THERAPEUTIC OPTIONS FOR CORNEAL CONDITION COMPARED

New research from the University of California–Davis suggests that topical medications and surgery can both be effective in treating a painful eye condition called eosinophilic keratoconjunctivitis (EK)—though use of topical corticosteroids was associated with longer healing times.

In EK, a type of white blood cell called eosinophils accumulate in the cornea, the normally clear “windshield” of the eye. While the cause is unknown, EK cases are most often diagnosed in summer months, suggesting environmental factors may contribute to the condition. EK, which causes discomfort and visual impairment, can be difficult to treat, sometimes persisting for several months. It is also associated with secondary infections.

For their study, the Davis researchers reviewed the records of 29 horses diagnosed with EK. Twenty of the study horses were treated with medications alone, receiving topical antimicrobials, topical nonsteroidal antiinflammatory medications, topical corticosteroids, topical antihistamines and various systemic medications. The remainder of the horses underwent surgical procedures in addition to medical treatment, including the excision of the affected portion of the cornea (keratectomy), or debridement of the affected area with an ophthalmic diamond burr.

The researchers found no statistically significant difference in the median time required for healing between the horses treated with a keratectomy or debridement and horses treated with medical therapy alone. However, horses treated with topical corticosteroids had significantly longer healing times compared to those who did not receive topical steroids.

Although it is difficult to compare across studies, times to disease resolution for horses in California seem shorter than for horses affected with EK in other parts of the United States, suggesting regional differences in disease severity.

Reference: “Equine eosinophilic keratoconjunctivitis in California: Retrospective study of 47 eyes from 29 cases (1993-2017),” Veterinary Ophthalmology, January 2019