Diurnal Variation of Corneal Dendritic Cell Density

Abstract

Purpose: To measure variation in corneal dendritic cell density, and percentage of mature to total dendritic cells, in healthy individuals during the sleep/wake cycle.

Methods: Using in vivo confocal microscopy, images of the subbasal nerve plexus were captured from 19 healthy, noncontact lens wearing participants. The central cornea and inferior whorl were imaged three times (midday, before sleep, upon awakening). Dendritic cell counts from the images were categorized according to perceived maturity (immature vs mature). Dendritic cell density and percentage of mature to total cells were compared between time points.

Result: The median and interquartile range (IQR) of total dendritic cell density in the central cornea was 32.0 (7.0–131.3) cells/mm² at midday, 37.1 (8.2–103.9) cells/mm² before sleep, and 19.5 (7.0–83.2) cells/mm² on awakening. Corresponding values for immature cells were 28.1 (5.8–112.5) cells/mm², 22.3 (7.4–84.0) cells/mm² and 18.0 (2.9–64.8) cells/mm², and for mature cells, 3.1 (0.0–6.6) cells/mm², 2.0 (0.8–16.8) cells/mm², and 1.6 (0.2–8.2) cells/mm². At the inferior whorl, total dendritic cell density was 38.5 (18.4–84.5) cells/mm², 34.4 (9.4–82.3) cell/mm², and 32.3 (15.2–96.1) cells/mm². Immature cell density was 32.8 (18.4–80.9) cells/mm², 34.4 (8.6–81.0) cells/mm², and 32.3 (12.6–78.5) cells/mm². Mature cell density was 1.6 (0.0–6.3) cells/mm², 1.6 (0.0–3.1) cells/mm², and 1.8 (0.0–6.3) cells/mm². There was no significant difference between time points for total cell density (p > 0.05), but the percentage of mature cells upon awakening was significantly greater, compared to midday, at the central cornea (p = 0.02).

Conclusion: In healthy individuals, overall corneal dendritic cell density is reasonably constant during the sleep/wake cycle, but the relative number of mature cells tends to increase overnight.

Keywords:

• Corneal dendritic cell density
• ocular surface
• confocal microscopy
• central cornea
• inferior whorl

Submission declaration

This work is original, has not been published and is not being considered for publication elsewhere. There are no conflicts of interest for any of the authors that could have influenced the results of this work. All authors have contributed significantly to the project and subsequent drafting, revising and approval of the final version submitted.

Grant information

Sultan Alotaibi is sponsored by King Saud University, Riyadh, Kingdom of Saudi Arabia. The project was funded by CooperVision, Inc. (Pleasanton, USA).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data available on request from the corresponding author.