Atypical chorioretinal coloboma in a Golden Retriever: a retinographic, fluoroangiographic, and optical coherence tomography study

PURPOSE: To report a case of canine atypical chorioretinal coloboma where ophthalmoscopic, fluoroangiographic and optical coherence tomography characteristics are described. ANIMAL STUDIED: A 2-year-old Golden Retriever dog in which routine ophthalmoscopic examination allowed diagnosis of a posterior coloboma on the left eye. PROCEDURES: Retinography, fluorescein angiography, and optical coherence tomography were performed to characterize the lesion of the left fundus. RESULTS: Ophthalmoscopy revealed a pigmented circumscribed lesion dorsal to the optic nerve of the left fundus, surrounded by small areas of hyper-reflectivity and retinal vessels with an abnormal pattern. Fluoroangiography revealed a constant hypofluorescence of the defect and a complete altered vascular pattern associated with the coloboma. Optical coherence study demonstrated an important craterlike depression showing an atrophic neurosensory retina, and a lack of retinal pigment epithelium and choroidal tissue. CONCLUSIONS: Fluoroangiographic and optical coherence tomographic studies of an atypical chorioretinal coloboma in a dog are reported for the first time. Both imaging techniques are of great importance to characterize this type of congenital defects.