Any attempt at the categorisation of patients suffering from dry eyes presents the investigator with a complex problem, constantly evolving in the light of new discoveries.

Primary and secondary Sjögren’s syndrome and the rarer Sjögren’s syndrome in childhood, certainly show features of generalised disease distinctive from each other. Primary Sjögren’s syndrome describes a range of patients who may suffer predominantly from surface exocrine disease—for example, involving the eyes, mouth, or genital tract, or internal exocrine disease affecting the lung parenchyma hepatobiliary system, or pancreas.1-6 Secondary Sjögren’s syndrome victims, in general, present with rheumatoid arthritis or another connective tissue disorder such as systemic lupus erythematosus or dermatomyositis.2 These two conditions although sharing many clinical and laboratory features are also distinguishable from each other in that they display different ranges of autoantibodies,3-5 genetic predisposition,5-9 possible reaction to viruses such the Epstein–Barr virus,810-12 and retroviruses.1314

Keratoconjunctivitis sicca …