The feline glaucomas: 82 cases (1995-1999).

OBJECTIVE: To describe signalment, ophthalmic abnormalities, and response to treatment in cats with glaucoma. DESIGN: Retrospective study. ANIMALS: Eighty-two cats with 93 glaucomatous eyes. CRITERIA FOR INCLUSION: Medical records of all cats with glaucoma presented to the ophthalmology services at two referral specialty hospitals between 1995 and 1999 were reviewed. Cats were included if intraocular pressure (IOP) > 25 mmHg, if buphthalmos was present, or if a shallow anterior chamber was present and IOP > or = 5 mm Hg higher than the contralateral normal eye. RESULTS: Mean +/- SD age was 9.2 +/- 4.4 years. Thirty-one cats were female; 51 were male. Breeds included 69 domestic and 13 pure-bred cats. One eye was affected in 71 cats; both eyes in 11 cats. The most common presenting complaints and ophthalmic abnormalities were cataract, corneal edema, mydriasis, buphthalmos, cloudy eye, and blindness. Mean intraocular pressure in the affected eye was 36.4 +/- 14.7 mmHg. The glaucomas were believed to be secondary in 81 eyes, primary in five eyes, and undetermined in seven eyes. The goal of medical therapy was to maintain IOP in a comfortable range we presumed to be < 30 mm Hg in blind eyes, and to maintain IOP below 25 mmHg to preserve vision in visual eyes. Intraocular pressure was maintained in a comfortable range or normal range in 58% of all eyes using medical therapy alone. Surgery was performed in nine eyes after medical management failed. Sixty-seven eyes were blind, 21 were visual, and five had decreased vision at initial presentation. With treatment, vision was retained in nine eyes, deteriorated in five eyes, and was lost in three eyes. CONCLUSIONS: The glaucomas were most frequently secondary in cats and resulted in blindness prior to presentation in the majority of eyes in our study. Medical management controlled IOP in more than half of the eyes, and maintained vision in almost half of visual eyes.

Enrofloxacin-associated retinal degeneration in cats.

OBJECTIVE: The objective of this study was to evaluate the possible relationship between the administration of parenteral and/or oral [corrected] enrofloxacin and the onset of acute retinal degeneration in cats. The animals studied included 17 cats that received systemic enrofloxacin and developed retinal degeneration soon thereafter. PROCEDURES: In this retrospective clinical study, cats that received parenteral and/or oral [corrected] enrofloxacin and developed acute blindness were identified. Parameters recorded included breed, age, sex, enrofloxacin dosage (daily dose and number of days administered), medical condition for which the antibiotic had been prescribed, ophthalmic signs, examination results, and the visual outcome. Fundus photographs were obtained in seven cats, and electroretinography was performed in five cats. Histopathology was performed on two eyes from one cat (case 1) that received enrofloxacin 5 months previously and developed retinal degeneration. RESULTS: All cats were the domestic shorthair breed; seven were females (one neutered) and ten were males (seven castrated). Ages ranged from 3 to 16 years old (mean +/- SD; 8.8 +/- 4.6 years). The medical disorders for which enrofloxacin was administered ranged from lymphoma and pancreatitis to otitis and dermatitis, and eight cats had urinary diseases. The daily and total dosage of enrofloxacin and number of days of administration were also highly variable. Presenting clinical signs were most often mydriasis and acute blindness. All cats had diffuse retinal degeneration as evidenced by increased tapetal reflectivity and retinal vascular attenuation. Absence of recordable electroretinographic responses suggested diffuse and extensive outer retinal disease. Vision returned in a few cats, but the retinal degeneration persisted or even progressed. Histopathology of two eyes revealed primarily outer retinal degeneration, with diffuse loss of the outer nuclear and photoreceptor layers, and hypertrophy and proliferation of the retinal pigment epithelium. CONCLUSION: Parenteral and/or oral [corrected] enrofloxacin is potentially retinotoxic in some cats, and may result in acute and diffuse retinal degeneration. Blindness often results, but some cats may regain vision. Practitioners should adhere closely to the manufacturer's current enrofloxacin dosage recommendation (5 mg/kg q 24 h), and continue clinical observations for this drug toxicity in cats.

A comparison of corneal sensitivity between brachycephalic and Domestic Short-haired cats.

OBJECTIVE: To compare sensitivity of the central and peripheral cornea of brachycephalic and Domestic Short-haired (DSH) cats. DESIGN: Prospective study. ANIMALS: Fifty DSH, thirteen Persian, and seven Himalayan cats. CRITERIA FOR INCLUSION: Healthy DSH, Persian, or Himalayan cats older than 6 months, with a normal ophthalmic examination and Sno-strip values greater than or equal to 5 mm wetting/60 s. MATERIALS AND METHODS: Corneal sensitivity was measured using a Cochet-Bonnet aesthesiometer. The cornea was touched using the tip of the monofilament, decreasing the fiber length in 5 mm increments until a blink reflex occurred. Corneal touch threshold was defined as the stimulus that elicited a corneal blink reflex greater than 50% of the time. RESULTS: Mean central and peripheral corneal touch threshold (CTT, +/- SD in gm/mm2) for the DSH cats were 1.79 +/- 2.33 and 5.01 +/- 5.07 in the right eye (OD), and 1.74 +/- 1.65 and 5.02 +/- 4.55 in the left eye (OS). Mean central and peripheral CTT +/- SD (gm/mm2) for the brachycephalic cats were 4.09 +/- 5.29 and 6.18 +/- 5.65 OD, and 3.18 +/- 3.75 and 7.66 +/- 6.24 OS. Statistical analysis of the data revealed a significantly higher CTT in the central (P = 0.019) and peripheral (P = 0.003) cornea of brachycephalic than DSH cats. When evaluated for gender, this difference persisted in female cats, but did not hold true for male cats. A significant difference in CTT was found between central and peripheral cornea within both groups of cats. CONCLUSIONS: The central cornea is less sensitive in brachycephalic than DSH cats. The central cornea is more sensitive than the peripheral cornea in both brachycephalic and DSH cats.

Management of intraocular inflammatory disease.

The uvea of the eye is divided into the anterior uvea (iris and ciliary body) and posterior uvea (choroid). Clinical signs of anterior uveitis include conjunctival hyperemia, corneal edema, aqueous flare, miosis, and a decrease in intraocular pressure. Inflammation of the posterior uvea often involves the retina as well resulting in a chorioretinitis. Clinical signs of chorioretinitis may include multifocal lesions in tapetal or nontapetal fundus, retinal detachment, and a decrease in vision. The etiology of uveitis is complex and includes numerous infectious, neoplastic, immune-mediated, and other diseases. Treatment is directed at the underlying systemic disease, if present, as well as symptomatic treatment for the eye. The diagnostic and therapeutic approach to a patient with uveitis is discussed.

Nonhealing corneal ulcers in cats: 29 cases (1991-1999).

OBJECTIVE: To compare mean healing times after debridement, debridement with grid keratotomy, and superficial keratectomy in cats with nonhealing corneal ulcers. DESIGN: Retrospective study. ANIMALS: 29 cats with 36 nonhealing corneal ulcers. PROCEDURE: Medical records of cats with nonhealing corneal ulcers were reviewed. Signalment, duration of clinical signs, ophthalmic abnormalities, and response to various treatment protocols were recorded. RESULTS: Mean age of affected cats was 7 years, 8 months. Affected breeds included domestic shorthair (17 cats), Persian (9), Himalayan (2), and Siamese (1). Clinical signs were evident for approximately 2 weeks prior to referral. Both eyes were affected in 4 cats. Mean healing time of ulcers treated with superficial debridement was 30 days. Mean healing time of ulcers treated with superficial debridement and grid keratotomy was 42 days. Superficial keratectomy was performed on 2 eyes and resulted in a healing time of 2 weeks. Formation of a corneal sequestrum was evident in 2 of 21 eyes treated with superficial debridement. Formation of a corneal sequestrum was evident in 4 of 13 eyes treated with superficial debridement and grid keratotomy. CONCLUSIONS AND CLINICAL RELEVANCE: Brachycephalic cats appear to be predisposed to developing nonhealing corneal ulcers. The combination of superficial debridement and grid keratotomy did not decrease mean healing time of nonhealing ulcers, compared with superficial debridement alone. Grid keratotomy may predispose cats with corneal ulcers to develop a corneal sequestrum.

Comparison of absorptive capacities of original and modified Schirmer tear test strips in dogs.

OBJECTIVE: To compare in vitro and in vivo absorptive capacities of modified Schirmer tear test strips with those of original strips, and to establish reference values for use with the modified strips. DESIGN: Prospective study. ANIMALS: 100 dogs. PROCEDURE: In vitro absorptive capacity was determined by immersing strips in an irrigating solution for 15 seconds and recording amount of wetting. In vivo absorptive capacity was determined by placing an original Schirmer tear test strip in 1 eye and a modified strip in the other eye of 50 dogs with normal or abnormal tear production. Time required to wet 10 mm of each strip was recorded. Measurements were repeated 30 minutes later after reversing which strip was placed in the left or right eye. Reference values (mean +/- SD) were determined by recording the time required to wet 10 mm of the modified strip in 50 healthy dogs. RESULTS: Amount of wetting was significantly less and time required to wet 10 mm was significantly greater for the modified strip, compared with the original strip. Reference values determined for the modified strip were 32 +/- 11 seconds in the right eye, 33 +/- 11 seconds in the left eye, and 32 +/- 10 seconds in both eyes. CONCLUSIONS AND CLINICAL RELEVANCE: Absorptive capacities of the original and modified Schirmer tear test strips were significantly different. Reference values determined for 1 strip should not be used for the other strip.

Prevalence of ocular abnormalities in cats with hyperthyroidism.

The purpose of this study was to investigate the occurrence of ocular abnormalities in hyperthyroid cats. One hundred hyperthyroid cats and 30 clinically normal, geriatric cats were studied. In both groups, ophthalmic examination was performed by use of slit-lamp biomicroscopy and indirect ophthalmoscopy after application of 1% tropicamide to dilate the pupil. Ocular abnormalities were common in both the hyperthyroid and euthyroid cats. Approximately 75% of all eyes were affected with 1 or more abnormalities, and the range of abnormalities involved all structures of the eye. Significant differences between the euthyroid and hyperthyroid cats were found in the prevalence of prominent suture lines, nonpigmented deposits on the posterior lens capsule, hyperreflective ring around the optic nerve, and hyperpigmentation of the area centralis, but all of these abnormalities were more common in the euthyroid cats than in the cats with hyperthyroidism. Active retinal lesions were only observed in 3 hyperthyroid cats (3%). The results of this study indicate that hyperthyroidism does not seem to be a frequent cause of abnormalities in the eyes of cats.

Retrobulbar pseudotumor of the orbit in a cat.

Idiopathic nonspecific inflammatory disease of the orbit (orbital pseudotumor) was diagnosed detected in a cat. The cat had progressive lagophthalmia, keratitis, and decreased motion of the right eye. Four months later, the left eye was affected in a similar manner. Response to antibiotics and immunosuppressive agents was not detected. Computed tomography of the brain and orbits revealed bilateral thickening of the sclera and episcleral tissues. Bilateral exenteration of the eyes was required because of worsening clinical signs or corneal perforation. Histologic examination revealed proliferation of spindle cells and fibrovascular tissue within and adjacent to the sclera.

Effect of single- and multiple-dose 0.5% timolol maleate on intraocular pressure and pupil size in female horses.

OBJECTIVE: To determine the effect of single and multiple-dose 0.5% timolol maleate on intraocular pressure (IOP) and pupil size between 8 AM and 8 PM. Animals Nine female horses with normotensive eyes. Procedure IOP, horizontal and vertical pupil size were measured on a single day, between 8 AM and 8 PM at hours 0, 0.5, 1, 2, 4, 6, 8, 10, and 12. A single dose of 0.5% timolol maleate was applied to both eyes immediately after the first measurement at 8 AM. IOP and pupil size were measured at 8 AM and 4 PM in a 5-day experiment of twice-daily application of 0.5% timolol maleate. RESULTS: A significant decrease in IOP from 24.9 +/- 4.2 mmHg prior to application of timolol maleate to 20.7 +/- 3.1 mmHg (4.2 mmHg = 17%) was observed 8 h after single-dose application. A significant decrease in horizontal pupil size (2.0 mm = 11%) was present 6 h after single-dose application. In the multiple-dose experiment, a significant decrease in IOP was present on days 4 and 5 as compared to IOP measured prior to application of timolol maleate. A significant decrease in horizontal and vertical pupil size was present throughout the 5-day study as compared to the values obtained prior to treatment. CONCLUSIONS: 0.5% timolol maleate significantly decreased IOP and pupil size in normo-tensive eyes of this group of female horses in both single and multiple twice daily applications.

Lens-induced uveitis.

has been described in humans and many animal species. Traumatic rupture of the lens capsule may result in vision-threatening intraocular inflammation that is poorly responsive to medical management. Phthisis bulbi, persistent uveitis or glaucoma often occurs in these eyes. Surgical removal of the lens material is generally indicated shortly after the injury in an effort to preserve vision. Leaking of lens proteins through an intact lens capsule may result in a lympho-plasmacytic anterior uveitis. This is most commonly associated with the presence of a hypermature cataract. The presence of lens-induced uveitis prior to cataract surgery significantly reduces the success rate of cataract surgery. Small amounts of circulating lens proteins maintain a normal T-cell tolerance for lens proteins. Lens-induced uveitis develops when a breakdown occurs of this normal T-cell tolerance. Immune complexes play an important role in the tissue damage associated with the ensuing inflammation. Other factors associated with the tissue damage include hydroxyl radicals, nitroxide radicals, and hydrogen peroxide and arachidonic acid metabolites. Treatment consists of topical and systemic anti-inflammatory medications, mydriatic agents, and glaucoma medications when indicated. Experimental pharmacological agents include dual cyclooxygenase/lipoxygenase inhibitors, interleukin-1 blockers, antioxidants and hydroxyl radical scavengers.

Feline retinal degeneration: clinical experience and new findings (1994-1997).

A retrospective case series of 26 cats with diffuse retinal degeneration is presented. The most common presenting complaints included bumping into objects, dilated pupils, and reluctance to jump. Ophthalmic examination findings were consistent with those reported in dogs with progressive retinal atrophy. Breed predilection of the Siamese cat was observed. Cats with primary retinal degeneration presented late in the clinical course of their disease, when vision loss was severe. Early symptoms such as night blindness and secondary ocular complications (i.e., cataract and retinal detachment), reported in dogs with progressive retinal degeneration, were not observed in this study. All cats showed excellent adaptive capabilities to blindness.

Multiple eyelid cysts resembling apocrine hidrocystomas in three Persian cats and one Himalayan cat.

Multiple eyelid cysts were evaluated and treated in four cats. Surgical removal of the cysts was performed in two cats. Histopathologic examination revealed multilocular cystic structures of various size. The cysts were lined by cuboidal to columnar cells with papillary or cystic projections into the cyst lumen. Periodic acid-Schiff-positive, diastase-resistant granules were seen within the apical cytoplasm of many of the cells. The eyelid masses in these cats resembled apocrine hidrocystomas in human beings, both clinically and on histopathologic examination.

Normal variation in, and effect of 2% pilocarpine on, intraocular pressure and pupil size in female horses.

OBJECTIVE: To determine normal variation in, and effect of 2% pilocarpine hydrochloride on, intraocular pressure (IOP) and pupil size in female horses during a specified period. ANIMALS: 10 female horses with normotensive eyes. PROCEDURE: IOP and horizontal and vertical pupil size were measured on a single day between 8 AM and 8 PM at hours 0, 0.5, 1, 2, 4, 6, 8, 10, and 12. Measurements were repeated after single- dose application of 2% pilocarpine to both eyes. IOP and pupil size were measured at 8 AM and noon in a 5-day experiment of twice-daily application of 2% pilocarpine. RESULTS: Variation in IOP and pupil size was not significant between 8 AM and 8 PM. Change in IOP or pupil size after a single dose of 2% pilocarpine also was not significant. In the multiple-dose experiment, the IOP at noon on the fifth day was significantly higher than the IOP in the morning on the first and second days. The IOP in the morning on the fifth day was significantly higher than the IOP in the morning and at noon on the first and second days. The IOP at noon on the fourth day was significantly higher than the morning IOP on the first and second days and at noon on the first day. The decrease in vertical pupil size was significant. CONCLUSIONS: Between 8 AM and 8 PM, variation in IOP and pupil size in normotensive eyes of horses is not significant. Two percent pilocarpine does not significantly change IOP between 8 AM and 8 PM in clinically normal horses after a single dose or multiple twice-daily applications. After multiple twice-daily applications, a trend toward an increase in IOP was seen, and the decrease in vertical pupil size was significant.

Surgical treatment of dacryocystitis caused by cystic dilatation of the nasolacrimal system in three dogs.

A 4-year-old castrated male Golden Retriever was referred for evaluation of intermittent purulent discharge from the right eye of 4-months' duration. A radiolucent area in the maxillary bone was detected on examination of skull radiographs. Dacryocystorhinography revealed pooling of contrast material in the radiolucent area. A rhinotomy was performed, and a large opening between the cystic structure of the nasolacrimal system and the nasal cavity was created. Epiphora resolved after surgery and had not recurred by 9 months after surgery. Two other dogs had cystic structures of the nasolacrimal system and were treated surgically to allow drainage into the nasal cavity.

Penetrating keratoplasty for treatment of recurrent squamous cell carcinoma of the cornea in a horse.

Squamous cell carcinoma involving the cornea and conjunctiva of the left eye in a 14-year-old horse was treated by superficial keratectomy in combination with beta-radiation and radiofrequency hyperthermia. The tumor recurred 4 months later in the central cornea at the edge of the previous keratectomy site. Penetrating keratoplasty was performed in an effort to remove the tumor and retain a visual eye. The eye was visual 13 months after surgery. Mild fibrosis and vascularization were observed in the area of the penetrating keratoplasty.

Traumatic ocular proptoses in dogs and cats: 84 cases (1980-1993).

Eighteen eyes of 66 dogs were visual on reevaluation of traumatic proptosis. Twenty-one eyes were enucleated, and 4 dogs were euthanatized. In 18 cats, no eyes regained vision after traumatic proptosis: 12 cats had the affected eye enucleated, 2 had an eye that was considered blind, and 4 cats were euthanatized. Affected eyes of 45 dogs and 2 cats underwent surgical replacement and temporary tarsorrhaphy. Favorable prognostic indicators for eyes undergoing surgical replacement included proptosis in a brachycephalic dog, positive direct or consensual pupillary light response, normal findings on posterior segment examination, and a proptosed eye that had vision on initial examination. Unfavorable prognostic indicators included proptosis in a nonbrachycephalic dog, proptosis in cats, hyphema, no visible pupil, facial fractures, optic nerve damage, and avulsion of 3 or more extraocular muscles.

Effect of auriculopalpebral nerve block and intravenous administration of xylazine on intraocular pressure and corneal thickness in horses.

Intraocular pressure (IOP) was measured, using applanation tonometry, in both eyes of 20 horses after topical application of 0.5% proparacaine to the cornea. Ultrasonic pachymetry was used to measure central, mid-peripheral, and peripheral corneal thickness (CT) in all 4 quadrants of both eyes of 25 horses. All measurements were repeated after auriculopalpebral nerve block, sedation by IV administration of xylazine, or combination of nerve block and sedation. Mean IOP after topical anesthesia of the cornea was 20.6 +/- 4.7 mm of Hg for the left eye and 20.35 +/- 3.7 mm of Hg for the right eye. Mean central CT was 793.2 +/- 42.3 microns. The peripheral part of the cornea was significantly (P < 0.05) thicker, on average, than the central part of the cornea. Auriculopalpebral nerve block had no significant effect on IOP or CT. Intravenous administration of xylazine resulted in a significant (P < 0.05) decrease in IOP, but had no effect on CT.

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.

Lens-induced uveitis in dogs: 151 cases (1985-1990).

During a 5-year period, phacolytic uveitis was diagnosed in 202 eyes of 151 dogs admitted to the veterinary teaching hospital. The diagnosis of phacolytic uveitis was based on the finding of a cataractous lens and anterior uveitis, unassociated with other identifiable causes of uveal inflammation. The most commonly affected breeds were the Toy and Miniature Poodle (35%) and the American Cocker Spaniel (19%). The mean age was 7.0 years for all breeds, 5.1 years for the Cocker Spaniel, and 9.0 years for the Poodle breeds. Evidence of cataract resorption was visible in 72% of the eyes. Fifty-one dogs were affected bilaterally and 100 dogs unilaterally. The mean interval between recognition of the cataract and the onset of lens-induced uveitis (LIU) was 17 months; mean times of 25 and 11 months were seen in the Poodle breeds and American Cocker Spaniel, respectively. The mean age of dogs requiring greater than 1 revisit before the inflammation had subsided was 5.5 years. Complications, referable to the uveitis, were seen in 14% of eyes, the most important of which were glaucoma (16 eyes) and phthisis bulbi (9 eyes). Lens extraction surgery was done on 50 LIU-affected eyes, and on 35 normal eyes in LIU-affected animals. The 2- and 6-month success rates for LIU-affected eyes were 78 and 39%, respectively, and for normal eyes in LIU-affected animals were 85 and 71%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)