Schirmer tear test-1 with open or closed eyelids: An evaluation in brachycephalic and nonbrachycephalic dogs

Oren Pe'er*, Ron Ofri, Lionel Sebbag

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Purpose: Assess aqueous tear production when measured with the dogs' eyelids open or closed. Methods: Thirty healthy dogs (15 Shih Tzus, 15 Labrador retrievers) were recruited. With the order of testing randomized for each dog, two sessions (separated by 30 min) of STT-1 testing were performed with the dogs' eyelids closed or open. Schirmer strip wetness (every 10 s for 60 s) and number of time(s) the strip dislodged during testing were recorded in each eye. Preferred STT-1 method was surveyed via a global Listserv of the veterinary ophthalmology community. Results: STT-1 values were significantly higher in closed versus open eyes in Shih Tzus (18.6 ± 2.7 mm/min vs. 16.3 ± 2.5 mm/min; p =.002) and Labrador retrievers (21.6 ± 2.9 mm/min vs. 17.8 ± 3.2 mm/min, p <.001), findings that were also significant at times <60 s for either breed (p ≤.004). Schirmer strips dislodged from six dogs with open eyelids and no dogs with closed eyelids. Maximal STT-1 difference with closed versus open eyelids was 13 mm/min in Labrador retrievers and 7 mm/min in Shih Tzus. Survey results from 275 veterinarians showed STT-1 performed with “closed eyelids” (38.5%), “open eyelids” (26.9%), or “never paid attention, sometimes closed, sometimes open” (34.6%). Conclusions: Eyelids status (closed or open) during STT-1 testing had a significant impact on aqueous tear secretion in brachycephalic and nonbrachycephalic dogs, highlighting the importance of consistency when repeating STT-1 in a canine patient. STT-1 differences are likely due to sustained reflex tearing throughout the test duration when the dogs' eyelids are closed.

Original languageAmerican English
JournalVeterinary Ophthalmology
StateAccepted/In press - 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors. Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.


  • aqueous tear secretion
  • canine
  • dry eye
  • keratoconjunctivitis sicca
  • palpebral fissure
  • reflex tearing


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