Anterior Uveitis

Overview

Anterior uveitis represents inflammation affecting the anterior uveal tract, specifically the iris and ciliary body. It is the most common anatomical form of uveitis.¹ The condition encompasses a broad spectrum of etiologies, including infectious agents (particularly viruses), systemic inflammatory diseases, and idiopathic cases. Accurate etiologic diagnosis requires systematic clinical characterization, examination of the posterior segment to exclude masquerade syndromes, and directed laboratory investigation based on clinical findings.^1,2 Recent advances in molecular diagnostics have revealed viral causes in many cases previously classified as idiopathic.³

Epidemiology & Risk Factors

Cytomegalovirus anterior uveitis, a specific viral subtype, is highly prevalent in Asia with a higher incidence in men.⁴ The overall epidemiology of anterior uveitis varies by geographic region and population studied, with different causative organisms and systemic associations predominating in different areas. Risk factors depend on the specific etiology, with HLA-B27 positivity associated with recurrent acute anterior uveitis, and immunocompromised states predisposing to certain infectious forms.¹

Pathophysiology

The pathophysiology of anterior uveitis varies by etiology. In viral anterior uveitis, direct viral infection and replication in uveal tissues trigger inflammatory responses. Herpes simplex virus, varicella-zoster virus, cytomegalovirus, and rubella virus have been identified as causative agents.⁵ These viral infections can manifest through various mechanisms including direct tissue damage, iris atrophic changes, and corneal endothelial involvement.⁵ In autoimmune forms, immune dysregulation leads to inappropriate inflammatory responses targeting uveal tissues. HLA-B27-associated uveitis involves specific immune pathway activation, while juvenile idiopathic arthritis-associated disease reflects systemic autoimmune processes affecting the eye.¹

Clinical Presentation

Patients with anterior uveitis typically present with eye pain, photophobia, blurred vision, and redness. The clinical presentation varies significantly based on etiology and disease pattern. Viral anterior uveitis commonly presents with elevated intraocular pressure, corneal involvement, and iris atrophic changes.⁵ Acute cytomegalovirus anterior uveitis may resemble Posner-Schlossman syndrome with recurrent hypertensive iritis, while chronic forms may resemble Fuchs uveitis with persistently elevated intraocular pressure.⁴ Unilateral versus bilateral involvement is a critical distinguishing feature, as is the acute versus chronic nature of inflammation.^1,2

Exam Findings

Key examination findings in anterior uveitis include:

• Anterior chamber inflammation: Cell and flare visible on slit-lamp examination
• Keratic precipitates: Fine, diffuse, stellate keratic precipitates suggest viral etiology, while larger mutton-fat keratic precipitates indicate granulomatous inflammation³
• Iris changes: Iris atrophy may be present, particularly in viral anterior uveitis^5,3
• Intraocular pressure: Elevated pressure is common in viral anterior uveitis and should raise suspicion for viral etiology^5,3
• Corneal involvement: Endothelitis or keratitis may accompany viral anterior uveitis⁵
• Posterior synechiae: Adhesions between iris and lens may develop
• Posterior segment examination: Essential to rule out masquerade syndromes and assess for posterior involvement^1,2

Classification

Anterior uveitis is classified along several clinical axes that guide diagnostic workup and management. The primary classification distinguishes unilateral versus bilateral disease, as this significantly narrows the differential diagnosis.^1,2 A second critical distinction is granulomatous versus nongranulomatous inflammation based on the character of keratic precipitates and other inflammatory features.^1,2 Temporal patterns include acute (sudden onset, limited duration), recurrent (repeated episodes with intervening quiet periods), and chronic (persistent inflammation lasting months).⁶ Additional classification considers anatomical isolation versus associated posterior or systemic involvement, and infectious versus noninfectious etiology.²

Differential Diagnosis

The differential diagnosis of anterior uveitis includes:

• Viral etiologies: Herpes simplex virus, varicella-zoster virus, cytomegalovirus, rubella virus^5,3
• HLA-B27-associated conditions: Ankylosing spondylitis, reactive arthritis, inflammatory bowel disease, psoriatic arthritis
• Juvenile idiopathic arthritis: Particularly in children with chronic bilateral disease¹
• Sarcoidosis: Granulomatous inflammation with systemic manifestations
• Syphilis: Must be excluded before initiating corticosteroid therapy⁶
• Posner-Schlossman syndrome: Recurrent hypertensive iritis that may represent viral anterior uveitis⁴
• Fuchs uveitis syndrome: Chronic unilateral disease with heterochromia and elevated intraocular pressure⁴
• Masquerade syndromes: Including intraocular malignancies^1,2
• Idiopathic: Diagnosis of exclusion after appropriate workup

There is considerable overlap between clinical manifestations of different viral anterior uveitides and noninfectious hypertensive anterior uveitis syndromes.³

Management

Initial Assessment and Workup

The priority in evaluating anterior uveitis is ruling out infectious etiologies before initiating corticosteroid therapy.² For severe, bilateral, recurrent, or chronic anterior uveitis, chest radiography and serologic testing for syphilis, HLA-B27, and angiotensin-converting enzyme are appropriate routine investigations.⁶ Additional testing should be guided by clinical findings and regional epidemiology, particularly when considering expensive and invasive modalities, as investigations obtained without clinical orientation are of limited utility.⁶

For suspected viral anterior uveitis, diagnostic tests including polymerase chain reaction and Goldmann-Witmer coefficient analysis on aqueous humor may help identify specific viral etiologies to guide treatment.⁵

Medical Management

Most cases of anatomically isolated anterior uveitis resolve with topical corticosteroids.⁶ Treatment intensity should be adapted according to etiology and disease severity.¹

For viral anterior uveitis, acyclovir remains the mainstay of therapy for herpes simplex virus and varicella-zoster virus infections.³ Cytomegalovirus anterior uveitis responds to ganciclovir, though relapse rates are high and prolonged therapy may be required.³ Both oral valganciclovir and topical ganciclovir can produce positive clinical outcomes for cytomegalovirus anterior uveitis, with higher concentration and frequency beneficial in chronic disease.⁴ Early antiviral treatment reduces the risk of requiring glaucoma surgery.⁴ An extended antiviral course can prevent relapses but should be limited to six months to prevent drug resistance and side effects.⁴

Corticosteroids should be used with caution when virus diagnostic tests are not available, given the overlap between viral and noninfectious presentations.³

Immunomodulatory Therapy

Systemic immunomodulatory therapy should be considered in patients who respond poorly to corticosteroids, develop corticosteroid-related side effects that limit use, require high doses to maintain disease remission, or have concomitant systemic inflammatory disease.⁶ Comprehensive ophthalmologists should feel comfortable comanaging patients requiring conventional disease-modifying antirheumatic drugs and antimetabolite therapy (methotrexate, azathioprine, mycophenolate mofetil) with rheumatologists.⁶

Biologics have significantly changed management and prevention of some forms of anterior uveitis, particularly HLA-B27-associated and juvenile idiopathic arthritis-associated disease.^1,2

Referral Considerations

When uveitis quiescence cannot be achieved despite maximally tolerated antimetabolite therapy, patients should be referred to a uveitis specialist for consultation and consideration of immunomodulatory therapy escalation.⁶ The timing of uveitis referral may depend on local health care system factors.⁶

Complications

Cataract and glaucoma are the main complications of viral anterior uveitis requiring appropriate management.³ Without prompt treatment, cytomegalovirus anterior uveitis may progress to glaucoma, making early diagnosis critical to prognosis.⁴ Additional complications include:

• Posterior synechiae: Adhesions between iris and lens that can lead to pupillary block
• Chronic elevation of intraocular pressure: Particularly in viral etiologies and chronic inflammation
• Vision loss: From complications including glaucoma, cataract, or macular edema
• Iris atrophy: Particularly in viral anterior uveitis⁵
• Corneal decompensation: In cases with significant endothelial involvement
• Hypotony: In chronic cases with ciliary body damage
• Corticosteroid-related complications: Including steroid-induced glaucoma and cataract from prolonged topical or systemic therapy

Clinical Pearls

• Anterior uveitis is the most common anatomical form of uveitis¹
• Clinical characterization of unilateral versus bilateral disease and granulomatous versus nongranulomatous features is the main step in etiologic diagnosis^1,2
• Viral anterior uveitis should be suspected when anterior uveitis is associated with elevated intraocular pressure, corneal involvement, and iris atrophic changes⁵
• Fine, diffuse, stellate keratic precipitates suggest viral etiology³
• The priority is ruling out infection before starting corticosteroid therapy²
• Improvements in molecular diagnostics have revealed viral causes in many cases previously classified as idiopathic³
• Chest radiography and serologic testing for syphilis, HLA-B27, and angiotensin-converting enzyme are appropriate for severe, bilateral, recurrent, or chronic cases⁶
• Early antiviral treatment in cytomegalovirus anterior uveitis reduces the risk of requiring glaucoma surgery⁴
• Biologics have transformed management of HLA-B27-associated and juvenile idiopathic arthritis-associated anterior uveitis¹

Common Pitfalls

• Initiating corticosteroids before ruling out infectious etiologies, particularly syphilis and viral causes, which can worsen outcomes²
• Ordering extensive laboratory workup without clinical orientation, which is of limited utility and incurs significant costs⁶
• Failing to examine the posterior segment, missing masquerade syndromes or posterior involvement¹
• Not recognizing viral anterior uveitis due to overlapping features with noninfectious hypertensive anterior uveitis syndromes³
• Inadequate duration of antiviral therapy for cytomegalovirus anterior uveitis, leading to high relapse rates³
• Delaying referral to uveitis specialist when conventional immunomodulatory therapy fails to achieve disease control⁶
• Missing elevated intraocular pressure in viral anterior uveitis, allowing progression to glaucoma⁴
• Assuming all anterior uveitis requires the same workup, rather than tailoring investigations to clinical presentation, severity, and pattern⁶