Effect of Topical Cyclopentolate 1% on Ocular Ultrasonographic Features, Intraocular Pressure, Tear Production, and Pupil Size in Normal Donkeys (Equus Asinus).

The research article investigates the effects of the drug cyclopentolate (in a 1% solution) on various aspects of donkey eye health, through metrics such as eye structure, intraocular pressure, tear production, and pupil size. It concludes that cyclopentolate can increase certain eye parameters in donkeys without negative side effects.

Study Setup

• The study involved sixteen eyes from eight healthy adult donkeys aged between 2 and 2.5 years, and having an average weight of 295 kg.
• One eye of each donkey was treated with cyclopentolate hydrochloride 1%, while the other eye received normal saline drops as a control.

Measurement Methods

• The researchers used ultrasonography to assess the effects of cyclopentolate on the donkey’s eye structures.
• The intraocular pressure and tear production were measured for 2 hours post-instillation using tonometry and the Schirmer tear test (STT), respectively.
• Changes in vertical and horizontal pupil diameters were recorded before and at several intervals (15, 30, 45, 60 and 120 minutes) post-instillation.

Findings

• Ultrasonography revealed that cyclopentolate significantly increased the iridocorneal angle and width of the entry of the ciliary cleft, components of the eye related to fluid drainage and pressure regulation.
• Intraocular pressure was notably elevated between 30 to 60 minutes after applying cyclopentolate 1%.
• No significant change in tear production was observed in the cyclopentolate-treated eyes compared to the control eyes.
• Both the vertical and horizontal pupil diameters began to significantly increase 30 minutes after cyclopentolate 1% instillation compared to the control saline group.

Conclusions

• The researchers concluded that cyclopentolate 1% could serve as an effective cycloplegic drug (one used to temporarily paralyze the muscles that control the accommodation and focus parameters of the eyeball) in donkeys without any associated systemic or ocular side effects.