Dry eye disease, or keratoconjunctivitis sicca, is among the most frequentl
y established diagnoses in ophthalmology; in Germany, one in four patients
consulting an ophthalmologist complains of the symptoms of dry eye. Althoug
h epidemiological studies investigating the prevalence of dry eye disease a
re rare, published studies indicate that up to 20% of adults aged 45 years
or more experience dry eye symptoms. Recent studies have shown that immunol
ogic changes play a role in the pathogenesis of dry eye, not only in Sjogre
n's syndrome, but also in postinfectious and age-related conditions. Despit
e increasing understanding of the pathogenic factors involved in dry eye di
sease, there has been a lack of consensus on diagnostic criteria, classific
ation of disease states, and the aims and interpretation of specific diagno
stic tests. There is a need, therefore, for standardization of disease term
inology and diagnostic tests in order to improve the use fulness of epidemi
ological and clinical investigation of this important ocular disorder. (Sur
v Ophthalmol 45(Suppl 2):S199-202, 2001. (C) 2001 by Elsevier Science Inc.
All rights reserved).