Immediate Effect of Three Artificial Tear Formulations on Tear Film Osmolality in Brachycephalic Dogs

To investigate the effects of three sodium hyaluronate-based artificial tear formulations on tear film osmolality (TFO) in brachycephalic dogs.

Forty healthy brachycephalic dogs were evaluated.

TFO was measured using the I-PEN VET osmometry system. Dogs were assigned to four groups. Dogs in Groups 1, 2, and 3 received one drop of artificial tear containing 0.4% sodium hyaluronate, artificial tear containing 0.9 mg sodium hyaluronate and vitamin B12 in 0.5 mL, and artificial tear containing 1.6 mg hyaluronate in 0.5 mL, respectively. Dogs in Group 4 served as controls and received one drop of sterile water for injection. Tear osmolality was measured 10 min after instillation of the eye drop. Statistical analysis was performed using SPSS software.

Mean (SD) TFO at the initial examination was 307.4 (35.8), 299.4 (12.0), 318.2 (34.3), 307.2 (12.0) mOsm/L in Groups 1-4, respectively. Ten minutes after instillation of artificial tears, TFO was decreased by 53.4 mOsm/L (17.3%), 17.6 mOsm/L (5.8%), 31.8 mOsm/L (9.9%) and 3.4 mOsm/L (1.1%), respectively. Significant decreases were observed in Groups 1-3 (p = 0.016, 0.021, 0.038). Intergroup comparison revealed significant differences in mean TFO between Groups 1 and 4 (p = 0.006).

This study demonstrated a significant immediate reduction of TFO with HA containing artificial tears in brachycephalic dogs. Artificial tears containing 2 mg of sodium hyaluronate in 0.5 mL (0.4%) had the most significant effect. Further studies are warranted in a large group of dogs with dry eye disease.