The image shows a large ring ulcer, typically described in Acanthamoeba keratitis, associated with contact lens users.
- Commonly seen in contact lens wearers ( if tap water is used to clean lens).
- Immunocompromised individuals.
- Following trauma.
- Acquired from the swimming pool.
- Typical reticular pattern.
- Radial keratoiritis-perineural infiltrates seen during the first 4 weeks-Pathognomonic sign.
- Pseudodendrites-mistaken with herpes simplex keratitis.
- Severe cases may have a central or paracentral ring-shaped lesion (Ring abscess) and hypopyon.
o Staining: Calcofluor white, acridine orange, lactophenol blue.
o Culture: Non-nutrient agar with Escherichia coli overlay.