Prolonged ocular hypotension: would ciliary tissue transplantation help.

AIMS: Ocular hypotony and phthisis bulbi from persistent fistulae, ciliochoridal detachments, or inflammation, that cannot be treated currently. However, complete shutdown of the ciliary epithelium is rare. Secreting, transplanted ciliary tissue could restore the IOP to a level where further visual damage would not occur or even be reversed. METHODS: Allografts of ciliary epithelium and its substrate were placed on to the surface of the iris of normal albino rabbits. The progress of the transplanted tissue was followed in the untreated animals, those who had been immunosuppressed and those who had been immunosuppresed together with cold whole body perfusion for up to 55 days. Changes were assessed by slit-lamp observation, luconyl blue staining, fluoresceine angiography, and these were compared with the histology and electron microscopic appearances. RESULTS: Transplants survived the period of ischaemia in the anterior chamber. They started to be revascularised within 4 days and were completely revascularised in 12 days. Untreated animals showed classical rejection phenomena. However, the ciliary epithelial tissue in those animals who were immunosuppressed and had been subjected to whole body perfusion remained normal and were secreting aqueous, as judged by the histological and electron microscopic appearances. CONCLUSIONS: Perfused allografts of ciliary tissue will survive in the normal anterior chamber of the immunosuppressed rabbit, and the electron microscopic evidence indicates that the tissue is producing aqueous. If this can be shown to be adequate in the damaged eye, then ciliary transplantation could be a valuable tool in the management of severe intractable hypotony.

Ciliary tissue transplantation in the rabbit.

Irreversible damage of the ciliary body can be responsible for prolonged ocular hypotony and phthisis bulbi, which, currently, cannot be treated. The aim of this study was to achieve survival of morphologically normal ciliary tissue (CT) transplants in the anterior chamber of a rabbit's eye. Outbred female New Zealand albino rabbits received CT allografts, which were placed on to the surface of the host iris. We evaluated the influence of ciclosporin (CsA), VEGF and donor perfusion on graft survival. Operated eyes were assessed clinically and histologically, and revascularization of the grafts was determined by fluorescein angiography. All grafts became dark and ischemic during the first five to seven days after transplantation. Reperfusion of the grafted tissue was complete at approximately ten days after transplantation. In untreated animals, transplants became infiltrated by inflammatory cells, which led to destruction of the tissue. This was prevented by systemic use of CsA. Transplants treated with VEGF prior to transplantation had fewer ischemic areas but epithelial cell survival was not improved. Whole body donor perfusion prior to preparation of the grafts resulted in less inflammation and, histologically, in a better quantity and quality of the epithelial cells in the CT transplants. Ciliary tissue can be successfully transplanted but the ciliary epithelium suffers from ischemia and in untreated animals the whole transplant is rejected in the classical fashion. If the donor is perfused and the host immunosuppressed, histologically normal ciliary epithelium can be preserved together with rapid revascularization, minimal inflammation and good survival of the transplant, although fibrosis continued to occur during the two months after transplantation.