Snake-like chromatin in conjunctival cells of normal elderly persons and of patients with primary Sjögren's syndrome and other connective tissue diseases.

The aim of this study was to investigate the prevalence of snake-like chromatin in the nuclei of conjunctival cells of normal elderly persons, and to compare with findings in patients with connective tissue diseases other than primary Sjögren's syndrome and in age-matched patients with primary Sjögren's syndrome. Thirty-nine per cent of the eyes of normal controls contained snake-like chromatin. Snake-like chromatin has almost never been found in young normals, and the results of this study therefore raise the question of whether age may be a contributing factor. Snake-like chromatin was as frequent in patients with other connective tissue diseases as in patients with primary Sjögren's syndrome, and no correlation to the presence of keratoconjunctivitis sicca was found in this group. The presence of snake-like chromatin was significantly correlated to increased cell size (N/C ratio) and low goblet cell density. A marked correlation between snake-like chromatin and low values of break-up time was found in normals, whereas no correlation was found to the other standard tests for dry eye.