Eye
Cornea
Nonspecific responses-cornea
Author: Nat Pernick, M.D.
Last author update: 1 October 2013
Last staff update: 21 April 2021
Copyright: 2004-2024, PathologyOutlines.com, Inc.
PubMed Search: Nonspecific responses in cornea
Cite this page: Pernick N. Nonspecific responses-cornea. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/eyecorneanonspecific.html. Accessed April 20th, 2024.
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
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
