Staphyloma

Staphyloma - Scleral Bulge Basics

• Definition: A localized, outward bulging of the outer sclera, which is thinned and lined by uveal tissue.
• Primary Cause: Underlying weakness of the sclera, often secondary to inflammation, injury, or progressive high myopia.

⭐ Staphyloma implies ectasia of the sclera with uveal tissue incarceration.

Etiopathogenesis - Weak Wall Origins

• Origins of Scleral Weakness:
  • Congenital: Defective scleral development.
  • Acquired:
    • Inflammation: Severe scleritis (esp. necrotizing), endophthalmitis.
    • Trauma: Penetrating injuries.
    • Surgery: Complications from glaucoma surgery, pterygium excision (esp. with mitomycin C).
    • Degenerative: Pathological high myopia causing scleral stretching and thinning.
    • Sustained ↑IOP: Uncontrolled glaucoma (e.g., absolute glaucoma) exerting pressure.
• Mechanism: Progressive scleral thinning and weakening, combined with or worsened by ↑IOP, results in scleral ectasia (outward bulging) lined by prolapsed uveal tissue.

⭐ Necrotizing scleritis is a common cause of anterior staphyloma.

Classification - Mapping the Bulge

📌 AICE-P: Anterior, Intercalary, Ciliary, Equatorial, Posterior.

⭐ Posterior staphyloma is a hallmark of pathological myopia.

Clinical Features & Diagnosis - Eye Spy Swelling

• Symptoms:
  • Decreased vision (often progressive, can be sudden)
  • Ocular pain, discomfort, or photophobia
  • Cosmetic blemish from the noticeable bulge
• Signs:
  • Characteristic bulge: Bluish/dark coloration due to underlying uveal tissue visible through thinned sclera.
  • Scleral thinning: Palpable or visible thinning at the staphyloma site.
  • Transillumination: Positive - light transmits easily through the ectatic area.

    ⭐ Transillumination is a key clinical sign for staphyloma, indicating significant scleral thinning with uveal tissue involvement.

• Investigations:
  • Slit-lamp biomicroscopy: Essential for detailed examination of anterior staphylomas.
  • Indirect Ophthalmoscopy: To visualize and assess posterior staphylomas.
  • B-scan ultrasonography: Confirms posterior staphyloma; shows characteristic scleral excavation and uveal tissue lining.
  • OCT (Optical Coherence Tomography): Provides detailed cross-sectional images, delineating tissue layers.

Management & Complications - Patch & Protect

• Management

  • Conservative: Treat underlying cause (e.g., scleritis), lubrication, protective eyewear.
  • Medical: Intraocular pressure (IOP) control (e.g., beta-blockers, carbonic anhydrase inhibitors) if glaucoma is a risk or present.
  • Surgical: Scleral reinforcement graft (fascia lata, donor sclera, pericardium) for impending/actual perforation or rapid progression.

    ⭐ Scleral reinforcement is indicated for rapidly progressing staphylomas or those at high risk of perforation.

• Complications

  • Progressive myopia & astigmatism
  • Amblyopia (especially in children)
  • Retinal detachment
  • Secondary glaucoma
  • Spontaneous perforation
  • Visual loss

High‑Yield Points - ⚡ Biggest Takeaways

• Staphyloma: An ectasia of thinned sclera lined by uveal tissue, from weakened scleral resistance.
• Posterior staphyloma is a hallmark of pathological myopia, located at the posterior pole.
• Anterior staphyloma involves the cornea, often after corneal perforation with iris involvement.
• Other types by location: Intercalary (limbus), Ciliary (over ciliary body), Equatorial (at equator).
• Presents as a dark, bluish-black bulge due to underlying pigmented uvea visible through thinned sclera.
• Key Complications: High astigmatism, secondary glaucoma, retinal detachment (especially posterior type).