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Granulomatous lens-induced uveitis was diagnosed in a mature male barred owl. Initial ocular examination revealed a large white mass in the left eye. Differential diagnoses for the mass included intraocular granuloma, neoplasia, foreign body, bacterial or fungal enophthalmitis, and fibrotic hematoma. After enucleation of the left globe, histologic examination revealed the mass to be a granulomatous inflammatory reaction to a posteriorly luxated, traumatized lens. Lens-induced uveitis should be considered whenever a bird has suffered lenticular trauma.

Feline sarcoma virus (FeSV) is a naturally occurring virus that causes spontaneous tumors in cats. The immunologic and morphologic characteristics of these tumors have been studied extensively. It was recently observed in experiments undertaken to induce systemic malignancy with this virus, that severe uveitis and clinical blindness occurred. An investigation of the ophthalmologic changes was undertaken. A fulminent anterior uveitis was produced in cats by a series of subcutaneous injections of live FeLV-FeSV. This intraocular inflammation occurred in five of six animals using high viral titers, and four of seven with lower titers, resulting from the freeze thaw process. On histopathologic examination, most animals demonstrated dysplastic changes of the ciliary body in addition to the iridocyclitis. The remainder of the eye was unaffected. These animals developed systemic tumors unaccompanied by local inflammation, many of which spontaneously regressed. Notable features of this potential model for uveitis are that (1) direct injection into the eye is unnecessary, and (2) intravenous administration inducing immune tolerance with antigenic overload presented to the spleen is avoided. This inflammatory reaction seems to be specific to the iris and ciliary body. Levels of live virus detected in the aqueous humor exceeded those in the serum. These results suggest that the virus may be actively secreted by the ciliary epithelium, or may preferentially proliferate within the eye.

Diffuse clouding of the cornea ('corneal oedema', 'blue eye') of sudden onset and usually transient duration and with accompanying anterior uveitis, may be attributable to natural infection with canine adenovirus type 1 (CA-1) or to vaccination with live modified virus. It is now recognised that kerato-uveitis is a manifestation of type III hypersensitivity in which immune complex formation resulting from the release of virus, especially from infected corneal endothelial cells, brings about corneal endothelial damage and hence corneal oedema. A proportion of cases fail to resolve. At least one breed, the Afghan hound, appears to be particularly susceptible. The incidence of ocular lesions resulting from vaccination has stimulated the development of new vaccines incorporating canine adenovirus type 2 (CAV-2), a serotype which has been shown not be cause endogenous ocular disease.

Canine adenovirus-type 1 (CAV-1)-antibody complexes caused severe anterior uveitis with corneal edema ("blue eye") when injected into the anterior chamber of normal dogs. The response of the anterior uvea to such immune complexes (IC) was similar to the spontaneously occurring disease. In the presence of complement (C'), IC caused release of neutrophile chemotactic factors. Following phagocytosis of IC-C' leukocytes released lysosomal enzymes, as indicated by the presence of acid phosphatase in the surrounding medium. Membrane bound viral aggregates, presumably IC, were common in neutrophiles and in macrophages that had infiltrated the anterior chamber of opaque eyes that occurred after intravenous (IV) inoculation with attenuated CAV-1. These data were incorporated into a postulated scheme for the pathogenesis of CAV-1 uveitis with corneal edema.

After the observation of 2 horses with uveitis on a horse farm in the Minnesota River valley, 100 horses from this geographic area were given ophthalmologic examinations and were evaluated serologically for leptospirosis. A statistically significant (P less than 0.001) association was observed between the finding of antibodies against Leptospira interrogans serovar pomona and uveitis.

Uveitis was induced in dogs by intracameral injection of canine lens protein. The lipoxygenase inhibitors phenidone and norhydroguaiaretic acid, and dimethyl sulfoxide decreased fibrin production at 0.5 and 1 hour after induction of uveitis. Phenidone and norhydroguaiaretic acid also inhibited the initial increase in intraocular pressure early in the course of inflammation. Leukotriene B4 in the aqueous was measured by use of radioimmunoassay at 1 hour after inflammation. In control dogs, 230 to 1,700 pg of leukotriene B4/ml was measured; in dogs treated with phenidone, leukotriene B4 was not measured.

The effects of a mesogenic strain of Newcastle disease virus on ocular and paraocular structures were studied in 10-to-12-week-old chickens inoculated conjunctivally, intraocularly, intracerebrally, or intravenously. Paraffin-embedded tissues were examined by light and fluorescent microscopy using conventional staining and immunohistochemistry. Lesions were most severe in intraocularly inoculated chickens, where a marked iridocyclochoroiditis was evident from 8-12 hours up to 21 days postinfection. Viral antigens were detected in the iris, ciliary body, Schlemm's canal, and occasionally the lens, choroid, and base of the pecten. Although optic neuritis and iridocyclochoroiditis were found in intracerebrally inoculated birds, no viral antigens were detected in the optic nerve.

Glaucoma is a disease complex in which one of several exciting factors is responsible for an elevation of the intraocular pressure beyond its normal physiological limitations. At present two types of primary glaucoma may be described for the dog, while the recognition of secondary glaucoma as a complication to lens luxation, uveitis, trauma, infection and neoplasia has long been established. Identification of the causal factor within this complex plays a necessary part in the institution of successful treatment.

Uveitis, characterized by infiltrates of lymphocytes and plasma cells, was the principal ocular lesion in 122 sapphire and pastel mink affected with experimental Aleutian disease. It was present to various degrees in all but five mink examined five to 164 weeks after inoculation (intraperitoneal or intranasal) with any of four North American strains of Aleutian disease virus. The uveitis, mostly iridocyclitis, was accompanied often by protein-rich fluid in the anterior chamber and less often by fibrin and cells in the vitreous body. Cellular infiltration of the limbus, seldom pronounced, also occurred in about 20% of the mink. In 11 mink with moderate or severe uveitis, the retina was detached by pools of protein-rich fluid. Infiltrates of lymphocytes, plasma cells, and a few histiocytes often were found in the orbital soft tissues, occasionally in association with retrobulbar arteritis. In general, the ocular lesions were more severe in sapphire than in pastel mink. The uveitis accompanies glomerulonephritis, the principal lesion of Aleutian disease, much more regularly than do several other lesions of the disease. Like the glomerulonephritis, it probably results from the deposition of circulating immune complexes.

Rupture of the lens capsule in 20 dogs resulted in zonal, perilenticular inflammation that did not respond to symptomatic therapy and resulted in the loss of the globe. The reaction was dominated by lens epithelial proliferation, pupillary occlusion, and glaucoma in 11 of the 20. This reaction, herein named phacoclastic uveitis, is unique and easily distinguished from the mild lymphocytic-plasmacytic anterior uveitis that accompanies leakage of lens material through an intact capsule of a hypermature cataract (phacolytic uveitis). None of the dog eyes had the granulomatous perilenticular inflammation that is the hallmark of lens-induced (phacoanaphylactic) uveitis in humans.

The relationship between breed and the risk of developing sarcoid tumours or uveitis of unknown etiology was evaluated in a retrospective study of 16242 equine cases admitted between 1975 and 1987 to the New York State College of Veterinary Medicine Large Animal Hospital, and 3198 equine tissue samples sent to the New York State Veterinary Diagnostic Laboratory between 1977 and 1987. Of 120 sarcoid cases from the Large Animal Hospital, sarcoids were twice as likely to develop in Quarter Horses (odds ratio, OR = 1.8, P less than 0.05) relative to Thoroughbreds and less than half as likely to develop in Standardbreds (OR = 0.2, P less than 0.001) relative to Thoroughbreds. Similarly, of 376 sarcoid cases from the Diagnostic Laboratory, Quarter Horses had a significantly higher risk of developing sarcoid (OR = 2.0, P less than 0.001) relative to Thoroughbreds, while Standardbreds had a significantly lower risk of developing sarcoid (OR = 0.5, P less than 0.05) relative to Thoroughbreds. In the uveitis diagnosis category, Appaloosas had a significantly higher risk of developing uveitis (OR = 6.4, P less than 0.001) relative to Thoroughbreds, while Standardbreds had a significantly lower risk of developing uveitis (OR = 0.4, P less than 0.05) relative to Thoroughbreds.

The rare occurrence of lens-induced uveitis in a cat is described and compared with the similar entity in humans. The characteristic histopathological features are presented and compared in the two species.

A radioimmunoassay was developed for detection of immunoglobulin in the aqueous of normal horses and horses with intraocular diseases. Levels of albumin were detected by radial immunodiffusion. Results of assays on samples from normal eyes from which aqueous was obtained by paracentesis under anesthesia were 32.10 +/- 21.50 microgram/ml for IgG, 0.05 +/- 0.01 microgram/ml for IgM, 0.04 +/- 0.02 microgram/ml for IgA and 34.0 +/- 38.0 microgram/ml for albumin. Results in 138 normal eyes sampled post mortem were 41.56 +/- 38.65 microgram/ml for IgG, 0.18 +/- 0.43 microgram/ml for IgM, 0.46 +/- 1.45 microgram/ml for IgE and 184 +/- 240 microgram/ml for albumin. Levels in abnormal eyes were some 50-120% greater, and very high levels were noted in cases of clinically documented uveitis. The aqueous to serum ratio of the proteins measured generally varied in relation to the molecular weights and was increased in diseased eyes. The ratio of IgG/albumin in the diseased eyes was less which suggested leakage of protein from an impaired blood/aqueous barrier rather than intraocular antibody synthesis.

Dogs inoculated intravenously with attenuated canine adenovirus type 1 developed anterior segment inflammation and corneal edema. During the stage of mild anterior uveitis, virus was isolated from the aquious fluid, and by electron microscopy, viral replication was found to occur in corneal endothelial cells. Later, at the stage of severe anterior uveitis with corneal edema, virus was not isolated from the aqueous fluid and cells containing intranuclear (replicating) virus were not found. At this stage, many inflammatory cells had infiltrated the anterior chamber and contained numerous membrane-bound viral aggregates (viral-antibody complexes). Phagocytized viral-antibody complexes were present in the areas of most prominent endothelial cell destruction. Peripheral to the principal lesion sites, inflammatory cells had dissected the endothelium from Descemet membrane. After recovery from the disease, an intact endothelial cell layer was present.

Bilateral anterior uveitis, nonregenerative anemia, and thrombocytopenia were found in a 9-month-old Chow Chow infected with Ehrlichia platys. Diagnosis was based on the finding of basophilic inclusions in platelets and an E platys antibody titer. The dog was treated orally with tetracycline, topically with antibiotic/corticosteroid, and topically with a mydriatic.

The continued study of immunology and its relationship to diseases of the eye will hopefully give some insight into the pathogenic mechanisms of certain ocular diseases of many species, including the horse. It may lead to a better understanding of equine recurrent uveitis, a disease that has remained an enigma for years and that now appears to be an immunologic hypersensitivity response to a number of varied antigens. The precise mechanism of the inflammation is still unclear, and the immunologic response may be variable or mixed depending upon the inciting antigen. Other ophthalmic diseases in the horse, such as conjunctivitis, chorioretinitis, and less well-defined entities such as superficial punctate keratitis, may also have an immunologic component in their pathogenesis. An appreciation of immunopathologic mechanisms may thus enhance the veterinarian's understanding of the pathophysiology and treatment of equine ocular disease.

Idiopathic panuveitis with retinal detachment was associated with facial poliosis, vitiligo, and alopecia in 6 dogs; 4 were adult males. Dermatohistologic examination of affected facial sites from all dogs revealed a lichenoid dermatitis and unusual histiocytic cells. Intensive topical and systemic corticosteroid and topical mydriatic/cycloplegic therapy was successful in controlling uveitis in all dogs for variable periods. Three dogs, monitored for 12, 30, and 46 months, retained useful vision despite infrequent recurrence of uveitis. One dog was lost for subsequent examination. Two dogs were euthanatized and necropsied. Ocular histologic examination of these dogs revealed extensive granulomatous iridocyclitis and choroiditis, with retinal detachment and lenticular degeneration.

The aqueous humor of 20 cats and 17 dogs was examined to determine its importance as a diagnostic aid in anterior uveitis. Aqueous humor cytology and protein concentration differed in acute and chronic anterior uveitis but was not specific enough to be an aid in the diagnosis of feline infectious peritonitis. Cytologic examination of the aqueous humor was of benefit in determining the cause of anterior uveitis in 2 of 7 cases of lymphosarcoma. Cultures of aqueous humor proved negative in uveitis of more than 3 weeks' duration. Pseudomonas sp was cultured from the aqueous humor of a dog with anterior uveitis secondary to a perforating corneal injury.

Clinical toxoplasmosis was diagnosed in 15 cats by correlating serologic evidence of infection and clinical signs to either response to therapy or histopathologic demonstration of the organism. Ophthalmic manifestations, primarily involving the anterior segment, were common. Other common physical examination abnormalities included muscle hyperesthesia, fever, and weight loss. Response to therapy was variable, but administration of clindamycin hydrochloride resulted in resolution of all clinical signs not involving the eyes in surviving animals. This drug, alone or in combination with corticosteroids, led to total resolution of clinical signs in four of four cats with active retinochoroiditis and in six of nine cats with anterior uveitis. Four of the 15 cats had concurrent infection with feline immunodeficiency virus (FIV). Feline leukemia virus antigen or antibodies to feline infectious peritonitis virus were not detected.

Experimental allergic unveitis (EAU) was produced in strain 13 guinea pigs after immunization with purified guinea pig retinal rod outer segments and pigment epithelium (PE) in mycobacterial adjuvant emulsion. The lesions of EAU appear as inflammatory infiltrates of the iris, ciliary body, and choroid, often with photorecptor degeneration. Specific antibodies are frequently detected in the serum of some but not of all animals with clinical uveitis. Immunohistochemical staining of normal and inflamed eyes with serum from the immunized animals with clinical disease demonstrated specific antigens localized in the retinal photoreceptor layers, whether or not circulating precipitating antibodies were also present in the serum. All immunized animals demonstrated delayed-type hypersensitivity (DTH) characterized by skin reactions of mononuclear cells and by the vitro inhibition of migration of cells from the sensitized animals in the presence of specific antigen whether or not clinical uveitis occurred. However, stronger DTH reactions were observed during clinical uveitis. Cellular immunity appears to correlate with clinical EAU, whereas, no correlation was found with serum antibody. These findings suggest that the retinal photoreceptor cell and PE are the source of the significant antigens in autoimmune uveitis and retinitis.

Twenty-one dogs with ocular disease and blastomycosis were studied clinically. The most common ocular lesion was uveitis. Other findings included retinal separation, panophthalmitis, and glaucoma. The results of the study indicated that when uveitis is found in dogs in central United States, east of the Mississippi River, blastomycosis should be a diagnostic consideration. When the uveitis was associated with lung, lymph node, skin, bone, or testicular lesions, the likelihood of blastomycosis was greater.

An enzyme linked immunosorbent assay was developed for the detection of immunoglobulin class specific antibodies to Leptospira interrogans serovar pomona in the serum and aqueous humor of horses. Serum antibody was also assayed by microscopic agglutination tests. Although higher levels of antibody were found in sera from horses with signs of uveitis, the association was not statistically significant. Antibodies to pomona were detected in the aqueous of 12 eyes from the 101 horses sampled at a slaughterhouse, and in most instances, a comparison of the aqueous/serum antibody level with that of the total aqueous/serum IgG level indicated intraocular antibody synthesis. Antibodies were also found in 4 aqueous (or vitreous) samples out of 9 obtained from horses with clinically documented uveitis and the above comparison again indicated intraocular antibody synthesis. The data point to an important role for pomona as an etiology of equine recurrent uveitis but also emphasize that the initiating cause for this disease is often obscure in that association with leptospirosis cannot be shown in many instances.

Two cases of H.c.c. which occurred in winter 1987 in Vienna are described. Case one was a female Chow-Chow, 8 weeks of age, that died from the peracute form of the disease. The diagnosis was confirmed by histology and direct immunofluorescence. Case two, a 9-month old female Kuvacz, showed clinical signs of the subacute form of H.c.c. She was hospitalized and therapy was successful. The disease was diagnosed by the typical clinical signs and the raise of antibodies in paired serum samples. Etiology, clinical signs and immunology of H.c.c. are discussed.

The experimental model of immunogenic uveitis induced by intraocular injection of human serum albumin in rabbits was inhibited by the topical application of cyclosporin A. The acute nonspecific inflammatory response that immediately follows intravitreous injection was not affected. However, the severe panuveitis that develops during the second week was markedly reduced. The safety and efficacy of topically applied cyclosporin A in this model of uveitis suggests that topical administration of this antigen-nonspecific immunosuppressor may be an effective route of therapy for certain immune-mediated forms of uveitis.