Aachen keratoprosthesis as temporary implant for combined vitreoretinal surgery and keratoplasty: report on 10 clinical applications

A new keratoprosthesis was used during pars plana vitrectomy in order to te st the optical quality, watertightness, short-term biocompatibility and han dling of the new device. The implantability was also tested, given that thi s kerato-prosthesis might in future be left in place for several months. Th is Aachen keratoprosthesis (Aachen-KPro) is developed to be used as permane nt implant to restore vision in corneal blind patients. Patient and methods: The Aachen-KPro was used during pars plana vitrectomy in 10 patients with opaque corneas. In four cases, trauma precipitated the ocular disease. Eye burn was the cause of corneal and retinal disorders in another four cases. One patient had a history of congenital glaucoma with m yopia, and one of uveitis with corneal dystrophy. After trephination of 6.5 mm in diameter, the Aachen-KPro, composed of soft silicone rubber, was tem porarily placed in the trephination hole. After completion of the vitrectom y. the Aachen-KPro was replaced by a 7 mm corneal graft. Results: Intraoperative use of the Aachen-KPro allowed uncomplicated intrao perative handling, smooth adaptation to the corneal rim in the trephination hole, and an undistorted view of the central and peripheral retina. Leakag e, even during scleral depression, could be avoided by individual suturing of the scleral rim. After a follow-up period of 1-10 months, the retina was still attached in all cases. The corneal graft was clear after surgery in four eyes, and edema was found in three cases. Amnion or conjunctiva was pl aced over three patients' transplants. Conclusion: We report the first temporary implantations of a new keratopros thesis in 10 patients. Its flexibility and good optical qualities allowed c ontrol of intraoperative procedures. The outcome and prognosis of the vitre oretinal surgery and keratoplasty were related to the primary diagnosis. Th e Aachen-KPro has shown advantages, especially in eyes when the anterior ey e segment is severely damaged by eye burn or previous surgical intervention s. In the future, prolonged use of the Aachen-KPro is planned for selected eyes.