Retinopathy of Coton de Tulear dogs: clinical manifestations, electroretinographic, ultrasonographic, fluorescein and indocyanine green angiographic, and optical coherence tomographic findings.

Abstract

OBJECTIVES: To document the clinical manifestations, development, progression, and mode of inheritance of the retinopathy of Coton de Tulear dogs. MATERIALS AND METHODS: Multiple Coton de Tulear dogs were examined with biomicroscopy, indirect ophthalmoscopy, photopic and scotopic electroretinography, fluorescein and indocyanine green angiography, optical coherence tomography, ultrasonography, and fundic photography for 3 years. RESULTS: The retinopathy of Coton de Tulear dogs is inherited as an autosomal recessive condition and manifests as multifocal serous retinal detachments in homozygous puppies, between 3 and 4 months of age. Optic coherence tomography and ultrasonography confirm multiple focal serous retinal detachments. Serial fundic photographs confirmed minimal progression of lesions beyond 1 year of age. Electroretinography identified diminished scotopic and photopic amplitudes; however, the only significant differences between affected and age-matched control Coton de Tulear dogs were noted during photopic flicker electroretinograms. Leakage of fluorescein or indocyanine green through the blood ocular barriers was not detected during repeated angiograms prior to, during, and after development of the retinopathy. There was no focal pooling of fluorescein in any of the dogs examined. Focal retinal thinning was detected with optical coherence tomography over each detachment and the serous content of some of the bullae diminish after several years leaving focal areas of hyper-reflectivity. CONCLUSIONS: Multifocal retinopathy of Coton de Tulear dogs is inherited as an autosomal recessive condition. The retinopathy manifests early in life as nonprogressive multifocal bullous retinal detachments. The blood ocular barrier remains intact. Photopic and scotopic electroretinography are minimally diminished compared to age-matched dogs.