Characterization of human orbital fat and connective tissue

This study was designed to evaluate the characteristics of human orbital fa t and connective tissue. Two exenteration specimens were studied by light m icroscopy with special stains. Four distinct regions were identified on the basis of their connective tissue septa, which contained blood vessels and were composed of elastin and collagen types I, III, and IV. Transmission el ectron microscopy was performed on the opposite orbits. The fibroblasts and adipocytes appeared metabolically inactive and showed no regional differen ces. The fat was phase extracted from the connective tissue and subjected t o biochemical analysis. No regional differences were found in the content o f fatty acids and protein. The fatty acids included palmitic acid (22-24.6% ), oleic acid (45-51.5%), and linoleic acid (15-18.6%). Despite demarcation of the orbital fat into distinct regions by the connective tissue septa, u ltrastructural and biochemical analysis revealed no regional variations in the fat. The diagnostic and therapeutic implications of these findings are discussed.