Thursday, November 1, 2007
The Cyclitic Membrane
In examining chronically inflamed eyeball specimens, the presence of a cyclitic membrane is not infrequently noted. A cyclitic membrane is connective tissue that extends across the eye from one aspect of the ciliary body to the other. In 1937, Dr. Harvey D. Lamb of St. Louis wrote an article entitled "The Genesis of the Cyclitic Membrane" in the Transcripts of the American Ophthalmologic Society. In it, he explains that "the essential factor in the formation of the cyclitic membrne is the conversion of the macrophage into a connective-tissue cell or fibroblast." He states that since the native fibroblasts of the ciliary body are fixed tissue cells, it "is not possible for them to proliferate through the unbroken pigmented and unpigmented ciliary epithelia". He made these claims on purely morphological grounds (hey, what do you want? it was 1937 after all). However, he does cite in vitro findings wherein cultures of macrophages underwent differentiation and yielded colonies of fibroblasts. In any case, the formation of a cyclitic membrane in chronically inflamed eyes is an interesting phenomenon and one which, when seen in enucleation specimens, I mention as part of my histologic description.