Effects of Tafluprost on Equine Eyes

Study Objective

• The study seeks to determine tafluprost's effects and side effects in normal equine eyes.

Study Details

• Five adult horses were used.
• One eye was randomly selected for treatment, and the other eye served as the control.
• A single dose of preservative-free (PF) tafluprost 0.0015% (0.2 mL) was used.
• Intraocular pressure (IOP) and Schirmer's tear test (STT) levels were measured along with ophthalmic examinations conducted at baseline (T0), 30 min (T30), 120 min (T120), 24 h (T24 h), and 48 h (T48 h).

Results of the Study

• The mean IOP values in the treated eyes were:
  • 25.4 ± 4.8 mmHg at baseline (T0)
  • 21.2 ± 1.92 mmHg at T30
  • 15.20 ± 2.48 mmHg at T120
  • 18.40 ± 1.51 mmHg at T24 h
  • 24.60 ± 1.94 mmHg at T48 h
• Significant differences in IOP were noted between baseline and T120/T24.
• STT levels showed statistically insignificant fluctuations (p = .140).
• Chemosis and episcleral injection were observed 30 minutes after tafluprost instillation.
• Blepharospasm and conjunctival hyperemia were noted 120 minutes post-administration.

Conclusion

• Tafluprost 0.0015% has the potential to lower IOP.
• The findings suggest it is not an ideal glaucoma treatment for horses because of local side effects.
• Tafluprost did not significantly impact STT levels.

Introduction to Glaucoma

• Equine glaucoma often results from other ocular issues like uveitis or lens luxation.
• Primary glaucoma is rare.
• Medical and surgical approaches aim at reducing primary IOP.
• Topical beta-blockers and carbonic anhydrase inhibitors can be effective.

Tafluprost Information

• Tafluprost 0.0015% is a fourth-generation prostaglandin analog (PGA).
• It has shown IOP-lowering effects in dogs within 4 hours post-instillation.
• It can improve retinal blood flow.

Materials and Methods Used

• Inclusion criteria included healthy adult mixed-breed horses aged two years or older, without a history of ophthalmic complications or sport activity for one week.
• Eye measurements were taken at 30 min (T30), 120 min (T120), and 24 h (T24 h) after initial tafluprost instillation, then every 24 h until Day 21.
• Ten eyes from five mares were used, and no sedatives or nerve blocks were used.
• Ophthalmic examinations included slit-lamp biomicroscopy, direct and indirect ophthalmoscopy, fluorescein staining, STT, and tonometry to measure IOP.

Local Side Effects

• Ocular discomfort has been reported following topical latanoprost use.
• In humans, latanoprost has local side effects in 5%–15% of patients but tafluprost between 4%-20%.

Concurrent Use of NSAIDs

• In human studies, NSAIDs alleviate PGA side effects, though results vary.
• In horses, diclofenac with latanoprost has been tested.
• Future studies of diclofenac and tafluprost in horses with and without glaucoma are recommended.

Additional Findings

• Tafluprost significantly lowered IOP at 120 minutes post-administration, with this effect lasting 24 hours.
• At two hours post-instillation, mean IOP was reduced by 10.2 mmHg.
• In one horse, IOP decreased by 14 mmHg compared to baseline.

Pupil Diameter

• Miosis induction with tafluprost began after 2 hours and lasted until 24 hours postinstillation.
• Latanoprost was reported to induce miosis 4-8 hours post instillation.
• The mean pupil diameter decreased by 72% after 120 minutes in treated eyes, returning to baseline after 48 hours. A topical dose of tafluprost had no systemic effects shown in IOP/Pupil Diameter of the control eyes.

Additional Research

• Tafluprost is shown to prevent neuropathy progression; one study promoted retinal ganglion cell survival in rats.
• Long-term use enhances retinal blood flow.

Study Limitations

• The experiment involved a small number of horses.
• The adverse effects made the authors stop the study
• Future tests using anti-inflammatory drugs with tafluprost are advised.