Reference values for intraocular pressure and Schirmer tear test in clinically normal Sanjabi sheep

Abstract

The current study was undertaken to establish reference values for Schirmer tear test (STT) and intraocular pressure (IOP) in the Sanjabi sheep. Twenty apparently healthy Sanjabi sheep with no evidence of ocular disease were used in this study. Tear production was measured by STT by inserting standard sterile Schirmer tear test strip (Ophtechnics Inc., Carson City, NV, USA, Lot number: STR061203) in the ventral conjunctival fornix for 1 min. IOP was measured in both eyes with a Tono-Pen Vet™ (Reichert, Inc. USA). Mean (SD) STT values for all eyes ( n = 40) were 18.52 ± 2.55 mm/min with a range of 13.5–22 mm/min. Comparison of mean STT values between right ( n = 20) and left eyes ( n = 20) showed no differences ( P = 0.88). Mean (SD) IOP values by applanation tonometry were 9.37 ± 2.45 mmHg (range 6–14.5 mmHg). Comparison of mean IOP values between right ( n = 20) and left eyes ( n = 20) showed no differences ( P = 0.59). In conclusion, this study reports STT and IOP findings in Sanjabi sheep, and provide means and ranges for IOP and STT.