Effect of topical ophthalmic latanoprost 0.005% solution alone and in combination with diclofenac 0.1% solution in healthy horses: a pilot study.

This study examines the effects of eye drops containing latanoprost and diclofenac, individually and in combination, on the eyes of healthy horses. The findings show that latanoprost successfully lowers intraocular pressure (IOP), with diclofenac helping to alleviate related discomfort.

Study Design and Methodology

• The experiment revolves around twelve adult horses which are randomly assigned to three different groups, each group receiving a different type of eye-drop treatment.
• The first group, Group D, is given eye drops of 0.1% diclofenac, while the second group, Group L, receives 0.005% latanoprost.
• The third group, Group DL, is treated with both 0.005% latanoprost and 0.2 ml of 0.1% diclofenac simultaneously.
• This initial study setup, referred to as “arm 1”, is followed by a phase called “arm 2” where horses from Group D and L are combined into Group DL and horses from group DL are divided either into Group D or group L.

Evaluation Parameters and Findings

• Several parameters like intraocular pressure (IOP), vertical pupil diameter, aqueous flare, conjunctival hyperemia, epiphora (excessive watering of the eyes), blepharospasm (involuntary twitching of the eyelid), and blepharoedema (swelling of the eyelid) were meticulously monitored at fixed intervals.
• The study found that between the two treatment arms, there was a significant reduction in IOP and vertical pupil diameter in the eyes treated with latanoprost (Groups L and DL) compared to the eyes treated with diclofenac alone (Group D).
• Interestingly, however, latanoprost-induced discomfort as measured by blepharospasm, blepharoedema, epiphora, and conjunctival hyperemia was noticeably greater in Group L than in Groups D and DL.

Conclusion

• The study concludes that latanoprost effectively reduces IOP in healthy horses. However, it also causes discomfort which can be significantly mitigated by the concurrent administration of diclofenac.
• This finding could have important implications for the management of equine glaucoma, to help prevent increased IOP that can adversely affect the horses’ vision.