Continuous ophthalmic treatment using an osmotic pump in a bull calf following surgical removal of an ocular dermoid: a case report

An intact male, six-month-old Hanwoo bull calf (native Korean beef breed) was presented to the Animal Medical Centre, Chonbuk National University because the owner had noticed a conjunctival and corneal abnormality in the left eye (OS). On ophthalmic examination, a small, elevated and skin-like mass lesion, containing hair was found on the ventronasal cornea and the conjunctiva of the third eyelid. In the light of its characteristic appearance, the lesion was classified clinically as a corneal dermoid. Under general anaesthesia, superficial lamellar keratectomy and conjunctivectomy was performed to remove the abnormal tissue. As the owner could not apply topical medications regularly, a drug-filled osmotic pump (Alzet; Alza, Palo Alto, CA) was implanted subconjunctivally under the upper eyelid and connected to a catheter at the lateral limbus. The catheter was fixed to the conjunctiva with 3-0 polyglactin 910 (Vicryl®; Ethicon, Johnson and Johnson, Somerville, USA) and a partial temporary tarsorrhaphy was placed. In order to determine the efficacy of medication delivery, a sample of aqueous humour was collected via aqueocentesis from the anterior chamber at two weeks and four weeks after implantation of the pump. The presence and concentration of ciprofloxacin was determined via mass spectroscopy. Aqueous concentration of ciprofloxacin was 0.093 µg/ml at two weeks and 0.107 µg/ml at four weeks. The calf healed without incident and returned to normal function six weeks following the procedure.