Distichiasis causing recurrent corneal ulceration in two Friesian horses

Two cases of distichiasis with subsequent recurrent superficial corneal ulceration are described in Friesian horses. Case 1 was a 9‐year‐old Friesian stallion with distichiae on the superior and inferior eyelids of both eyes corresponding to areas of recurrent superficial corneal ulceration. Case 2 was a 5‐year‐old Friesian gelding with a single distichia on the inferior lid associated with recurrent superficial corneal ulceration in the right eye. Case 1 underwent cryotherapy and epilation twice under standing sedation without resolution of distichiasis. A partial tarsal plate excision was then performed on the inferior left lid, which was the most severely affected. Cryotherapy was repeated one and 4 months post operatively due to recurrence. Cryotherapy was associated with skin depigmentation and repigmentation several months following the procedure. No recurrence has been reported up to 3 years following the fourth cryotherapy procedure. Case 2 was treated with epilation. Distichiasis should be included as a differential diagnosis when presented with a horse experiencing recurrent superficial corneal ulcerations. There has been no established breed association for Friesian horses and distichiasis but, due to the inherited nature of this condition in some human patients and dogs, this possibility should be investigated.