title: Comparing tear film stability prolongation evaluated by Javal-Schiotz keratometer and slitlamp.
abstract: OBJECTIVE
  To innovatively compare the tear film stability assessed noninvasively by Javal-Schiotz keratometer (tear deformation time [TDT]) and invasively by slitlamp (invasive tear breakup time [I-TBUT]).
  
  
  METHODS
  Tear deformation time and I-TBUT were assessed in only 1 eye of 100 healthy young participants aged from 18 to 25 years (mean±standard deviation=20.49±1.80). Healthy ocular surface was considered as inclusive criteria. Nonparametric statistical analysis was performed to compare the TDT with I-TBUT and reveal correlation between them.
  
  
  RESULTS
  The TDT values (mean: 22.84±20.14 sec) were significantly higher than the I-TBUT (mean: 15.73±8.89 sec) data (P=0.027). Neither TDT nor I-TBUT was affected by gender of the subjects. A significant direct correlation was detected between the TDT and I-TBUT data (Spearman ρ=0.458, P<0.0001). Neither I-TBUT nor TDT showed a significant relationship with age and sex factors.
  
  
  CONCLUSIONS
  Our findings indicated that tear stability prolongation results obtained by TDT technique were significantly higher than the I-TBUT method outcomes. Noninvasive nature, easiness, basal tear film evaluation, availability, inexpensiveness, Fluorescein nonuse, and accessibility in the clinic (no need for para-clinical equipment) are benefits of the TDT technique. Future studies must be aimed at evaluating validity and reliability of the TDT technique on normal and dry eye populations.
authors.affiliation: Department of Optometry (A.A., E.J., A.M.), Iran University of Medical Sciences, Tehran, Iran; and Department of Epidemiology (M.K.), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Asharlous
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Jafarzadehpur
authors.forename: Ali
authors.initials: A
authors.lastname: Mirzajani
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khabazkhoob
mesh_terms: D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000502:physiology; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D066167:Slit Lamp; D013666:Tears / Q000502:physiology*; D055815:Young Adult