Reliability of confocal corneal microscopy for measurement of dendritic cell density in suspected small fiber neuropathy.

INTRODUCTION/AIMS: Dendritic cells (DCs) and their contacts with corneal nerves are described in animal models of nerve damage. Dendritic cell density (DCD) is a potential marker of immune activity in suspected small-fiber neuropathy (SFN). Here, we aim to evaluate the intra- and inter-rater reliability of DCD measurements in suspected SFN.

METHODS

This retrospective study collected DCD from confocal microscopy images from the corneal sub-basal epithelium of the eye from 48 patients (mean age 49.6 ± 12.1 y, 61% female). Two examiners, each blinded to the other's examinations and measurements, assessed DCD to evaluate inter-rater reliability. For intra-rater reliability, the first examiner performed a second measurement after 14 days. DCs were classified into two cell morphological subtypes: mature and immature.

RESULTS

Test-retest reliability for total DCD showed excellent agreement, with an intraclass correlation coefficient of 0.96 and inter-rater reliability intraclass correlation coefficient of 0.77. The immature cell subtype showed excellent intra-rater reliability but lower inter-rater reliability.

DISCUSSION

We found that DCD measurements in the corneal sub-basal epithelium are sufficiently reliable for consideration in clinical studies of patients with suspected SFN.