title: Progress in tear microdesiccate analysis by combining various transmitted-light microscope techniques.
abstract: BACKGROUND
  Tear desiccation on a glass surface followed by transmitted-light microscopy has served as diagnostic test for dry eye. Four distinctive morphological domains (zones I, II, III and transition band) have been recently recognized in tear microdesiccates. Physicochemical dissimilarities among those domains hamper comprehensive microscopic examination of tear microdesiccates. Optimal observation conditions of entire tear microdesiccates are now investigated. One-μl aliquots of tear collected from individual healthy eyes were dried at ambient conditions on microscope slides. Tear microdesiccates were examined by combining low-magnification objective lenses with transmitted-light microscopy (brightfield, phase contrasts Ph1,2,3 and darkfield).
  
  
  RESULTS
  Fern-like structures (zones II and III) were visible with all illumination methods excepting brightfield. Zone I was the microdesiccate domain displaying the most noticeable illumination-dependent variations, namely transparent band delimited by an outer rim (Ph1, Ph2), homogeneous compactly built structure (brightfield) or invisible domain (darkfield, Ph3). Intermediate positions of the condenser (BF/Ph1, Ph1/Ph2) showed a structured roughly cylindrical zone I. The transition band also varied from invisibility (brightfield) to a well-defined domain comprising interwoven filamentous elements (phase contrasts, darkfield).
  
  
  CONCLUSIONS
  Imaging of entire tear microdesiccates by transmitted-light microscopy depends upon illumination. A more comprehensive description of tear microdesiccates can be achieved by combining illumination methods.
authors.affiliation: Cellular and Molecular Biology Program, Faculty of Medicine-ICBM, University of Chile, Independencia 1027, Independencia, Postal code 8380453, Santiago, Chile.
authors.forename: Felipe
authors.initials: F
authors.lastname: Traipe-Salas
authors.affiliation: Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile.
authors.forename: Leonidas
authors.initials: L
authors.lastname: Traipe-Castro
authors.affiliation: Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile.
authors.forename: Daniela
authors.initials: D
authors.lastname: Salinas-Toro
authors.affiliation: Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile.
authors.forename: Daniela
authors.initials: D
authors.lastname: López
authors.affiliation: Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile.
authors.forename: Felipe
authors.initials: F
authors.lastname: Valenzuela
authors.affiliation: Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile.
authors.forename: Christian
authors.initials: C
authors.lastname: Cartes
authors.affiliation: Cellular and Molecular Biology Program, Faculty of Medicine-ICBM, University of Chile, Independencia 1027, Independencia, Postal code 8380453, Santiago, Chile.
authors.forename: Héctor
authors.initials: H
authors.lastname: Toledo-Araya
authors.affiliation: Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile.
authors.forename: Claudio
authors.initials: C
authors.lastname: Pérez
authors.affiliation: Cellular and Molecular Biology Program, Faculty of Medicine-ICBM, University of Chile, Independencia 1027, Independencia, Postal code 8380453, Santiago, Chile. rlopez@med.uchile.cl.
authors.forename: Remigio
authors.initials: R
authors.lastname: López Solís
mesh_terms: D000293:Adolescent; D000328:Adult; D003890:Desiccation / Q000379:methods*; D015352:Dry Eye Syndromes / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008027:Light; D008029:Lighting; D008297:Male; D008858:Microscopy, Phase-Contrast / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D013499:Surface Properties; D013666:Tears / Q000000981:diagnostic imaging* / Q000378:metabolism; D055815:Young Adult
keywords: Dry eye; Tear; Tear ferning test; Tear microdesiccate; Transmitted-light microscopy