Keratoprosthesis. I. Results obtained after implantation of 12 one-piece prostheses. A retrospective, follow-up study

In Vivo Evaluation of a Collagen Corneal Allograft Derived From Rabbit Dermis

BACKGROUND

This study evaluates epithelialization, clarity, intraocular inflammation, and fibroblast ingrowth of a collagen corneal allograft derived from rabbit dermis.

METHODS

Dermal collagen fibers were dispersed intact and chemically modified to make them soluble. The allografts consisted of a fibrous, opaque peripheral zone and a central clear area. Twelve New Zealand white rabbits underwent penetrating keratoplasty with implantation of an allograft. The grafts were evaluated daily for clarify, anterior segment inflammation, and extent of reepithelialization with a slit-lamp microscope.

RESULTS

Epithelialization of the fibrous peripheral zone of the graft ranged from 0% to 90%. The central clear area did not epithelialize in any of the animals. Fibroblasts migrated into the peripheral zone in all eyes. Complications included ulceration of the central clear area in two eyes. There was no ulceration or leakage at the graft-host interface and no synechia, fibrous, or inflammatory retrocorneal membranes in any of the eyes.

CONCLUSIONS

Our study is the first to describe the method of modifying dermal type I collagen into a clear corneal allograft. Survival of the corneal collagen allograft beyond 1 month may be limited by several factors including lack of epithelialization of the central clear area.

Keratoprosthesis. II. Results obtained after implantation of 27 dismountable two-piece prostheses. A retrospective, follow-up study

During the years 1974-1987 a total of 27 two-piece keratoprostheses were implanted in 25 eyes of 22 different patients with bilateral blinding anterior segment disease with no possibility for a successful corneal transplantation. The prosthesis design and the surgical procedures used are described. The healing in and fixation of the prostheses were initially good in all cases, but 9 prostheses were lost or removed because of complications during the postoperative period of observation. The prosthesis retention time was significantly longer than that earlier achieved by the use of a one-piece prosthesis. In 18 of 27 cases a visual acuity of 6/60 or better was obtained. Postoperative complications included necrosis of the tissues covering and supporting the prosthesis, infection around the prosthesis, overgrowth of the surrounding tissues and the development of dense retroprosthetic membranes. Despite the obvious risks, keratoprosthesis surgery in a small number of patients with severe corneal disease represents the only potential hope for a visual rehabilitation, and should therefore be considered.