Clinical Pearl by: Yuliya Bababekova, SUNY 2013
In order to differentiate between sterile versus infectious keratitis, look for several important distinctions.
- Sterile infiltrates are located in the periphery.
- These are typically small, grey lesions that are separated from the limbus by about 1 mm of clear space.
- Immune cells are thought to be more readily available because of the location of capillaries in the peripheral cornea.
- Infectious infiltrates are located in the central region of the cornea.
- Clinical signs of infectious infiltrates include fluorescein staining, and raised appearance with a surrounding haze.
Symptoms are also very different:
- Pts with sterile infiltrates are mildly symptomatic
- Those with infectious keratitis are often photophobic and in pain.
Note: When examining these patients, it’s important to consider that sub-epithelial infiltrates are a distinguishing feature of EKC (epidemic keratoconjunctivitis).