Nummular (coin-like) Keratitis/ Scars
● Feature of viral keratoconjunctivitis, commonly Adenoviral (Epidemic Keratoconjunctivitis/EKC)
● Other causes: HSV, HZO, Brucellosis, Acanthamoeba, Lyme disease, EBV, Adult inclusion conjunctivitis
● It is a corneal sign, not diagnosis
● Subepithelial infiltrates (SEI), can also be anterior stromal
● Can be unilateral/bilateral
● Tiny granular deposits surrounded by a stromal haze in infective stage
● After healing, nummular scars remain
● Precedes disciform keratitis
● SEI represent host immune response to presence of viral antigens in superficial stroma, reaching diffusion during the epithelial infection stage
Treatment in cases of EKC:
● Steroids use may increase adenoviral replication→ viral diffusion into anterior stroma
● Steroids avoided in initial management of EKC to decrease occurrence of SEI
● But untreated SEIs, with increased accumulation of immune cells and mediators in the anterior stroma, can result in the destruction of corneal collagen and stromal scarring → So, steroid use should be considered when appropriate to protect corneal clarity
● Indications for steroid use:
1. Central SEI affecting vision
2. Occupation requirements for lear vision
3. Confluence of SEI with overlap of adjacent spots
● Peripheral lesions can be observed → clear as the immune defense removes the viral antigen → 3 episodes occur at 6-8 weeks, 3-4 months, 9-12 months and then the episodes becomes shorter and less severe ● Commonly used steroids: Lotepredonal or FML, Severe cases: Dexamethasone
● Topical cyclosporine A or Tacrolimus ointment can be added to reduce recurrence rate
Other treatment options:
● Established SEI: Surface ablation
● Scars: Rigid contact lens/ Superficial anterior lamellar keratectomy
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