE, infectious disease screen (TB, syphilis, toxoplasmosis, Lyme, HIV).

Imaging

  • OCT: assess for macular oedema.
  • Chest X-ray: sarcoidosis, tuberculosis.
  • Spinal X-ray: ankylosing spondylitis.

Diagnosis

  • Clinical diagnosis supported by slit lamp findings.
  • Severity graded by SUN working group scheme based on anterior chamber cells.

Management

  • Urgent referral to ophthalmology (within 24 hours).
  • Topical steroids to reduce inflammation.
  • Pupil dilating drops (e.g., cyclopentolate) to relieve pain and prevent synechiae.
  • Treat underlying cause (antimicrobials if infectious).
  • Severe cases may need systemic steroids or immunosuppressants (methotrexate, mycophenolate, adalimumab).

Complications

  • Vision loss (due to macular oedema, cataract).
  • Raised intraocular pressure (secondary glaucoma).
  • Relapses common in younger patients.

Prognosis

  • Generally good with treatment; many cases self-limiting.
  • Regular follow-up necessary to monitor for complications or recurrence.

References

  • BMJ Best Practice. Uveitis – Symptoms, Diagnosis and Treatment. 2021.
  • Kanski’s Clinical Ophthalmology, 9th ed., Chapter 12, Uveitis.
  • MSD Manual Professional Edition. Overview of Uveitis – Eye Disorders.
  • NICE CKS. Uveitis. 2021.
  • Acute Angle-Closure Glaucoma
  • Age-related Macular Degeneration (ARMD)
  • Amblyopia
  • Ametropia
  • Anisocoria