Clinical and histological characteristics of canine ocular gliovascular syndrome.

OBJECTIVE: To characterize the clinical, diagnostic, and histopathologic findings in dogs with canine ocular gliovascular syndrome (COGS). PROCEDURES: The archives at the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were used to identify eyes with COGS. Histopathological inclusion criteria included: a neovascular membrane extending from the optic nerve head or retina, clusters of spindle cells lacking vascularization within the vitreous, and histological signs of glaucoma. Special and immunohistochemical (IHC) staining techniques were performed. Clinical data, treatments, and outcomes were obtained from case records and information provided by submitting veterinarians. RESULTS: Thirty-seven eyes of 36 dogs were identified with COGS. The average age at diagnosis was 8.8 years (±2.2). The relative risk for a Labrador retriever affected by COGS was significantly greater (9.3 times) (P < 0.0001) when compared to all other dog breeds within the COPLOW database. Most dogs presented with hyphema and secondary glaucoma; average intraocular pressure was 39 mmHg (±19). Average time to enucleation or evisceration was 27 days. Vitreal cells stained positive with IHC for glial fibrillary acidic protein in 14 of 17 globes, and vascular endothelial growth factor was expressed in the vitreal cells in five of five globes. CONCLUSIONS: We have defined a syndrome associated with vitreal glial cell aggregates and neovascular proliferation from the optic nerve or retina, which leads to neovascular glaucoma. The inflammation and secondary glaucoma resulting from this syndrome appear poorly responsive to conventional medical therapies. The exact etiology of COGS remains undetermined, but a systemic etiology is unlikely.

Intravitreal gas injection for the treatment of experimental vitreous hemorrhage in rabbits.

PURPOSE: To determine the effectiveness of intravitreous gas injection in the management and clearing of experimental vitreous hemorrhage. METHODS: A total of ten New Zealand white rabbits received an injection of 0.4 ml of autologous blood into the vitreous of the right eye. After 24 hours of the vitreous hemorrhage simulation, six eyes were randomly assigned for treatment with na intravitreous injection of 0.2 ml of 100% perfluoropropane gas (C3F8) (group A), while four eyes received a control injection of an equivalent volume of balanced salt solution (group B). The persistence of vitreous opacification, which was graded at pre-established time points during 32 days of follow-up, was evaluated on the basis of visibility of retinal details in each of the four quadrants. RESULTS: In the gas-treated group (A), a partial view of the retina in the four quadrants was possible at 15 days, while at 32 days, the vitreous cavity was completely free of blood in all eyes, allowing unobstructed observation of the fundus. No retinal details could be observed in the control group after 32 days of follow-up. CONCLUSIONS: Gas injection proved effective in the treatment of experimental vitreous hemorrhage. It was significantly better than the injection of balanced salt solution, according to criteria of extension, intensity, and clearing time. Its technical facility, lack of complications, and low cost encourage additional research into gas injection to add knowledge to this initial study and to clarify its potential usefulness to treat persistent vitreous hemorrhage as well as to elucidate some unique pathophysiology features of blood catabolism in the vitreous.

Ultrasonographic abnormalities in the eyes of dogs with cataracts: 147 cases (1986-1992).

Records of 147 dogs with cataracts and that had an ultrasonographic examination of their eyes were reviewed. Ultrasonography was performed, using a real-time mechanical sector scanner (7.5 or 10.0 MHz transducer), after topical anesthesia of the cornea. Vitreous degeneration was diagnosed in 23% of the eyes examined. Retinal detachment was detected in 11% of all eyes, but was detected in 4% of eyes with immature cataracts, 6.5% of eyes with mature cataracts, and 19% of eyes with hypermature cataracts. In 66% of the eyes, the cataract was the only ultrasonographic abnormality found. Vitreous degeneration and retinal detachment were most often observed in eyes with a hypermature cataract, and were uncommon in eyes with an immature cataract. We concluded that ultrasonographic examination can detect abnormalities of the posterior segment when opacity of the anterior segment precludes complete ophthalmoscopic examination and that it is a quick and easy procedure for screening dogs for retinal detachment prior to cataract surgery.

A morphologic study of intravitreal membranes associated with intraocular hemorrhage in the dog.

Abstract We aimed to characterize intravitreal membranes in dogs and determine, if possible, associated predisposing conditions. Five globes in which intravitreal membranes were identified were evaluated. These originated from four Labrador Retrievers or Labrador-cross dogs and a Springer Spaniel. The ages of the dogs ranged from 4 to 11 years. Standard histology and immunohistochemical procedures for factor VIII-related antigen, smooth muscle actin (SMA), vimentin and glial fibrillary acidic protein (GFAP) were performed. Intravitreal membranes varied from loosely to highly organized. The extent of organization corresponded with increasing immunoreactivity for vimentin and GFAP, indicating their predominantly glial origin. They were never immunopositive for smooth muscle actin, nor were they vascularized. In all cases, they were associated with intravitreal hemorrhage. Additional common findings included epiretinal membranes, retinal neovascularization, preiridal fibrovascular membranes and glaucoma. Intravitreal membranes may be a sequelae of intravitreal hemorrhage. This in turn, may arise from new vessels associated with epiretinal or preiridial membranes, or hemorrhage associated with optic disc cupping or retinal neovascularization. All of these phenomena may accompany glaucoma.