Diagnostic ophthalmology. Corneal ulcer with severe secondary anterior uveitis in a pony.

The study reports on the diagnosis and treatment of a severe case of corneal ulceration and anterior uveitis in a 1-year-old Norwegian fjord pony, which did not respond to initial treatments, highlighting the medical and ophthalmological procedures carried out to manage the conditions.

Case Presentation

• A 1-year-old female Norwegian fjord pony, who had shown symptoms of corneal ulceration in the right eye for 10 days, was brought to the ophthalmology service at the Western College of Veterinary Medicine. Initial treatments with topical triple antibiotic ointment and a mix of topical chloramphenicol and atropine solution administered through a subpalpebral lavage system did not improve the condition.

Physical Examination

• While the general physical examination did not reveal anything unusual, the right eye of the pony was notably painful. This was evident due to blepharospasm, a condition causing involuntary tight closure of the eyelids, and the overflow of tears, known as epiphora.
• A neuro-ophthalmic examination revealed nullified direct and consensual pupillary light reflexes in the right eye. To facilitate a more thorough examination of the eye, the pony was sedated and an auriculopalpebral nerve block was administered.

Subsequent Findings

• Examination with a transilluminator and a slit lamp biomicroscope revealed a large, round, pale yellow gelatinous region covering about two-thirds of the corneal surface. Notably, it extended inward to about 40% of the corneal stromal depth.
• Different degrees of corneal edema and corneal vascularization were observed around the entire limbal area and extended 2 mm into the corneal surface.
• A pronounced turbidity of the aqueous humor (aqueous flare), contraction of the pupil (miosis), the presence of white blood cells in the anterior chamber (hypopyon occupying the bottom 25% of the anterior space), and fibrin in the anterior chamber of the right eye were significant findings. These suggested a severe anterior uveitis secondary to the corneal ulceration.