Abstract
Purpose :
Corneal epithelial dendritic cell body size, length and shape of dendrites are associated with corneal inflammation. However, corneal epithelial dendritic cell (CEDC) morphology is commonly characterised using dendrite length (DL) only. This study aimed to examine the inter- and intra-rater repeatability of a novel CEDC morphology grading scale that is characterised by both cell body (CB) and dendrite shape (DS). Associations between different characteristics (CB, DS and DL) were also assessed.
Methods :
CEDC morphology was graded on 80 corneal sub-basal nerve plexus images captured by in vivo confocal microscopy with Rostock Corneal Module from database of School of Optometry and Vision Science, UNSW. Grading scale was applied by 2 experienced observers for inter-rater repeatability and by a single observer at 2 time points, 3 days apart for intra-rater repeatability. CB was graded as 1: small (10-25 µm), 2: medium (26-40 µm) and 3: large (>41µm). DS was graded as 1: no dendrites, 2: thin dendrites and 3: thick dendrites. CEDC morphology was also graded based on DL as 1: no dendrite, 2: Linear structures with small dendrites and 3: X and Y shaped with longest visible dendrites. The most frequent and the highest-grade morphology were recorded for each and the inter- and intra-rater repeatability was examined. The level of agreement between observers and within observer was evaluated using weighted kappa (κ >0.80 considered excellent repeatability). Cramer’s V test (> 0.30 considered strong) examined the association between the most frequent CEDC characteristics.
Results :
There were strong inter- and intra-rater agreements in most frequent CB (κ=0.91, κ=0.93 respectively), biggest CB (κ=0.88, κ=0.89 respectively), most frequent DS (κ=0.90, κ=0.92, respectively) and thickest dendrites (κ=0.93, κ=0.88 respectively). Strong inter- and intra- rater agreements were found for most frequent DL (κ=0.93, κ=0.96 respectively) and longest dendrites (κ=0.98, κ=0.93 respectively). Longer DL was associated with bigger CB (Cramer’s V=0.49, p<0.001) and with thinner dendrites (Cramer’s V=0.71, p<0.001). Thinner dendrites were associated with medium and larger CB (Cramer’s V=0.39, p<0.001).
Conclusions :
A novel grading scale of CEDC characteristics was highly repeatable. A consideration of all CEDC characteristics could provide a comprehensive description of the CEDC morphology.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.