Bilateral corneal dermoids associated with bilateral choroido–scleral colobomas in a cat: retinographic and optical coherence tomography study with surgical outcome and follow–up

Purpose To report a case of feline bilateral corneal dermoids, associated with unilateral iris coloboma and bilateral choroido‐scleral colobomas in the same dorsolateral position, to describe retinographic and optical coherence tomography (OCT) characteristics, surgical outcome, and follow‐up. Animal studied A 9‐month‐old domestic shorthaired cat in which a full ophthalmoscopic examination was performed for evaluation of dermoids resulting in a diagnosis of associated iris coloboma in one eye and posterior colobomas in both eyes. Procedures Retinographies and OCT were performed under anesthesia to characterize the lesions of both fundi and allow surgical excision of the corneal dermoids. Results Ophthalmoscopy and retinographies revealed oval lesions in the dorsolateral fundi of both eyes. The lesions precisely mirrored their respective dermoids' (10‐11 h OD and 1‐2 h OS) clock positions, lacked a tapetum lucidum and choroidal vessels, and featured thin retinal vessels plunging to a posterior plane of the fundus. OCT crossline scans demonstrated preservation of retinal thickness and morphological layering in the fundic colobomas leading to the conclusion that the colobomas were purely choroido‐scleral. The outcome of the surgical excision of the dermoids was satisfactory without hair recurrence and with acceptable corneal clarity making it possible to visualize the unilateral associated iris coloboma. Follow‐ups did not reveal any fundic evolution nor retinal detachment. Conclusions Retinographies and OCT made possible the characterization of choroido‐scleral colobomas associated with corneal dermoids in this first reported case in a cat. We hypothesize that the recently described superior ocular sulcus might be the embryological link between these anomalies.