Sutures and iris wound-healing in the baboon.

: This paper reports an experimental study of iris wound-healing and the response of iris tissue in baboons to different suture materials following a planned surgical incision. The wound was sutured with 8-0 virgin silk, 22 mum Ethilon or 7-0 chromacised catgut, or left unsutured. The iris produces a minimal inflammatory response to aseptic trauma characterised by round cell infiltration, clump cell proliferation, pigment cell proliferation from the posterior epithelial surface and proliferation of non-pigmented ciliary epithelium (knots). This response is associated with microscopic hemorrhages in the iris. There does not appear to be any fibrous union of wound edges, instead the wound surfaces become lined with a layer of pigmented cells, probably from the posterior epithelium. Sutures play the dual role of accurately apposing the wound edges and, because there is no fibrous union of iris tissue, of keeping them in apposition. Therefore, they must remain in situ permanently. Catgut is poorly tolerated by the iris and is eventually absorbed. For these two reasons it is unsuitable. Ethilon is the least reactive and virgin silk only slightly more reactive. Both of these are suitable for iris suture. The suture material at present available is not entirely satisfactory. Finer suture material is required to reduce even more the iris response to sutures. Needles, even those supplied with Ethilon or virgin silk, are too large and clumsy. The answer to this problem probably lies in strengthening and sharpening the suture material ends so that they can act as needles.