A new keratoprosthesis was used during pars plana vitrectomy in order to test the optical quality, watertightness, short-term biocompatibility and handling of the new device. The implantability was also tested, given that this keratoprosthesis might in future be left in place for several months. This Aachen keratoprosthesis (Aachen-KPro) is developed to be used as permanent 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 myopia, and one of uveitis with corneal dystrophy. After trephination of 6.5 mm in diameter, the Aachen-KPro, composed of soft silicone rubber, was temporarily placed in the trephination hole. After completion of the vitrectomy, the Aachen-KPro was replaced by a 7 mm corneal graft.
Results: Intraoperative use of the Aachen-KPro allowed uncomplicated intraoperative handling, smooth adaptation to the corneal rim in the trephination hole, and an undistorted view of the central and peripheral retina. Leakage, 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 placed over three patients' transplants.
Conclusion: We report the first temporary implantations of a new keratoprosthesis in 10 patients. Its flexibility and good optical qualities allowed control of intraoperative procedures. The outcome and prognosis of the vitreoretinal surgery and keratoplasty were related to the primary diagnosis. The Aachen-KPro has shown advantages, especially in eyes where the anterior eye segment is severely damaged by eye burn or previous surgical interventions. In the future, prolonged use of the Aa-chen-KPro is planned for selected eyes.