Late-onset refractive shift after small-aperture corneal inlay implantation

We present a series of 5 consecutive cases in which a small-aperture corneal inlay (Kamra ACI7000PDT) was uneventfully implanted in a corneal pocket created at a depth between 200 μm and 250 μm. Three months after surgery, all patients had good visual results, normal corneal surfaces, and adequate stromal healing. Between 6 months and 19 months after surgery, visually significant refractive changes appeared in the form of a hyperopic shift in 4 cases and a myopic shift in 1 case. Topical steroids were ineffective. In 2 cases, the inlay was explanted. Among the adverse events reported in the 2015 approval of the small-aperture corneal inlay was a low incidence of late refractive changes. Recently, we have encountered a relatively higher frequency of these adverse events. Thus, we evaluated the hypothesis that a relationship between these late refractive changes and the decreased diffusivity of nutritional fluid to the anterior stroma accentuated by a lower depth of implantation is the cause.