Impression conjunctival cytology in sicca syndrome - correlations between clinical and histological findings related to dry eye severity

Keratoconjunctivitis sicca represents a progressive deterioration of ocular surface produced by a deficient secretion of lachrymal film (quantitative disorder) or excessive tear evaporation (qualitative disorder). The cytological analysis of conjunctival impression in 42 patients with dry eye syndrome established a strong correlation between the clinical grade of severity of disease and the grade of squamous metaplasia, including goblet cell loss. The cellular anomalies were represented by modifications of keratinization, epithelial cells' anisocytosis, anisochromia, the nuclear condensation and the cytoplasmic vacuolization. Pyknotic nuclei and anucleated cells were only seen in the most severe dry eye. The modifications in epithelial cells and conjunctival goblet cells reveal cellular sufferance, with an evident parallelism between these anomalies and clinico-functional signs in dry eye. Conjunctival impression provides an easy and quick identification of the lachrymal film alterations with high specificity and sensitivity, giving valuable information about the qualitative disorder.