Diurnal changes in corneal dendritic cell density and morphology in symptomatic and asymptomatic contact lens wearers

Abstract

Purpose : To explore corneal dendritic cell (DC) density and morphology in soft contact lens (CL) wearers using in vivo confocal microscopy (IVCM) after different wear times, imaging with and without CLs in situ.

Methods : This was a prospective study involving hydrogel and silicone hydrogel CL wearers (17F, 3M; 29.5±10.5 years): 10 symptomatic (S-CL) and 10 asymptomatic (A-CL), by Young’s criterion and comfortable wear time. Eligible participants attended a baseline day (no CL wear, IVCM conducted in the morning (AM) and 8 hours later (PM), three separate CL wearing days (IVCM after 1, 4 or 8 hours [randomized] with CLs removed immediately before imaging and topical anesthesia), and a day where CLs were worn all day (IVCM after 1, 4 and 8 hours of CL wear, with CLs in situ during imaging and no anesthesia). At least five non-overlapping sequence scans were taken at the central and inferior cornea with the Heidelberg Retina Tomograph III with Rostock Cornea Module. Up to five images per location were analyzed with automated DC counting software. A linear mixed model was applied for all statistical analyses.

Results : At the central cornea, DC density was greater in the AM/1 hour compared to PM/8 hours (p<0.001), and for the A-CL group compared to the S-CL group (p=0.041). There was no effect of imaging with CLs in situ on DC density; DC density with and without CLs in situ strongly correlated across all time points at both corneal locations (r=0.694 to 0.843, all p≤0.01). For cell morphology, immature dendritic cells were the dominant cell type in both groups at both locations (S-CL ≥77%, A-CL ≥78%). Mature cells made up 8-15% of all DCs. The A-CL group had 5% more mature cells than the S-CL group at the inferior cornea only (p=0.034). At both locations, 5% more mature cells were observed on lens wearing days (central p=0.043, inferior p=0.027). Time of imaging was not a significant effect on the proportion of immature or mature cells at either location.

Conclusions : This study shows subtle differences in DC density and morphology between symptomatic and asymptomatic CL wearers and over the course of the day in different corneal regions. The clinical significance of these results requires further investigation. This study supports the imaging of DCs with CLs in situ, which could simplify monitoring these cells during CL wear.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.