Using in vivo confocal microscopy (IVCM), researchers have identified how corneal immune dendritiform cells (DC) change in patients with dry eye disease (DED), according to newly published research in The Ocular Surface. The Harvard Medical School–based research team concluded that DC density and morphology correlate with disease severity. DC density is high in mild DED, the investigators explain, but morphological changes are only seen in severe cases. IVCM can help detect early immune changes in DED, the team added.

The investigators looked at 300 eyes of 150 DED patients and 49 eyes of 49 age-matched controls. They used parameters set forth by the TFOS Dry Eye Workshop  to classify the patients’ dry eye status. They used IVCM imaging of the central cornea’s subbasal layer to establish DC density and morphology, including number of dendrites per DC, as well as their size and field.

The data shows DC density was significantly higher in dry eye patients, who had 93.4 cells/mm (±6.3 cells/mm) compared with the controls, which had 25.9 cells/mm (±3.9 cells/mm). These changes were seen as early as Level 1 DED severity, the study shows

The number of dendrites, DC size and field were all significantly larger in DED patients too. These morphological changes were detected at Levels 2 to 4, respectively. However, DC size showed an even more significant increase at DED Levels 3 and 4. Both conjunctival and corneal staining were independently associated with DC density, while corneal staining was independently associated with DC morphology, the study shows.

Aggarwal S, Kheirkhah A, Cavalcanti B, et al. Correlation of corneal immune cell changes with clinical severity in dry eye disease: An in vivo confocal microscopy study. The Ocular Surface. June 3, 2020. [Epub ahead of print].