PRESENT STATUS OF PROSTHOKERATOPLASTY

We have tried to present in chronological order a description of our work in prosthokeratoplasty, including Cardona's original experimental studies and the clinical trials, conducted over the past 10 years, with the different model keratoprostheses. Our steady progress toward the control of the complications that lead to extrusion of the implant, rather than an accidental breakthrough, has been the result of careful evaluation of our failures. That this has led to improvements in the implant and surgical techniques, which seem to make this procedure no longer an experimental one but a valuable clinical contribution, is borne out by the dozens of patients who have benefited from the operation, some of them with almost 10 years of permanent visual improvement. The buried implant and surgical techniques for its insertion have been abandoned. Only the penetrating keratoprostheses are being used at present, principally the through-and-through implant with a perforated interlamellar plate, a fenestrated interlamellar plate or a siliconized Teflon meshwork supporting skirt. These three improved implants, with a threaded optical cylinder attached to the interlamellar plate, permit adjustment of the surface to the level of the surrounding host tissue, thus inhibiting growth of tissue over the implant. The surgical techniques that seem to offer prolonged, or even permanent, visual rehabilitation are the original Cardona pocket technique and the technique in which the keratoprosthesis is supported either by a total fullthickness corneal graft or by sclera plus conjunctiva or by a buccal mucosa graft. The new nut-and-bolt transcorneal keratoprosthesis seems promising but it is still under clinical evaluation. We feel that the strides made in this field in the past decade are sufficient to justify its clinical application, but that the work, both experimental and clinical, should be continued in an effort to perfect still further the implants and techniques of prosthokeratoplasty in order to increase the success rate in those eyes that cannot be improved by any other type of corneal surgery. © 1969.