First, to assess the use of impression cytology, clinical and laboratory tests in the daily clinic for the early diagnosis of Primary Sjögren Syndrome (SS1), and second, to establish morphological differences between SS1, keratoconjunctivitis sicca (KCS) and healthy controls using impression cytology.
The study comprised 35 patients suffering from primary Sjögren syndrome, same number of patients with keratoconjunctivitis sicca and normal healthy subjects. All groups underwent clinical tests (Schirmer's test, break-up time, and bengal rose staining), laboratory tests (tear protein pattern, tear osmolarity and serum immunoglobulin readings), and impression cytology on different areas of the conjunctiva and cornea.
All patients presented one or more subjective symptoms of ocular irritation although seeming normal at naked eye. Two patients with Sjögren's syndrome showed total corneal keratinization. Clinical and laboratory tests did not show significant differences between Sjögren's syndrome patients group and keratoconjunctivitis group. Serum tests of antibodies and immunoglobulins did present diagnostic values. Impression cytology showed significant differences between Sjögren syndrome patients compared to the rest of groups with regard to epithelial and goblet cells.
Impression cytology consists in a hystopathological test and it is considered the only ophtalmological test that offers a differential diagnosis in Sjögren's syndrome and should be included in a classification criteria. Inpression cytology presents significant differences between Sjögren syndrome and keratoconjunctivitis sicca.