In vivo confocal microscopic evaluation of corneal langerhans cells in dry eye patients

Purpose: To assess inflammatory involvement of cornea in dry eye by means of confocal microscopy, evaluating the presence and distribution of Langherans cells (LCs).

Methods: 98 eyes of 49 subjects were enrolled: 18 subjects affected by Sjögren Syndrome Dry Eye (SSDE), 17 with Non-Sjögren Syndrome Dry Eye (NSSDE), 14 healthy volunteeers. Dry eye symptoms, tear film, ocular surface damage and corneal confocal microscopy were analized.

Results: A significant increase of LCs density was observed at sub-basal nerve plexus (SSDE = 79 cells/mm(2) andNDE = 22 cells/mm(2); p = 0,0031) and sub-epithelial nerve plexus (SSDE = 38 cells/mm(2) and NDE = 3 cells/mm(2); p = 0,0169) in central cornea of SSDE group. An increased number of LCs from the center to the periphery of the cornea was observed, significant only in healthy volunteers group. In dry eye patients there was an increase in LCs density in both peripheral and central cornea with a significant difference between NDE (14,66 cells/mm(2)) and SSDE (56,66 cells/mm(2)) only in central cornea (p = 0,0028). In SSDE group, mean density of LCs in central cornea results also superior to NSSDE group (29,33 cells/mm(2)). There was no correlation between LCs density and dry eye symptoms, tear film deficiency and ocular surface damage.

Conclusion: This study demonstrates the activation of an inflammatory and immunological reaction in cornea of NSSDE and SSDE patients. Confocal microscopy can be an important diagnostic tool in evaluation and follow-up of dry eye disease.