Cartilaginous metaplasia in the sclera of Suffolk sheep.

Scleral cartilaginous metaplasia was detected by routine histologic examination of globes from 5 Suffolk sheep from a scrapie pathogenesis study. The extent of the metaplasia varied among the sheep but was always posterior to the tapetal fundus. The matrix surrounding chondrocytes stained intensely with alcian blue and was immunopositive for type II collagen. Retrospective evaluation of additional eyes from Suffolk and Cheviot sheep used in various scrapie pathogenesis studies at the authors' facility revealed similar histologic changes in 40% and 12.7% of eyes examined, respectively. The clinical significance of this previously unreported finding is unknown.

Multiple limbal haemangiosarcomas in a border collie dog: management by lamellar keratectomy/sclerectomy and strontium-90 beta plesiotherapy.

An eight-year-old, neutered, male border collie dog was presented with a six-week history of left ocular discomfort and a raised, red mass at the lateral limbus. The right eye had been enucleated approximately 12 months previously following suspected trauma when the eye had become red and painful. The mass was excised using superficial keratectomy/sclerectomy and the surgery site was treated with strontium-90 beta radiation. Histopathological findings were consistent with a diagnosis of haemangiosarcoma. Immunohistochemical staining showed uniform expression of CD31 in neoplastic cells, confirming their endothelial origin. Two further treatments with strontium-90 beta radiation were applied to the surgical site at weekly intervals. Twenty-six weeks after surgery, a second, raised, red limbal mass became apparent at the medial limbus of the left eye. Surgical excision and adjuvant strontium-90 beta plesiotherapy were performed as described for the initial tumour. Routine histopathological analysis confirmed haemangiosarcoma at this site. Eighty-six weeks following the initial presentation, no recurrence of ocular haemangiosarcoma was evident.

Ocular lesions in Watanabe heritable hyperlipidemic rabbits.

Hyperlipidemic ocular lesions are described for Watanabe heritable hyperlipidemic (WHHL) rabbits. Male WHHL rabbits 8 months old exhibited serum hyperlipidemia and ophthalmoscopically yellowish-white lesions along the corneoscleral junction and in the iris. Histopathologically, foamy macrophages aggregated in the stroma of the cornea, iris, and ciliary body were observed. These findings have been interpreted as lipid keratopathy. In addition, multiple clusters of a large number of foamy macrophages occurred throughout the choroid and sclera in association with the blood vessels. The lesions in the choroid and sclera could not be detected ophthalmoscopy, yet were much more prominent than those in the cornea, iris, and ciliary body, suggesting greater involvement and earlier onset of lipidosis at these sites associated with hyperlipidemia in WHHL rabbits.

Staphyloma in a cat.

A unilateral scleral staphyloma in an 18-month-old, female spayed Domestic Short-haired cat was treated with excision, primary closure and fascial graft. Other ocular abnormalities noted on examination included iris coloboma, anterior cortical cataract, focal lens equator flattening and retinal dysplasia. The staphyloma was presumed to be congenital in origin.

Update on llama medicine. Ophthalmology.

Review of the limited literature on camelid eyes suggests they are anatomically similar to those of domestic livestock species, except they lack meibomian glands and have iridial folds (rather than corpora nigra). The microbial flora of the healthy camelid conjunctival sac also appears to be similar to those of domestic livestock and pets, except that no Mycoplasma have been isolated from camelids. Ocular diseases for which camelids are presented to veterinarians are numerous and varied. The most frequently presented conditions are ocular trauma and congenital abnormalities. Trauma to cornea, conjunctiva, eyelids, and sclera has been reported. Therapies for these injuries are the same as for other animals. Most congenital abnormalities are cataracts and optic nerve colobomas, but congenital eyelid defects, conjunctival cysts, and multiple ocular defects have been reported. Although these conditions are not demonstrably hereditary, breeding of animals with congenital ocular defects is strongly discouraged. Intraocular inflammatory diseases are seen commonly in camelids. Uveitis and chorioretinitis may cause permanent visual loss, usually with no indication of cause. Equine herpesvirus 1 has been isolated from camelids with severe ocular inflammation and is a known cause of chorioretinitis and neurologic abnormalities. Systemic aspergillosis causes severe chorioretinitis in alpacas. More research is needed to improve our understanding of ocular physiology and pathology in camelids. Genetic studies also are needed to establish hereditary patterns of ocular maldevelopment. Additional information from researchers and practitioners should improve our ability to recognize and treat ocular disease in camelids.

Squamous cell carcinoma of the corneoscleral limbus in a dog.

Squamous cell carcinoma is an uncommon tumor of the cornea in dogs. A 12-year-old Shih Tzu with a history of chronic keratoconjunctivitis sicca was diagnosed as having squamous cell carcinoma of the corneoscleral limbus. The lesion was treated by surgical resection and cryotherapy. One year after surgery, multiple tumors, apparently unrelated to the first tumor, appeared on the same cornea. Keratoconjunctivitis sicca may have predisposed the dog to corneal squamous cell carcinoma development.