Refractive Use of Intrastromal Corneal Rings in Penetrating Keratoplasty

Intrascleral ring implants appeared in the 1950s with the aim of altering the curvature of the cornea promoting thecorrection of refractive errors. More recently, corneal rings have become more important in ophthalmology for theremodeling of irregular corneas, in which the excimer laser would be contraindicated.Corneal transplants have several indications and currently have a wide range of options depending on theunderlying pathology. The postoperative management of keratoplasty, especially regarding refractive errors,can be very difficult. Some situations, such as anisometropia and intolerance of contact lenses, require surgicalprocedures for visual rehabilitation.Among the surgical option have the procedures with use the excimer laser, when the biomechanical conditions ofthe cornea allow, and in specific cases of contraindication the possibility of using the intrastromal ring implants,or even implants of intraocular lenses (phakic or pseudophakic).In 2011, the studies were started using large arc length segments with very positive results. They have numerousadvantages among them the maintenance of every implant in a single plane allowing greater regularity of thesurface of the cornea and with the advent of femtosecond laser the implant of these segments became possible.The option of a ring implant is based on the fact that the procedure has the possibility of being reversible withoutcorneal consumption.Keratoplasty is aimed at obtaining the visual rehabilitation of the patients, so the simple fact of obtaining a goodtransparency of the corneal button can not be considered as success, therefore the final visual acuity should alwaysgive the final word on the result.