The palpebral conjunctival epithelium thickness in young adults measured by optical coherence tomography

To measure the palpebral conjunctival epithelium thickness in young adults with optical coherence tomography (OCT).

A Cirrus HD-OCT 4000 system was used to image the superior palpebral conjunctival with the Anterior Segment 5 Line Raster scanning protocol at the central region in 36 male and 26 female subjects aged between 20 and 30 years of age with normal, healthy eyes. The palpebral conjunctival epithelium thickness was measured according to the difference in brightness on OCT between the epithelium and its underlying substantia propria. The measurements were respectively performed in the same subjects by two operators and the Bland-Altman plot and intraclass correlation coefficient (ICC) were used to measure the agreement between two operators.

No difference in the palpebral conjunctival epithelium thickness was found between the males (34.00±5.78 μm) and females (33.67±4.51 μm) (t=0.2425, p=0.8095). The mean values of the superior palpebral conjunctival epithelium thickness from operator 1 and operator 2 were 33.81±5.04 μm and 34.74±4.28 μm, respectively. The analysis of inter-operator variability demonstrated a good agreement between two operators: ICC=0.944, F=17.787, p<0.001; on the Bland-Altman plot, the 95% limits included 100% of differences between the two operators and the maximal difference is 5 μm.

The palpebral conjunctival epithelium thickness can be measured using OCT with a good repeatability.