Biologic Keratoprosthesis Materials

摘要

The keratoprosthesis (KPro; "artificial cornea") offers patients with cornea blindness, the hope of visual recovery. The first KPro designs entailed placing an optically clear material through an opaque cornea. Although introduced over 200 years ago, the basic concept is retained in many of the modern KPro designs. The Boston KPro, employs a polymethylmethacrylate (PMMA) (inert plastic) optic stabilized between a front and back plate. With over 2000 implanted world-wide to date, the Boston KPro has an excellent retention rate in patients who have failed prior penetrating keratoplasties, but lack chemical injuries or autoimmune cicatricial diseases, such as Stevens-Johnson syndrome or pemphigoid. From the Boston KPro multicenter study, the patient population who had a primary diagnosis of graft rejection retained the KPro in 97% of the eyes with a mean follow-up of 8.5 months.1 However, patients with cicatricial autoimmune disease had a retention rate of 83% and those with chemical injuries as a primary diagnosis had an 89% retention rate. Over a longer follow-up period, the retention rate decreases further for patients with autoimmune diseases and chemical injuries.2,3 For this subset of desperate patients, we continue to search for methods of increasing the retention rate of a KPro.