Systemic Ivermectin Administration Reduces Aqueous Tear Production and Affects Ocular Surface Health in Clinically Healthy Dogs.

Ivermectin reduces tear production; recommend STT-I monitoring in treated dogs.

This controlled study evaluated the effects of systemic ivermectin on tear production and ocular surface health in 128 clinically healthy mixed-breed dogs (64 treated, 64 controls). Using Schirmer tear test I (STT-I), fluorescein staining, and corneal opacity scoring, researchers found that ivermectin significantly reduced aqueous tear production at 36 hours post-treatment. The ivermectin-treated group showed a mean reduction of -4.38 mm/min compared to -0.14 mm/min in controls. Mean STT-I values were substantially lower in treated dogs (6.05 mm/min) versus controls (10.08 mm/min). Fluorescein uptake indicating corneal surface damage occurred in 32.8% of treated dogs versus 7.8% of controls. Keratoconjunctivitis sicca severity scores were significantly elevated in the ivermectin group. While the mechanism remains undefined, the authors suggest potential involvement of altered neural control of lacrimal secretion. These findings suggest that even at recommended doses, ivermectin may predispose susceptible dogs to subclinical dry eye, warranting routine tear testing in dogs receiving ivermectin prophylaxis.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.