AIM: To investigate the changes of corneal cytology of patients with different degrees of xerophthalmia of the types of deficient aqueous production and over evaporation with confocal microscopy.

METHODS: Retrospective case series was adopted with three-dimensional corneal topography and anterior segment analysis system(Sirius system). A total of 33 typical dry eye patients(total 65 eyes)with deficient aqueous production and 28 typical dry eye patients(total 55 eyes)with over evaporation were selected from optical center of the First Affiliated Hospital of Harbin Medical University from December 2016 to June 2017, which were grading according to dry eye degrees. The corneal epithelial cell(surface epithelial cell, pterygoid epithelial cell, basal epithelial cell), Langerhans cell(dendritic cell), stroma(deep stromal layer and superficial stromal layer), the density and form of endothelial cells were observed and analyzed with the confocal microscope.

RESULTS: Confocal microscope showed that the number of corneal epithelial cells decreased with the increasing of dry eye severity in patients with tear deficiency and evaporative. The results were statistically significant(P<0.01). The sizes of each layer of corneal epithelium cells were uneven, and the arrangement was irregular. The diameter of corneal sub-epithelial nerve fiber of deficient aqueous production dry eye became thinner with irregular arrangement. With the increase in severity of dry eye, the degree of curvature and branches gradually increased. The activation degree of Langerhans cells of evaporative dry eye was directly proportional to the severity of dry eye(P<0.01). There was no significant changes in the number of superficial stromal cells in the two types of dry eye(P>0.05). The number of deep stromal cells in the two types of dry eye had no relations with the severity of dry eye(P>0.05). There was no significant changes in the number of corneal endothelial cells in the two types of dry eye(P>0.05).

CONCLUSION: The Sirius system can be used for non-contact and non-invasive examination and classification. And there is changes of the density and morphology in each layers of cornea cells of two types of dry eye with the confocal microscope.