Records of 50 dogs with signs of retrobulbar disease that had ultrasonography and diagnosis based on results of cytopathology or histopathology were reviewed retrospectively. Abnormalities were identified ultrasonographically in 43 (86%) dogs. Mass effect was identified in 42% of dogs with neoplasia and 30% of dogs with abscess. Ten of 11 (91%) orbital bone lesions were in dogs with retrobulbar neoplasia. A cavitary lesion was recognized ultrasonographically in 75% of dogs with salivary mucocele and 50% of dogs with retrobulbar abscess. Neoplasms occurred predominantly on the ventral or medial aspect of the orbit, or both, which reflects invasion by nasal or sinus neoplasms. Presence of orbital bone lesions or a mass on the medial aspect of the orbit suggests neoplasia; however, other ultrasonographic signs were nonspecific.

Cats with glaucoma typically present late in the course of disease. It is likely that glaucoma in cats is under-diagnosed due to its insidious onset and gradual progression, as well as limitations of some commonly used tonometers in this species. Treatment of glaucoma in feline patients presents a clinical challenge, particularly as glaucoma is often secondary to other disease processes in cats. In this review, we consider the clinical features, patho-physiology and classification of the feline glaucomas and provide current evidence to direct selection of appropriate treatment strategies for feline glaucoma patients.

Objective To validate intraocular pressure (IOP) readings obtained in cats with the TonoVet® tonometer. Animal Studied IOP readings obtained with the TonoVet® were compared to IOP readings determined by manometry and by the Tono-Pen XL in 1 normal cat and 2 glaucomatous cats. TonoVet® and Tono-Pen XL readings were also compared in a further 6 normal and 9 glaucomatous cats. Procedures The anterior chambers of both eyes of 3 anesthetized cats were cannulated and IOP was varied manometrically, first increasing from 5 to 70 mm Hg in 5 mm Hg increments, then decreasing from 70 to 10 mm Hg in 10 mm Hg decrements. At each point, two observers obtained three readings each from both eyes, with both the TonoVet® and Tono-Pen XL . IOP was measured weekly for 8 weeks with both tonometers in 6 normal and 9 glaucomatous unsedated cats. Data were analyzed by linear regression. Comparisons between tonometers and observers were made by paired student t-test. Results The TonoVet® was significantly more accurate than the Tono-Pen XL (p=0.001), correlating much more strongly with manometric IOP. In the clinical setting, the Tono-Pen XL , underestimated IOP when compared with the TonoVet®. Conclusions Both the TonoVet® and Tono-Pen XL provide reproducible IOP measurements in cats, however the TonoVet® provides readings much closer to the true IOP than the Tono-Pen XL . The TonoVet® is superior in accuracy to the Tono-Pen XL for detection of ocular hypertension and/or glaucoma in cats in a clinical setting.

Orbital infection with Aspergillus fumigatus was diagnosed in a Persian cat that was presented with chronic third eyelid protrusion and exophthalmos. Evidence of nasal, sinus, or disseminated aspergillosis was not detected in this cat. Complete surgical excision of diseased tissues was not possible during orbital exenteration, and infection subsequently extended into the tissues of the oral cavity. Oral therapy with itraconazole and parenteral therapy with amphotericin B were ineffective in resolving the infection. Oral therapy with a novel triazole, posaconazole, was curative.

Conjunctival swabs were taken from both eyes of 70 healthy domestic rabbits and cultured to determine the microbial population. Bacteria were recovered from 83 per cent of the specimens. DNase-negative Staphylococcus species (57 per cent) were the most commonly recovered organisms followed by Micrococcus species (25 per cent) and Bacillus species (19 per cent). Other organisms isolated included Stomatococcus species (8 per cent), Neisseria species (8 per cent), Pasteurella species (6 per cent), Corynebacterium species (6 per cent), Streptococcus species (6 per cent) and Moraxella species (4 per cent), and other bacteria were isolated less frequently. Statistical analysis showed that there appeared to be no significant difference between the bacterial isolation rates from different breeds of rabbit. Significantly more of the swabs taken from young rabbits yielded cultivable bacteria than did those taken from rabbits over 12 months of age.

This study was undertaken to describe the histopathologic abnormalities observed in canine eyes enucleated or eviscerated due to complications following phacoemulsification; to correlate these findings with the clinical abnormalities reported, and to suggest, if apparent, likely causes and effects of these abnormalities. Sixty-six canine globes or evisceration samples received for histopathologic interpretation over a 10-year period (1990-2000) were studied. All globes and evisceration samples were obtained from clinical patients examined by board-certified ophthalmologists. Hematoxylin and eosin (H&E) and alcian blue/periodic acid Schiff (PAS) stained sections were examined by light microscopy in every case. A tissue Gram stain was used when indicated. Clinical information obtained from the pathology submission form was reviewed in all cases, and obtained from questionnaires completed and returned by an ophthalmologist for 51 cases (77%). The most frequent histopathologic diagnoses were glaucoma (76%) and retinal detachment (64%). The most frequently reported clinical abnormalities in this series were glaucoma (86%) and uveitis (82%). Five problem areas were identified that appear to make a significant contribution to the failure of canine cataract surgery and merit further investigation: pre-iridal fibrovascular membranes; lens fiber regrowth; lens epithelial membranes; endophthalmitis, and the health of the corneal surgical incision.

The glaucomas are a group of diseases characterized by optic nerve damage that together represent a leading cause of blindness in the human population and in domestic animals. Here we report a mutation in LTBP2 that causes primary congenital glaucoma (PCG) in domestic cats. We identified a spontaneous form of PCG in cats and established a breeding colony segregating for PCG consistent with fully penetrant, autosomal recessive inheritance of the trait. Elevated intraocular pressure, globe enlargement and elongated ciliary processes were consistently observed in all affected cats by 8 weeks of age. Varying degrees of optic nerve damage resulted by 6 months of age. Although subtle lens zonular instability was a common feature in this cohort, pronounced ectopia lentis was identified in less than 10% of cats examined. Thus, glaucoma in this pedigree is attributed to histologically confirmed arrest in the early post-natal development of the aqueous humor outflow pathways in the anterior segment of the eyes of affected animals. Using a candidate gene approach, significant linkage was established on cat chromosome B3 (LOD 18.38, θ = 0.00) using tightly linked short tandem repeat (STR) loci to the candidate gene, LTBP2. A 4 base-pair insertion was identified in exon 8 of LTBP2 in affected individuals that generates a frame shift that completely alters the downstream open reading frame and eliminates functional domains. Thus, we describe the first spontaneous and highly penetrant non-rodent model of PCG identifying a valuable animal model for primary glaucoma that closely resembles the human disease, providing valuable insights into mechanisms underlying the disease and a valuable animal model for testing therapies.

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