Interface keratitis following endothelial keratoplasty

Infectious interface keratitis (IIK) is an uncommon but potentially vision-threatening complication following posterior lamellar keratoplasty, including Descemet stripping automated endothelial keratoplasty (EK) and Descemet membrane EK. The interface space allows microbial sequestration, limits antimicrobial penetration, and complicates microbiologic diagnosis. This review summarizes epidemiology, microbiology, clinical presentation, management strategies, and outcomes of IIK after EK, with an emphasis on surgical decision-making. Across reviews and case series, Candida remains the predominant organism causing IIK after EK. In certain cases, selected localized infections may be considered as graft-sparing candidates for interface drainage and/or directed intrastromal antimicrobial therapy. While others - particularly fungal and atypical infections - require escalation to repeat keratoplasty or therapeutic penetrating keratoplasty (TPK). IIK following EK should be approached as a deep-seated infection in an anatomically secluded space. When clinical progression is observed or diagnosis remains uncertain, early intervention and timely "source control" are central to management. Targeted intrastromal and/or interface therapy may preserve the original EK graft in carefully selected cases, whereas TPK remains the most definitive approach, especially for progressive or medically refractory infection.