Effect of Topical Cyclopentolate 1% on Ocular Ultrasonographic Features, Intraocular Pressure, Tear Production, and Pupil Size in Normal Donkeys (Equus Asinus).
Authors: Hussein Kamal Hany, Elmeligy Enas, Khalphallah Arafat, Al-Lethie Al-Lethie A
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Cyclopentolate Effects in Donkey Ophthalmology Cycloplegic agents remain essential diagnostic tools in equine practice, yet their pharmacological effects have been poorly characterised in donkeys despite their widespread use across diverse equine species. Researchers administered topical cyclopentolate 1% to one eye of eight clinically healthy donkeys whilst the contralateral eye received saline control, measuring ultrasonographic changes to anterior chamber structures, intraocular pressure (IOP), tear production via Schirmer tear test, and pupil diameter over a 2-hour period. Cyclopentolate significantly widened both the iridocorneal angle and ciliary cleft entrance on ultrasound, induced mydriasis (peak dilation occurring 30–120 minutes post-instillation), and elevated IOP between 30–60 minutes post-application, yet did not compromise tear production compared to controls. For practitioners using cyclopentolate in donkey ophthalmoscopy or refraction work, these findings suggest the agent is well-tolerated without systemic adverse effects, though the transient IOP elevation warrants monitoring in patients with pre-existing glaucoma or ocular hypertension, and the mydriatic effect should be anticipated when scheduling procedures requiring accommodation assessment.
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Practical Takeaways
- •Cyclopentolate 1% is an effective cycloplegic agent for donkeys with no reported systemic or ocular side effects, useful for ophthalmic examinations requiring pupil dilation and cycloplegia
- •Expect mydriasis and cycloplegia onset within 30 minutes of instillation; monitor IOP in treated eyes as pressures increase during this 30-60 minute window
- •Tear production remains stable with cyclopentolate use in donkeys, making it suitable for animals where tear film integrity is a concern
Key Findings
- •Cyclopentolate 1% significantly increased iridocorneal angle and ciliary cleft width on ultrasonography in donkeys
- •Intraocular pressure increased significantly from 30-60 minutes post-instillation with cyclopentolate 1%
- •Pupil diameters (vertical and horizontal) significantly increased at 30 minutes post-instillation with cyclopentolate 1%
- •No significant changes in tear production (STT) were observed with cyclopentolate 1% treatment