The Boston Keratoprosthesis in severe ocular trauma

Background: In eyes with corneal disease and opacity so severe that standard corneal transplantation carries a poor prognosis, a keratoprosthesis (KPro) may still be successful in providing functional visual acuity. The purpose of this study was to determine the outcome of Boston KPro implantation in the rehabilitation of severe ocular trauma. Methods: This is a retrospective study of 30 eyes (30 patients) with severe ocular trauma that underwent Boston KPro type 1 implantation at the Massachusetts Eye and Ear Infirmary. Of these 30 eyes, 6 had mechanical trauma, 21 had chemical burns, and 3 had thermal burns. The measures used in this review are 5-fold: (i) anatomic success; (ii) number of postoperative repair procedures performed; (iii) preoperative and postoperative visual acuity; (iv) number of eyes with concomitant preoperative retinal or optic nerve damage prior to KPro surgery; and (v) incidence of postoperative complications. Results: Preoperative visual acuity ranged from counting fingers to light perception (median: hand motion). Best-corrected postoperative visual acuity ranged from 20/20 to no light perception (median: 20/80). Anatomic success was achieved in 5 out of 5 mechanically traumatized eyes, 14 out of 17 eyes with chemical burns, and 3 out of 3 eyes with thermal burns. Repair procedures were done in 8 of the 17 chemically burned eyes. The number of eyes with concomitant preoperative ocular disease was 2 out of 6 in the mechanical trauma group, 10 out of 21 in the chemical burn group, and 1 out of 3 in the thermal burn group. The incidence of postoperative complications was greater in the chemical burn group than in either the mechanical trauma or the thermal burn group. Interpretation: The Boston KPro, can provide considerable visual improvement and a long-term anatomic retention rate in severely traumatized eyes. The overwhelming danger in severe chemical burns is glaucoma progression despite a functioning tube implant and normal intraocular pressure.