Introduction to Keratoconus and the Need for Doughnut Refractive Lenticule Transplantation

Keratoconus is a progressive, noninflammatory ectatic disorder of the cornea marked by localized stromal thinning, biomechanical weakening, and anterior/posterior ectasia of the corneal surface. This conical deformation leads to significant optical aberrations, including irregular astigmatism, progressive myopia, and reduced best-corrected visual acuity (BCVA) [1]. The condition typically presents in the second decade of life and progresses over several years before stabilizing in the third or fourth decade [2].