Eye

Cornea

Nonspecific responses-cornea



Topic Completed: 1 October 2013

Minor changes: 21 April 2021

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PubMed Search: Nonspecific responses in cornea

Nat Pernick, M.D.
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Cite this page: Pernick N. Nonspecific responses-cornea. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/eyecorneanonspecific.html. Accessed December 6th, 2021.
Definition / general
  • Corneal edema may lead to intraepithelial vesicles and bullae between epithelium and Bowman layer
  • Aberrant basal lamina may develop within corneal epithelium in response to some injuries
  • Collagenous tissue (pannus) may accumulate between corneal epithelium and Bowman layer
  • Blood vessels may be present in superficial or deep stroma after inflammatory conditions (normally cornea is avascular)
  • Irregular thickening of Descemet membrane occurs with aging
Blood staining
  • Due to chronic anterior chamber hemorrhage or hyphema, caused by trauma or increased intraocular pressure
  • Hemoglobin and other red blood cell breakdown products may diffuse into and stain cornea
  • May eventually clear, beginning in periphery
  • Microscopic (histologic) description: small pink-brown globules or spheres in corneal lamellae
Epithelial ingrowth
  • Occurs after penetrating corneal injury (trauma, surgery)
  • Epibulbar squamous epithelium grows through wound into anterior chamber of eye and may replace corneal epithelium and cause bullous keratopathy
  • May cause intractable glaucoma if epithelium invades trabecular meshwork
  • Microscopic (histologic) description: squamous epithelium in cornea instead of single layered corneal epithelium
  • Positive stains: keratin
Pannus
  • Due to chronic inflammation in eye
  • Microscopic (histologic) description: proliferation of fibrovascular tissue under epithelium in anterior cornea
Ulceration
  • Due to any process that causes uneven distribution of the tear film across cornea
  • Bacterial ulcers often destroy epithelium and Bowman layer with variable stromal destruction; due to Staphylococcus aureus, Streptococcus pneumoniae, E. coli, Klebsiella, Pseudomonas
  • Complications include corneal perforation and scarring
  • Fungal ulcers occur 8 - 15 days after trauma, usually involving vegetative matter; due to Candida, Aspergillus, Cephalosporium, Fusarium
  • Satellite lesions are also present
  • Rarely due to ocular cicatricial pemphigoid (Eur J Ophthalmol 2007;17:121)
  • Case reports: 47 year old man with Exserohilum longirostratum (dematiaceous fungus) after trauma (Am J Clin Pathol 1994;101:452)
  • Microscopic (histologic) description: eosinophils and granulomas with fungal infection
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