Punctate fluorescein staining scores in dogs with or without aqueous tear deficiency

Objective To compare the superficial punctate fluorescein staining in dogs with and without aqueous tear deficiency. Procedures An eye from each client‐owned dogs presented to Triangle Animal Eye Clinic between January and December 2018 underwent tear and ocular surface tests, which included the Schirmer tear test (STT), phenol red thread test (PRT), and strip meniscometry tube tear test (SMT). Punctate fluorescein staining of the cornea (PFS‐C) and the upper palpebral conjunctiva (PFS‐UPC) were also performed. Fifty‐seven dogs with STT results of <15 mm/min had aqueous tear deficiency (AD); 31 dogs had <10 mm/min and 26 dogs had ≥10 mm/min. The 162 dogs with STT results of ≥15 mm/min did not have AD. The test results of the groups were compared using Kruskal‐Wallis and Steel‐Dwass multiple comparison tests. Results Two hundred and nineteen eyes from 219 dogs were enrolled in this study. The PRT and SMT results, presented as mean ± SD, were significantly lower in the AD group than in the non‐AD group (PRT: 29.5 ± 8.1 vs 36.9 ± 5.6 mm/15 s; SMT: 6.2 ± 3.8 vs 10.8 ± 2.8 mm/5 s). The PFS scores were significantly higher in the AD group than in the non‐AD group (PFS‐C: 4.4 ± 0.7 and 3.7 ± 0.8; PFS‐UPC: 2.3 ± 0.5 and 1.7 ± 0.5). Conclusions These results suggest that aqueous tear deficiency is not only reflected by PRT and SMT but also PFS‐C and PFS‐UPC.