title: Characterization by Belmonte's gas esthesiometer of mechanical, chemical, and thermal corneal sensitivity thresholds in a normal population.
abstract: OBJECTIVE
  We used a prototype gas esthesiometer to measure corneal threshold sensitivity values for mechanical, chemical, and thermal stimuli. We also evaluated the reproducibility of the esthesiometer measurements, the influence of previous corneal symptoms, and the safety of this technique.
  
  
  METHODS
  Forty healthy subjects participated in the study. Mechanical, chemical, and thermal (hot and cold) thresholds were determined at the center of the cornea using a prototype Belmonte's gas esthesiometer. To determine reproducibility of the results, the sensitivity thresholds were measured for each eye on 2 days. Corneal fluorescein staining and bulbar hyperemia after completion of the tests were analyzed.
  
  
  RESULTS
  There were no differences for any sensitivity threshold between eyes or between the first and second esthesiometries. The reproducibilities of mechanical and hot thresholds were higher than for chemical and cold thresholds. Men had significantly higher chemical intensity thresholds than did women (men: 23.50 ± 5.10; women: 10.20 ± 2.16, P = 0.021). There were no alterations of the ocular surface after completion of the measurements.
  
  
  CONCLUSIONS
  Mechanical, chemical, and thermal corneal sensitivity thresholds in the central cornea have been established in healthy men and women of different age groups. The use of the Belmonte gas esthesiometer is safe and reproducible, with the highest reproducibility in determining mechanical and hot thresholds.
authors.affiliation: Instituto Universitario de Oftamobiología Aplicada, University of Valladolid, Campus Universitario Miguel Delibes, Paseo de Belén 17, Valladolid, Spain. mtesony@ioba.med.uva.es
authors.forename: Marisa
authors.initials: M
authors.lastname: Tesón
authors.forename: Margarita
authors.initials: M
authors.lastname: Calonge
authors.forename: Itziar
authors.initials: I
authors.lastname: Fernández
authors.forename: Michael E
authors.initials: ME
authors.lastname: Stern
authors.forename: María J
authors.initials: MJ
authors.lastname: González-García
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D005740:Gases; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D010812:Physical Stimulation / Q000379:methods; D012016:Reference Values; D015203:Reproducibility of Results; D012677:Sensation / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology*; D013268:Stimulation, Chemical; D055815:Young Adult
chemical_list: D005740:Gases