Iris vasculopathy in exfoliation syndrome. An immunocytochemical study

Samples of control iris tissue obtained from seven enucleated eyes and nine exfoliative iridectomy specimens were prepared for an immunocytochemical study of the matrix in the walls of iris vessels. The distribution of collagen types I, IV and laminin was studied in normal and exfoliative vessels. Laminin was an integral component of exfoliation material and was present mainly in the matrix of the outer surface of normal vascular cohort cells. The laminin content in the latter location was reduced in vessels in which exfoliation aggregates were not visible. Collagen type IV was absent from exfoliation material. While type I was present in the deposits, it was considered to represent a residue of native normal tissue. Exfoliation deposits appeared to stimulate the synthesis of collagen types I and IV at an early stage of the disease.