Hornhautödem vermutlich endothelialen Ursprungs bei fünf Pferden: Diagnostik, oberflächliche Keratektomie und Gunderson-Flap sowie vorläufiges Resultat

Corneal oedema in the adult horse can be caused by multiple problems such as glaucoma, uveitis, iridocyclitis and keratitis, endothelial disease or trauma. This retrospective clinical case study describes five horses with severe local band shaped or diffuse corneal oedema of suspected primary endothelial origin treated with a superficial keratectomy and Gunderson inlay flap. The value of ultrasound as an advanced imaging modality in order to ensure correct diagnosis and therefore proper case selection is also described. Case records of horses admitted for diagnosis and treatment of unilateral band shaped or diffuse corneal oedema between May and October 2020 were reviewed and five horses were included. Patient details, clinical history, ophthalmic and ultrasonographic examination results, treatment and clinical outcome and follow-up after surgery were recorded. Ophthalmic and ultrasonographic examination showed corneal oedema of endothelial origin. By performing ultrasound other possible causes for severe corneal oedema could be considered less likely. However, in 1 horse signs of previous uveitis were seen. Previous medical treatment generally consisted of topical corticosteroids but was unsuccessful in all cases. Surgical treatment in all 5 horses consisted of superficial keratectomy and a Gunderson inlay flap. Mild ocular discomfort was seen in 2 out of 5 horses (Case 2 and 5) the first week after surgery. One horse (Case 3) showed severe ocular discomfort the first 2 weeks after surgery which was suspected to be due to anterior uveitis. One horse (Case 4) suffering from chronic uveitis prior to surgery resulting in increased intra-ocular pressure is still dependent on topical medication. Two horses had a methicillin resistant Staphylococcus aureus (MRSA) on bacterial culture and sensitivity testing, one horse postoperatively and one pre-operatively. The follow-up period varied between 2 to 7 months. At time of follow-up, all horses showed a reduction in corneal oedema, had no signs of ocular discomfort and had retained vision. In conclusion, horses with corneal oedema of endothelial origin may benefit from a superficial keratectomy and Gunderson inlay flap. If medical treatment fails to reduce the corneal oedema, this surgical treatment shows promising preliminary results. Culture and sensitivity testing prior to performing corneal surgery might be useful. Ultrasonographic examination could aid in differential diagnoses prior to surgery and prognosis. Further research is warranted.