Impression Cytology on Conjunctiva and Cornea in Dry Eye Patients Establishes a Correlation between Squamous Metaplasia and Dry Eye Clinical Severity

Abstract

A morphologic and morphometric analysis of the ocular surface from patients with dry eye obtained by impression cytology led us to draft a new grading system containing one normal level and five levels of squamous metaplasia. This new grading system is based on a significant decrease in the number of goblet cells with less periodic acid-Schiff-hematoxylin-positive staining, an increase in nonsecretory cell size, more marked cell separation, a lower N:C ratio, and an increase in nuclear alterations. The clinical severity of the dry eye correlates with these alterations.