Bullous keratopathy treated with a nictitating membrane flap

A bulla is a large blister. Bullous keratopathy is not a common presentation for infected, inflamed eyes in horses. There is remarkable swelling and edema (cloudiness) of the anterior surface of the cornea, with stromal ulceration underneath. Pseudomonas is believed to be a cause but in this study, one of the two horses had a fungal organism cultured out of the lesion.
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Abstract
Objective
The aim of this study was to describe placement of a nictitating membrane flap as a treatment for corneal ulceration and bullous keratopathy in two horses.

Animals Studied
A 13-year-old American Saddlebred mare presented for severe corneal edema, superficial stromal ulceration, and a central bulla of the left eye. A 4-year-old Trakhener stallion also presented with a large axial bulla of the left eye with concurrent severe corneal edema and a deep stromal ulcer.

Procedure
A complete ophthalmic examination was performed. Samples were obtained for corneal cytology, and both horses were started on aggressive medical therapy. Both underwent general anesthesia for placement of a nictitating membrane flap and a subpalpebral lavage system (SPLS).

Results
Corneal cytology for each horse revealed a mixed bacterial population. Moderate Pseudomonas aeruginosa was cultured from the mare, while Aspergillus species and a few Enterococcus gallinarum were cultured from the stallion. The bullae in both horses resolved at 3 and 4 weeks and vision returned in the affected eye 4.5 and 3 months postoperatively at the last follow-up, respectively.

Conclusion
Aggressive medical management with concurrent placement of a nictitating membrane flap is effective to treat bullous keratopathy in two horses. The described treatments could be used to treat horses that develop severe or progressive bullous corneal lesions.