Episcleral cyclosporine A implants for the management of unilateral keratoconjunctivitis sicca in an 8-year-old mare.

This research studies the use of cyclosporine A implants in treating a mare suffering from keratoconjunctivitis sicca (KCS), a dry eye condition. The study suggests that the implant was beneficial, improving the mare’s condition without any recurring symptoms during the year-long follow-up.

Background on Keratoconjunctivitis Sicca

• Keratoconjunctivitis sicca, often referred to as ‘dry eye,’ is a condition characterized by a reduction in tear production.
• This can result in noticeable symptoms such as blepharospasm (involuntary twitching of the eyelid), eyelid swelling, corneal edema (swelling of the cornea of the eye), and a constant ocular discharge.
• It was these symptoms that brought the 8-year-old mare to the attention of the researchers in the first place.

Treatment With Cyclosporine A

• Cyclosporine A is a medication known for its immunosuppressive properties which can be used topically to treat KCS.
• After confirming the mare’s KCS condition by a Schirmer tear test (a test measuring tear production), topical 0.2% cyclosporine A was applied to the mare’s right eye.
• The initial cyclosporine treatment resulted in an improvement in the mare’s symptoms.

Use of Cyclosporine A Implants

• Five days after the initial presentation, an episcleral cyclosporine A implant was inserted into the mare under standing sedation.
• This method was selected to provide a sustained release of the drug and ensure continuous treatment of the mare’s KCS.
• A re-examination of the mare nine days later confirmed that the implant was successful; not only did the mare’s tear production improve, but no further clinical signs of KCS were observed.

Long-Term Results and Implications

• The mare was monitored for up to 12 months after the implantation surgery, with no recurrence of clinical symptoms or notable side-effects being observed during this period.
• As a result, this study becomes the first to report the use of a cyclosporine A implant in the management of KCS in a horse.
• This pioneering step in equine ophthalmology suggests that cyclosporine A implants offer a potential alternative therapy in the management of KCS in horses.