title: Assessment of corneal epithelial thickness in dry eye patients.
abstract: OBJECTIVE
  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 answered the ocular surface disease index questionnaire and were subjected to OCT, corneal fluorescein staining, tear breakup time, Schirmer 1 test without anesthetic (S1t), and meibomian morphology. Several epithelium statistics for each eye, including central, superior, inferior, minimum, maximum, minimum - maximum, and map standard deviation, were averaged. Correlations of epithelial thickness with the symptoms of dry eye were calculated.
  
  
  RESULTS
  The mean (±SD) central, superior, and inferior corneal epithelial thickness was 53.57 (±3.31) μm, 52.00 (±3.39) μm, and 53.03 (±3.67) μm in normal eyes and 52.71 (±2.83) μm, 50.58 (±3.44) μm, and 52.53 (±3.36) μm in dry eyes, respectively. The superior corneal epithelium was thinner in dry eye patients compared with normal subjects (p = 0.037), whereas central and inferior epithelium were not statistically different. In the dry eye group, patients with higher severity grades had thinner superior (p = 0.017) and minimum (p < 0.001) epithelial thickness, more wide range (p = 0.032), and greater deviation (p = 0.003). The average central epithelial thickness had no correlation with tear breakup time, S1t, or the severity of meibomian glands, whereas 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 more severe dry eye disease patients, the superior and minimum epithelium was much thinner, with a greater range of map standard deviation.
authors.affiliation: *MD †MD, PhD Department of Ophthalmology, Eye, Ear, Nose, and Throat Hospital, School of Shanghai Medicine, Fudan University, Shanghai, China (XC, JH, FW, YY, DW, YZ, JX); School of Life Sciences, Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen, China (JH); State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai, China (JH); Health Communication Institute, Fudan University, Shanghai, China (JH); Department of Ophthalmology, the Jules Stein Eye Institute, University of California, Los Angeles, California (SXD); and Department of Ophthalmology, Jinshan Hospital, School of Shanghai Medicine, Fudan University, Shanghai, China (XZ).
authors.forename: Xinhan
authors.initials: X
authors.lastname: Cui
authors.forename: Jiaxu
authors.initials: J
authors.lastname: Hong
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: Sophie X
authors.initials: SX
authors.lastname: Deng
authors.forename: Yujing
authors.initials: Y
authors.lastname: Yang
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhu
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Yujin
authors.initials: Y
authors.lastname: Zhao
authors.forename: Jianjiang
authors.initials: J
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D063171:Corneal Pachymetry; D003430:Cross-Sectional Studies; D015352:Dry Eye Syndromes / Q000473:pathology*; D019573:Epithelium, Corneal / Q000473:pathology*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011795:Surveys and Questionnaires; D013666:Tears / Q000737:chemistry; D041623:Tomography, Optical Coherence / Q000379:methods; D055815:Young Adult