Purpose
To investigate the features of corneal epithelial thickness topography with Fourier-domain optical coherence tomography (OCT) in dry eye patients.
Methods
In this cross-sectional study, 100 symptomatic dry eye patients and 35 normal subjects were enrolled. All participants went through ocular surface disease index (OSDI) questionnaire, corneal fluorescein staining, tear break-up time (TBUT), Schirmer I test without anesthetic (S1t), and meibomian morphology. Corneal epithelial thickness was mapped by Fourier-domain OCT with Pachymetry+Cpwr scan pattern. Several epithelium statistics for each eye, including central, superior, inferior, minmum, maximum, minimum-maximum (Min-Max), and map standard deviation (MSD) were averaged. Correlations of epithelial thickness with the signs and symptoms of dry eye were calculated.
Results
The mean central, superior, and inferior corneal epithelial thickness was 53.57±3.31μm, 52.00±3.39μm and 53.03±3.67μm in normal eyes; and 52.71±2.83μm, 50.58±3.44μm and 52.53±3.36μm in dry eyes. The superior corneal epithelium was thinner in dry eye patients compared with normal subjects (P=0.037). In dry eye group, patients with higher severity grades had thinner superior (P=0.017) and minimum (P<0.001) epithelial thickness, more negative Min-Max (P=0.032), and greater MSD (P=0.003). The average central epithelial thickness had no correlation with TBUT, S1t or the severity of meibomian glands; while average superior epithelial thickness positively correlated with S1t (r=0.238, P=0.017).
Conclusions
Fourier-domain OCT demonstrated that the thickness map of the dry eye corneal epithelium was thinner than normal eyes in the superior region. In severer dry eye disease patients, the superior and minimum epithelium was much thinner, with a greater range of map standard deviation.
Keywords: 482 cornea: epithelium •
486 cornea: tears/tear film/dry eye