In vivo imaging comparison of unilateral circular retinal plaques in retriever dogs to dysplasia and detachment in the English Springer Spaniel

Abstract

Purpose To compare the scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), and fluorescein angiography (FA) findings in retrievers with a single unilateral circular retinal plaque to those of an English springer spaniel with bilateral retinal dysplasia. Procedures A retrospective record review identified three dogs with circular retinal plaques that underwent SLO and OCT; in two of the three dogs, FA was also completed. Morphologic changes, lesion measurements, and angiogram characteristics were documented. An English springer spaniel with bilateral retinal dysplasia that had undergone SLO, OCT, and FA was used for comparison. Results Scanning laser ophthalmoscopy of the retriever dogs revealed circular retinal plaques with a dark periphery located in the tapetal retina. OCT revealed a thickening of the nerve fiber layer corresponding to the circular pattern observed on SLO. Within the circular plaque, the retina was predominantly of normal architecture. FA revealed variable hypofluorescence of both the rim and the center of the circular lesion throughout the early angiogram phases. In the late recirculation phase, small multifocal areas of hyperfluorescence were observed. OCT of geographic retinal dysplasia in the English springer spaniel revealed disorganization of both inner and outer retinal layers, and retinal detachment. Conclusions Circular plaques observed in the tapetal retina are predominantly formed by a thickening of inner retina, while retinal dysplasia has disorganization of both inner and outer retinal layers. Further etiologic research is needed, including pedigree mapping to determine whether retinal plaques are an acquired or inherited condition.

Retinal structural and microvascular abnormalities in retinal dysplasia imaged by OCT and OCT angiography

“…RD can also be the consequence of a non‐specific response to different insults to the developing eye, where some of the known causes include intrauterine viral infections with herpesvirus, 7 and ionizing radiation 8 . Geographic RD is recognized in many breeds of dogs among which include German shepherds, Labrador retrievers, Golden retrievers and their crosses and others with an unclear genetic basis and the condition is usually not a perinatal defect 2,5,9 …”

“…8 Geographic RD is recognized in many breeds of dogs among which include German shepherds, Labrador retrievers, Golden retrievers and their crosses and others with an unclear genetic basis and the condition is usually not a perinatal defect. 2,5,9 Geographic RD can be unilateral or bilateral and it is easily identified by indirect ophthalmoscopy as a dark hyporeflective circular plaque in most cases located around or close to the major dorsal venule. 5 These lesions have been studied by Optical Coherence Tomography (OCT) confirming that the plaque is a disorganized thickening of the inner retina, affecting the retinal nerve fiber, ganglion cell and inner plexiform layers (NFL, GCL, IPL), that can be bordered by retinal folds and rosettes.…”