Diseases of the uvea

The uvea is the middle layer of the eye and consists of three parts: iris, ciliary body, and choroid (see also eye and orbit). There are four types of uveitis: anterior, posterior, complete (panuveitis), and intermediate, the latter being the least common. Uveitis is significant because of its association with systemic inflammatory conditions such as sarcoidosis, seronegative spondyloarthropathies, and vasculitides. However, infectious causes such as brucellosis, leptospirosis, and Lyme disease are also possible. Anterior uveitis manifests with periocular pain, ocular hyperemia (“red eye”), and photophobia. Posterior uveitis manifests with painless visual disturbances such as floaters and decreased visual acuity. Initial treatment for uveitis includes topical glucocorticoids and cycloplegics. If infection is suspected, an antibiotic or antiviral is used prior to topical glucocorticoids. Complications of uveitis include secondary glaucoma, cataract, posterior synechiae, and vision loss.

Other disorders of the uvea covered in this article are neovascularization of the iris, benign and malignant uveal tumors, iridodialysis, iridodonesis, and heterochromia.

• Definition: inflammation of the uvea (anterior, intermediate, posterior, and complete )

• Subtype: intermediate uveitis
  • Definition: inflammation of the vitreous body (vitritis)
  • Etiology and clinical features: see “Posterior uveitis”
  • Diagnostics
    • Slit-lamp examination: absent or very weak irritation of the anterior chamber
    • Ophthalmoscopy
      • Vitritis with numerous cells in the vitreous body (spherical or star-shaped bodies)
      • Often posterior vitreous detachment
      • Possibly vasculitis
      • Possibly macular edema
• Treatment
  • Initial treatment
    • Glucocorticoids
      • Topical route in anterior uveitis
      • Periocular or intraocular route in posterior uveitis
    • Cycloplegics (e.g., atropine, scopolamine)
    • Analgesics (e.g., NSAIDs)
    • Close followup examinations
  • Infectious uveitis: antibiotic or antiviral therapy
  • Severe cases or those resistant to initial treatment
    • Systemic glucocorticoids
    • Immunosuppressants (e.g., azathioprine, cyclosporin, infliximab)

Uveitis is often associated with HLA-B27 syndromes, such as Crohn disease, ulcerative colitis, ankylosing spondylitis, psoriatic arthritis, juvenile idiopathic arthritis, and reactive arthritis.

Posterior uveitis does not manifest with pain (unlike painful anterior uveitis), because the choroid is not innervated by sensory nerves.

References:^[1][2][3]

• Definition: pathological neovascularization of the iris
• Etiology
  • Vascular hypoxia (e.g., central retinal vein occlusion, central retinal artery occlusion, temporal arteritis)
  • Neural diseases (e.g., diabetic retinopathy)
  • Inflammatory (e.g., chronic uveitis)
  • Neoplasms of the eye (e.g., uveal melanoma)
• Pathophysiology: : chronic ischemia of the retina → release of vasoproliferative substances; , such as VEGF, which also affect the anterior segment of the eye → neovascularization of the iris
• Clinical features: initially asymptomatic; symptoms arise following complications of the condition (see below)
• Treatment
  • Goal: reduce ischemic impetuous for neovascularization
  • Laser treatment: panretinal photocoagulation: Risks associated with laser treatment include night vision impairment, visual field loss, and/or further fibrosis of the vitreous body with risk of retinal detachment.
  • VEGF inhibitors
• Complications
  • Anterior chamber hemorrhage (hyphema)
  • Progressive neovascular glaucoma: displacement of the chamber angle due to newly formed vessels → secondary angle-closure glaucoma → complications, including decreased visual acuity

References:^[4][5]

Benign tumors

• Choroidal nevus: benign melanocytic lesion (nevus) of the posterior uvea
  • Epidemiology: common ^[6]
  • Fundoscopic appearance
    • Flat or slightly elevated
    • Gray-yellow in color
    • Clearly defined margins
    • Remains stable in size over time
  • Treatment
    • No treatment necessary
    • Regular monitoring is important as malignant transformation is possible, though rare.

Malignant tumors

• Uveal melanoma: most common primary intraocular malignancy ^[7]
• Uveal metastasis
  • Epidemiology
    • Most common intraocular malignancy in adults
    • Primary cancers most commonly leading to uveal metastasis: breast cancer and lung cancer
  • Fundoscopy
    • Elevated edges
    • Gray-yellow in color
    • Indiscrete margins, irregular shape
    • Grows over time
    • Signs of serous retinal detachment

Iridodialysis

• Definition: separation of the iris from the ciliary body
• Etiology: blunt trauma to the eye
• Clinical features
  • Diplopia
  • Photophobia
  • Glare symptoms
  • Other signs and symptoms of blunt trauma to the eye (e.g., anterior chamber hemorrhage, secondary glaucoma, vision loss)
• Diagnostics ^[8]
  • Slit-lamp examination
    • Irregular pupil
    • In cases of large iridodialysis: double pupil
  • Ophthalmoscopy to exclude further traumatic bulb injuries
• Treatment ^[9]
  • Observation, bed rest
  • Topical cycloplegics (e.g., atropine, scopolamine) and glucocorticoids
  • In cases of anterior chamber hemorrhage: anterior chamber washout
  • If diplopia or other visual disturbances persist: surgical repair

Iridodonesis ^[10]

• Definition: vibration or tremulous movement of the iris elicited by eye movement
• Etiology: aphakia (i.e., absent lens of the eye), ectopia lentis

Heterochromia iridum

• Definition: irises of different color
• Types
  • Congenital heterochromia
  • Acquired heterochromia
    • Injury or infection
    • Horner syndrome
    • Glaucoma
    • Fuchs heterochromic iridocyclitis: a chronic low-grade inflammatory disease of the eye characterized by heterochromia and ciliary fibrosis.
    • Sympathetic heterochromia
    • Ocular melanosis

Vogt-Koyanagi-Harada disease ^[11][12]

• Definition: a rare systemic condition characterized by a rapid loss of vision, alopecia, vitiligo, poliosis, and neurological symptoms (e.g., vertigo, drowsiness)
• Epidemiology
  • Peak onset between 30–40 years of age ^[11]
  • Most common in southeast Asian and Hispanic populations
• Etiology: The exact cause is unknown.
• Pathophysiology: thought to involve an autoimmune response to antigens associated with retinal pigment epithelium, melanin, and melanocytes ^[12]
• Clinical features: manifests in 4 distinct stages
  1. Prodromal stage: unspecific, flu-like symptoms (e.g., headache, fever, dizziness, eye pain) for 3–5 days
  2. Acute uveitic stage: blurred vision that initially affects only one eye, but progresses to the second eye within 2 weeks
  3. Chronic stage: vitiligo, poliosis, and choroid depigmentation.
  4. Recurrent stage: panuveitis
• Diagnostics ^[13]
  • Primary diagnosis is based on clinical features and characteristic fundoscopy findings
    • Uveitic stage: posterior uveitis with multiple serous retinal detachments → panuveitis
    • Chronic stage: sunset-glow fundus (orange-red discoloration of the choroid due to inflammatory depigmentation).
    • Recurrent stage: panuveitis with acute exacerbations of anterior uveitis and iris nodules
  • Additional tests (e.g., optical coherence tomography, fundus fluorescein angiography, electroretinography) may be indicated if findings are inconclusive or to assess treatment efficiency
• Treatment
  • Acute phase: high dose corticosteroids (e.g., IV methylprednisolone)
  • Maintenance: oral corticosteroids for at least 6 months OR immunosuppressants (e.g., azathioprine, cyclosporine A)
• Complications: secondary cataracts, glaucoma, and/or subretinal neovascularization (potentially loss of vision)
• Prognosis: Visual acuity can be preserved when the condition is diagnosed early and treated aggressively.