Experimental posterior penetrating eye injury in the rabbit. II. Histology of wound, vitreous, and retina.

The histological findings of the wound, the vitreous, and the retina in the rabbit eye with experimental posterior penetrating injury are described. Wound healing had just begun at 3 days after injury and was well established by 9 to 12 days. It involved proliferation of cells from the episclera and from the choroid. The progression to a fibrous ingrowth from the wound occurred only in eyes with blood in the vitreous. The intravitreal fibroblastic proliferation had begen at 6 days after injury and seemed to be derived from the choroid, the nonpigmented ciliary epithelium and, posteriorly, from the optic nervehead. During the development of retinal detachment the configuration of the peripheral and posterior retina, together with the orientation of vitreous strands, suggested the presence of vitreous traction. We postulate that the presence of contractile fibroblasts (myofibroblasts) in the vitreous may provide the mechanism for vitreous traction. The retinal detachments were also characterised by epiretinal and subretinal membranes, but these were not prominent. The end-stage appearance of a soft, shrunken eye with cyclitic membrane formation and retinal detachment resembles the outcome in many human eyes after severe penetrating injuries.