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Evaluation of tear production using the Schirmer tear test I in healthy cats; effect of age, life stage, sex, breed and neuter status
  1. Seyed Mehdi Rajaei1,2,
  2. Houman Faghihi3,
  3. David Leonard Williams4 and
  4. Ghazal Aftab3
  1. 1 Ophthalmology Section, Negah Veterinary Centre, Tehran, Iran
  2. 2 Department of Clinical Sciences, College of Veterinary Medicine, Islamic Azad University, Karaj Branch, Karaj, Alborz, Iran
  3. 3 Department of Clinical Sciences, Faculty of Specialized Veterinary Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
  4. 4 Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
  1. E-mail for correspondenceOphthalmology Section, Negah Veterinary Centre, Tehran, Iran ; Mehdi_13r{at}


Background The purpose of this study was to evaluate the values of Schirmer tear test (STT) and determine effects of age, life stage, sex, breed and neuter status on tear production in healthy cats.

Methods Three hundred and forty-three domestic shorthair (DSH) and Persian cats, 50 days through 18 years old, were examined in this study. STT I was used to measure tear production in both eyes of each cat.

Results A mean STT 14.9±4.8 mm/min was calculated for the eyes of all cats. There was a significant difference between STT values in kittens (≤6 months old) and cats of other age groups (P<0.001). A substantial number of cats with clinically normal eyes had STT values less than 10 mm/min. No significant difference was found between males (14.7±5.0 mm/min) and females (15.1±4.5 mm/min) in STT values (P=0.46). Significant differences were found between entire (14.4±4.2 mm/min) and neutered (16.2±4.1 mm/min) cats (P=0.001), and between STT values of DSH (14.6±5.0 mm/min) and Persian (16.5±3.1 mm/min) cats in the study population (P=0.001).

Conclusions This study documents the average STT values for a sizeable feline population demonstrating that, in contradistinction to the situation in dogs, a number of cats with clinically normal eyes have STT values below 10 mm/min.

  • ophthalmology
  • cats
  • physiology
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  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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