The ciliary body and the iris in experimental uveitis in rabbits. A scanning electron microscopic study.

Acute anterior immunogenic uveitis of varying degree was induced in rabbits by the injection of human serum albumin into the vitreous body. After fixation and drying by the critical point method, the lens, the zonules, the vitreous and, in some specimens, coagulated exudate were removed by careful dissection. The surface of the ciliary body and the posterior surface of the iris were examined by scanning electron microscopy. In moderate uveitis, the ciliary body was covered by a thin layer of leucocytes enmeshed in fibrin strands. Scattered deposits of fibrin and a few leucocytes were also found in the iris. In severe uveitis, the processes of the ciliary body had nearly disappeared because of oedema and exudate, which also contained erythrocytes. The numerous leucocytes had marked excrescences formed by folds of the cell membrane. Fibrin seemed to play a role in the attachment of the leucocytes on the surface of the ciliary body.