Clinical and histological characteristics of canine ocular gliovascular syndrome.

PubMed ID: 25174277

Author(s): Treadwell A, Naranjo C, Blocker T, Zarfoss M, Dubielzig RR. Clinical and histological characteristics of canine ocular gliovascular syndrome. Vet Ophthalmol. 2015 Sep;18(5):371-80. doi: 10.1111/vop.12209. Epub 2014 Sep 1. PMID 25174277

Journal: Veterinary Ophthalmology, Volume 18, Issue 5, Sep 2015

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.