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

OBJECTIVE: To describe the in vivo structural characteristics of multifocal and geographic retinal dysplasia visualized with advanced retinal imaging including confocal scanning laser ophthalmoscopy (cSLO), optical coherence tomography (OCT), en face OCT, and the novel vascular imaging technique OCT angiography (OCTA). DOGS STUDIED AND PROCEDURES: Two dogs were diagnosed with unilateral multifocal or geographic retinal dysplasia and underwent advanced retinal imaging under general anesthesia at the Retinal Disease Studies Facility of the University of Pennsylvania. RESULTS: In both cases, the morphological pattern of the lesions was similar including outer retinal folds that invaginated and formed tubular retinal rosettes, surrounding a central inner retinal thickening (multifocal) or plaque (geographic). The two dogs had multiple vascular anomalies in the lesions such as increased tortuosity, abnormal change of vessel diameter including aneurysms and capillary network disruption. We also identified increased autofluorescence by AF cSLO with short wavelength light source (488 nm and barrier filter at 500 nm), and several areas of photoreceptor loss associated with the lesions. CONCLUSION: The use of OCTA allowed the identification of microvascular abnormalities associated with multifocal and geographic retinal dysplasia in two dogs. To our knowledge, this is the first report where the dye-free OCTA technique is used to study vascular lesions in canine retinas.

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

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.

Unilateral sporadic retinal dysplasia: results of histopathologic, immunohistochemical, chromosomal, genetic, and VEGF-A analyses.

PURPOSE: To describe new findings in a case of unilateral retinal dysplasia. METHODS: Histopathologic evaluation of an enucleated globe and analysis with immunohistochemical probes, karyotyping, and genetic analysis for the Norrie gene, and aqueous assay for vascular endothelial growth factor A (VEGF-A). RESULTS: Histopathological examination of the globe revealed retinal dysplasia with pseudorosette formation, abnormal or absent retinal nuclear lamination, a paucity of disorganized retinal microvasculature, retinal infoldings, advanced gliosis, persistent hyperplastic vitreous, exuberant neovascularization of the vitreous, and iris neovascularization (identical to the findings observed in bilateral Norrie disease). Immunohistochemistry disclosed GFAP-positive and GLUT-1-positive gliosis and retinal and persistent hyperplastic vitreous microvessels that were CD34-positive and GLUT-1-negative. Ki-67-positive retinal cells were polarized toward the subretinal space and absent in the retinal invaginations and pseudorosettes. A normal karyotype was found, and DNA sequencing revealed no known mutation in the region of the Norrie gene (NDP) in sputum or retinal DNA. Aqueous obtained immediately after enucleation contained an exceptionally high concentration of VEGF-A (4.5 ng/mL). CONCLUSIONS: Despite the failure to find an abnormal NDP allele, other unexplored NDP regions, an undetected defect restricted to retinal tissues, or an autosomal mutation coupled with disrupted signaling pathways may be responsible for the condition. High aqueous VEGF-A suggests that this cytokine may play a role in pathogenesis in conjunction with other pathways.

Chorioretinal dysplasia, hydranencephaly, and intracranial calcifications: pseudo-TORCH or a new syndrome?

PURPOSE: To report the association of severe chorioretinal dysplasia, hydranencephaly, microcephaly, and intracranial calcification in children with no evidence of intrauterine infections. METHODS: Two unrelated female infants with visually inattentive behaviour, hydranencephaly, and intracranial calcification were referred for an ophthalmological opinion. RESULTS: The fundus examination and computerised tomograms (CT scans) of head were similar in both children. There was bilateral extensive chorioretinal dysplasia, intracranial calcifications, and hydranencephaly. Serology was negative for acquired intrauterine congenital infections. CONCLUSIONS: We report two cases that may represent a new syndrome or the more severe end of the spectrum of the pseudo-TORCH (toxoplasma, rubella, cytomegalovirus, and herpes simplex) syndrome. The association of chorioretinal dysplasia with the pseudo-TORCH syndrome has not been reported previously.