Purpose
To examine the in vivo retinal microanatomy characteristics of dogs with different forms of focal/multifocal/geographic retinal dysplasia.
Methods
Five working service dogs were studied because of retinal abnormalities found in routine ophthalmic examinations. There were 4F/1M (3 Labrador retrievers, 2 German shepherd) in the 1.2-2 yr age range. In 3 cases a circular golden plaque was observed in one or both eyes; in 1 case bilateral dark branching retinal folds were present above the optic nerve head, and in 1 case an incomplete ring of retinal folds was present unilaterally. In-vivo retinal microanatomy was evaluated under general anesthesia by non-invasive imaging with a Spectralis cSLO/SD-OCT instrument. The cSLO images were taken using the near-infrared (IR), red-free (RF) and auto fluorescence (AF) modes. The sd-OCT images were acquired as raster scans (9 ART) or single scan (20 ART).
Results
Indirect ophthalmoscopy in 3 dogs showed irregular round plaques in tapetal area with a change in reflectivity, and surrounding retinal folds consistent with geographic retinal dysplasia. The other 2 cases had retinal folds consistent with multifocal retinal dysplasia. cSLO images in IR mode showed hypo reflective areas and all geographic lesions were fluorescent in AF mode. sd-OCT from the geographic lesions showed a disorganized inner retina and retinal folds only at the edges. In the multifocal form, sd-OCT showed only retinal folds and no other abnormalities in retinal structure.
Conclusions
The term retinal dysplasia has been used to group a variety of retinal fundus findings in dogs characterized by retinal folds, or rosettes on tissue sections. As many of these are not present congenitally, and, at least for geographic retinal dysplasia, are characterized by inner retinal changes and not retinal folds, we suggest that a different term for the disorder be considered.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
688 retina