title: Signs and Symptoms of Dry Eye in Keratoconus Patients: A Pilot Study.
abstract: OBJECTIVE
  To compare signs and symptoms of dry eye in keratoconus (KC) patients versus healthy subjects.
  
  
  METHODS
  A total of 15 KC patients (KC group, n = 15 eyes) and 16 healthy subjects (control group, 16 eyes) were enrolled in this study. The Schirmer I test with no anesthetic, tear break-up time (TBUT), corneal staining characteristics, and ocular surface disease index (OSDI) scores were evaluated for both groups. Impression cytology, combined with/scanning laser confocal microscopy (LCM), was performed to evaluate goblet cell density, mucin cloud height (MCH), and goblet cell layer thickness (CLT). Finally, tear concentrations of di-adenosine tetraphosphate (Ap4A) were assessed. Results were statistically analyzed using Shapiro-Wilk and non-parametric Wilcoxon rank sum tests. Statistical significance was set at p < 0.05.
  
  
  RESULTS
  KC patients had lower tear volumes and greater corneal staining than did healthy subjects (p < 0.05). OSDI scores were 44.96 ± 8.65 and 17.78 ± 6.50 for the KC and control groups, respectively (p < 0.05). We found no statistically significant differences in TBUT between groups. Impression cytology revealed lower goblet cell densities in KC group patients versus control group subjects (84.88 ± 32.98 and 128.88 ± 50.60 cells/mm,(2) respectively, p < 0.05). There was a statistically significant reduction in MCH and CLT in KC group patients compared with control group subjects. Ap4A tear concentrations were higher in KC group patients than in control group subjects (2.56 ± 1.10 and 0.15 ± 0.12 µM, respectively, p < 0.05).
  
  
  CONCLUSIONS
  The parameters evaluated in this study indicate that KC patients suffer greater symptoms of dry eye and greater tear instability, primarily due to the decreased mucin production in their tears, than do healthy patients with no KC.
authors.affiliation: a Department of Optics II, Optometry and Vision, Faculty of Optics , Universidad Complutense de Madrid , Madrid , Spain .
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Carracedo
authors.affiliation: a Department of Optics II, Optometry and Vision, Faculty of Optics , Universidad Complutense de Madrid , Madrid , Spain .
authors.forename: Alberto
authors.initials: A
authors.lastname: Recchioni
authors.affiliation: b Department of Ophthalmology , Fundación Jimenez Diaz , Madrid , Spain , and.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Alejandre-Alba
authors.affiliation: c Department of Biochemistry and Molecular Biology IV, Faculty of Optics , Universidad Complutense de Madrid , Madrid , Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Martin-Gil
authors.affiliation: c Department of Biochemistry and Molecular Biology IV, Faculty of Optics , Universidad Complutense de Madrid , Madrid , Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Crooke
authors.affiliation: b Department of Ophthalmology , Fundación Jimenez Diaz , Madrid , Spain , and.
authors.forename: Ignacio Jimenez-Alfaro
authors.initials: IJ
authors.lastname: Morote
authors.affiliation: c Department of Biochemistry and Molecular Biology IV, Faculty of Optics , Universidad Complutense de Madrid , Madrid , Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Pintor
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D002452:Cell Count; D015226:Dinucleoside Phosphates / Q000378:metabolism*; D015352:Dry Eye Syndromes / Q000175:diagnosis* / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D005260:Female; D020397:Goblet Cells / Q000378:metabolism / Q000473:pathology; D064368:Healthy Volunteers; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D009077:Mucins / Q000378:metabolism*; D010865:Pilot Projects; D011795:Surveys and Questionnaires; D013666:Tears / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015226:Dinucleoside Phosphates; D005136:Eye Proteins; D009077:Mucins; C042434:tear proteins; C020733:diadenosine tetraphosphate
keywords: 3D impression cytology; dinucleotide; dry eye; keratoconus