Differential diagnoses for a painful vascularized corneal lesion include an indolent ulcer with granulation tissue, a stromal ulcer with granulation tissue, a corneal abscess or foreign body, or an immune-mediated process such as pannus. In this dog, the irregular corneal contour is most consistent with ridges of nonadherent epithelium, prioritizing the first of these differentials.
Indolent ulcers occur when epithelium fails to adhere to underlying stroma following superficial injury. They involve the epithelium only, and do not extend into the stroma. Key features include flaps or folds of nonadherent epithelium, hyalinization of the underlying stroma, and variable degrees of neovascularization and discomfort. Etiology for the failure of adherence between the epithelium and stroma is unclear. Although idiopathic indolent ulcers are common in Boxers, one must still rule out potential contributing causes, including keratoconjunctivitis sicca, entropion, distichiasis, ectopic cilium, and foreign body. A Schirmer tear test should be performed, and the eyelids, bulbar and palpebral conjunctiva, and posterior surface of the third eyelid should all be inspected as part of a complete ophthalmic examination.
In this dog, Schirmer tear test values were normal. Faint fluorescein uptake was seen overlying the lesion. Inspection of the dorsal palpebral conjunctiva revealed a small nodule coated in mucus (figure 2). Removal of the mucus exposed an ectopic cilium.
Management of indolent ulcers depends on addressing underlying causes and making interventions to promote healing. In the case of this dog the following steps were taken
- She was anesthetized, the ectopic cilium was excised, and the area was treated with cryotherapy.
- The ulcer was debrided with a diamond burr tool and a bandage contact lens was placed.
- She was sent home with topical tobramycin and artificial tears to be used 3 times a day, along with oral doxycycline (5 mg/kg twice a day) and gabapentin (~8 mg/kg 2-3 times a day as needed). An Elizabethan collar was to be worn at all times.
On examination 2 weeks later, the ulcer was fully healed, with minor fibrosis and neovascularization present (figure 3). The contact lens was removed and medications were discontinued.