Radiotherapy for canine chronic superficial keratitis using soft X-rays (15 kV)

Abstract

Objective: To evaluate the effect of soft X-ray therapy in the treatment of refractory chronic superficial keratitis (CSK).

Animals studied: Thirteen dogs with severe CSK, that had been refractory to prior medical and/or surgical therapy were treated with soft X-ray therapy.

Procedures: Both corneas of each dog were irradiated with soft X-rays (15 kV), to a total dose of 30 Gy, administered as two fractions over 48-96 h. Treatment was carried out under deep sedation in all dogs. Three dogs were treated by superficial lamellar keratectomy 48 h prior to radiotherapy. Changes in the extent of corneal pigmentation, pigment density and corneal vascularization were documented using a semi-quantitative grading scheme, schematic drawings and clinical photographs.

Results: Only minor, transient adverse effects of treatment, such as photophobia, epiphora and blepharitis were noted. Overall the effect of soft X-rays on the course of the keratitis was superior when compared to the effect of Sr-90 irradiation that had been determined in a previous study.

Conclusion: Soft X-ray irradiation combined with keratectomy is a safe and effective new treatment option for severe and advanced CSK with significant visual impairment due to corneal pathology.