BackgroundThe objective of this study was to evaluate the effectiveness of various linseed oil (LO) preparations (oral, topical, oral and topical combined) in treating experimentally induced keratoconjunctivitis sicca (KCS) in rabbits. Twenty male New Zealand white rabbits were divided into four groups: group C (control), group OLO (oral LO), group TLO (topical LO), and group OTLO (oral and topical LO). The animals were evaluated weekly using Schirmer's tear test (STT), fluorescein test (FT), and Rose Bengal test (RBT) and were euthanized at the end of the experiment for histopathological analysis.FindingsThere were significant improvements in the parameters analyzed (STT, FT, and RBT) and in the histopathological finding in all of the groups using LO.ConclusionsThe analyzed results demonstrate that LO, administered orally or topically, was effective in treating experimentally induced KCS in rabbits, although combined oral and topical LO did not show additional benefits greater than those with a single route of administration.

In sum, 0.03% tacrolimus eye drops diluted in olive oil and linseed oil were effective in the treatment of keratoconjunctivitis sicca. None of the evaluated parameters differed significantly between the two groups, except for neutrophil count which was significantly lower in the TL group. Thus, linseed oil may be considered as an alternative diluent for tacrolimus eye drops.

To compare strip meniscometry and Schirmer tear test 1 results and tear film breakup time between dogs with normal eyes and dogs diagnosed with keratoconjunctivitis sicca. Methods: One-hundred fifty-six eyes of 78 dogs, 88 normal eyes, and 68 eyes diagnosed with keratoconjunctivitis sicca were included in the study. The tests were performed in the following sequence: Schirmer tear test 1 was used to allocate the dogs to the normal or keratoconjunctivitis sicca group, followed by the strip meniscometry test and tear film breakup time measurement. Results: The results (mean ± standard deviation) of the tests in the normal group were as follows: Schirmer tear test 1, 22.75 ± 3.88 mm/min; strip meniscometry test, 10.01 ± 2.35 mm/5 sec; and tear film breakup time, 25.82 ± 5.47 sec. In the keratoconjunctivitis sicca group, the results were as follows: Schirmer tear test 1, 6.10 ± 4.44 mm/min; strip meniscometry test, 3.03 ± 2.62 mm/5 sec; and tear film breakup time, 10.78 ± 4.23 sec. The Spearman correlation coefficient in the keratoconjunctivitis sicca group was very high, with a significant difference between the strip meniscometry test and Schirmer tear test 1 (r=0.848, p<0.001), and moderate and significant between the strip meniscometry test and tear film breakup time (r=0.773, p<0.001). The cutoff for the strip meniscometry test for keratoconjunctivitis sicca was 7.0 mm/5 sec. Keratoconjunctivitis sicca was suspected when the values were <10 mm/5 sec. Conclusions: This study provided strip meniscometry test values from dogs with normal eyes and eyes with keratoconjunctivitis sicca, with high sensitivity and specificity compared with those of the Schirmer tear test 1. In the future, the strip meniscometry test may be another important quantitative test and could complement the gold standard Schirmer tear test for the diagnosis of keratoconjunctivitis sicca in dogs, an excellent animal model for the study of the disease.