Keratoprosthesis with biocolonizable microporous fluorocarbon haptic. Preliminary results in a 24-patient study

Abstract

Background: Most complications of a keratoprosthesis occur at the tissue-to-implant interface. The ideal prosthesis would eliminate this interface by having the tissue actually grow into the supporting material. We present a prospective clinical human study of a novel biocolonizable keratoprosthesis in 24 eyes of 24 patients.

Design: To promote implant stability, the 9-mm-diameter haptic was fashioned using a custom-made microporous fluorocarbon with a 4-mm-diameter, 2.67-mm-long, central optic made of medical grade polymethylmethacrylate, giving a global visual field of 110 degrees to 130 degrees. Only bilaterally blind patients with untreatable corneal diseases were included in the study. The haptic was inserted into a lamellar pocket delaminated in the stroma, and the optic was positioned through a hole trephined in the central cornea.

Results: The average follow-up was 15.7 months (range, 4 to 28 months). The host corneal fibroblasts penetrated and proliferated into the peripheral microporous fluorocarbon and provided anchorage between the cornea and prosthesis. Seventeen patients (70.8%) had visual acuity improvements. Mean corrected final visual acuity was 20/100 (range, 20/30 to 20/400). Five anatomic failures occurred in the first 6 months (three extrusions, one dislocation of the optic, and one endophthalmitis). We had one case (4.1%) of treatable glaucoma. We successfully removed four of five retroprosthetic membranes that had occurred. No retinal detachment occurred.

Conclusion: The biocompatible inert microporous polymer did not eliminate all mechanical complications associated with a keratoprosthesis.