A case of extreme mushroom keratoplasty: Rationale and long-term follow-up

Full-thickness keratoplasties remain fraught with wound healing and optical problems. We report an enhanced mushroom keratoplasty technique, which maintains a wide anterior optical component of the graft and a smaller internal graft diameter, maximizing preserved host endothelium and graft host junction area. A comparative mathematical modeling of spherical caps and cylindrical areas were calculated for traditional, mushroom, and extreme mushroom keratoplasty techniques. An index case was identified, and its long-term follow-up was reviewed. Greater anterior-posterior trephination disparities provide a refractive advantage while increasing graft host junction and retained host endothelium areas. A case of traumatic, full-thickness axial corneal scarring treated with an extreme mushroom, penetrating keratoplasty had an acute graft rejection at 1 month and failed. Over 18 months, the cornea cleared, and clarity remains at 10 years (and counting). Increased contact area for stromal healing and retention of host endothelial reserve are maximized in extreme mushroom keratoplasty. A representative case demonstrates excellent optical performance without irregular astigmatism and the ability for residual host endothelium to clear a failed graft and has sustained long-term clarity after that.