Ophthalmic examination findings in a colony of Screech owls (Megascops asio).

OBJECTIVE: To report ophthalmic findings in the Screech owl (Megascops asio). Sample population Twenty-three, apparently healthy adult captive Screech owls in Maryland. PROCEDURES: OU of all owls underwent complete ophthalmic examination. One randomly assigned eye of each bird was measured by phenol red thread tear test (PRT), and the other eye by Schirmer tear test (STT). TonoVet rebound tonometry and TonoPen-XL applanation tonometry were performed in each eye to measure IOP. Conjunctival swabs were cultured from one eye of 10 birds, corneal diameter was measured in OU of eight birds, and streak retinoscopy was performed on OU of seven birds. Ten birds were anesthetized, and A-scan ultrasonography using a 15-MHz probe was performed to obtain axial intraocular measurements. RESULTS: Ophthalmic abnormalities were noted in 24/46 (52%) of eyes. Median STT result was < or = 2 mm/min, ranging < or = 2-6 mm/min, and mean +/- SD PRT was 15 +/- 4.3 mm/15 s. Mean +/- SD IOP were 9 +/- 1.8 mmHg TonoVet-P, 14 +/- 2.4 mmHg TonoVet-D, and 11 +/- 1.9 mmHg TonoPen-XL. Coagulase negative staphylococcal organisms were cultured from all conjunctival swabs. Mean +/- SD corneal dimensions were 14.5 +/- 0.5 mm vertically and 15.25 +/- 0.5 mm horizontally. All refracted birds were within one diopter of emmetropia. Mean +/- SD axial distance from the cornea to the anterior lens capsule was 4.03 +/- 0.3 mm, from cornea to the posterior lens capsule was 10.8 +/- 0.5 mm, and from cornea to sclera was 20.33 +/- 0.6 mm. CONCLUSIONS: This study reports ophthalmic examination findings in Screech owls, and provide means and ranges for various ocular measurements. This is the first report of rebound tonometry and PRT in owls.

Cardiovascular effects of topical ophthalmic 10% phenylephrine in dogs.

OBJECTIVE: To evaluate the effect of topical ophthalmic 10% phenylephrine on systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), pulse rate (PR) and electrocardiogram (ECG) in dogs. ANIMALS STUDIED: Nine clinically normal dogs. PROCEDURE: Arterial catheters were placed in the dorsal pedal artery of awake dogs and ECG leads were attached. After a 15-min acclimatization period, baseline PR, SAP, DAP and MAP were recorded every 5 min for 20 min. Two treatment groups (eight dogs each) were studied. Group I: one drop of phenylephrine was placed in each eye once. Group II: one drop of phenylephrine was placed in each eye three times at 5-min intervals. Following treatment, PR, SAP, DAP and MAP were recorded every 5 min for 90 min. The mixed procedure of the SAS system was used to perform a repeated measures analysis of variance to test for linear and quadratic trends across time. RESULTS: Group I: There was a significant quadratic decrease in PR across time (P = 0.0051). Systolic arterial pressure increased linearly with time (P = 0.0002), MAP increased linearly with time (P = 0.0131), and DAP increased linearly with time (P = 0.0001). Group II: There was a significant quadratic decrease in PR across time (P = 0.0023). There was a significant quadratic increase in SAP (P = 0.0324), MAP (P = 0.0103) and DAP (P = 0.0131) across time. CONCLUSIONS: Topical ophthalmic application of 10% phenylephrine in normal dogs results in elevation of arterial blood pressure and reflex bradycardia.

Feline leukemia virus detection in corneal tissues of cats by polymerase chain reaction and immunohistochemistry.

OBJECTIVES: To determine the presence of feline leukemia virus (FeLV) in the corneas of FeLV-infected cats. ANIMALS STUDIED: Thirty-four random source cats. PROCEDURES: Seventeen cats were found positive for FeLV serum p27 antigen by enzyme-linked immunosorbent assay (ELISA). Twelve ELISA positive cats were also positive on peripheral blood samples by immunofluorescent antibody (IFA) testing. Seventeen ELISA negative cats served as negative controls. Full thickness corneal specimens were collected from the left cornea of all cats and analyzed for FeLV proviral DNA and gp70 antigen by polymerase chain reaction (PCR) and immunohistochemical (IHC) testing, respectively. RESULTS: Eleven (64.7%) positive corneal PCR results were obtained from 17 ELISA positive cats. Of 12 cats that were both ELISA and IFA positive on peripheral blood, 10 (83.3%) had positive corneal PCR results. All corneal tissues from ELISA negative cats were PCR negative. IHC staining of corneal sections revealed the presence of FeLV gp70 in corneal tissues of nine (52.9%) ELISA positive cats. Of the 12 cats that were both ELISA and IFA positive on peripheral blood, eight (66.7%) had positive corneal IHC results. Positive IHC staining was localized to the corneal epithelium. Corneal tissues of all ELISA negative cats and all IFA negative cats were negative on IHC testing. CONCLUSIONS: FeLV antigens and proviral DNA are present in corneal tissues of some FeLV-infected cats. Screening corneal donors for FeLV infection is warranted.

Evaluation of aqueous tear production in dogs following general anesthesia.

Pre- and postanesthetic Schirmer tear test (STT) values were measured in 46 dogs. All subjects had normal preanesthetic STT values (18.3 +/- 2.8 mm per min in the left eye [OS] and 18.3 +/- 3.0 mm per min in the right eye [OD]). Significant differences were found between pre- and postanesthetic STT values. Significant decreases in tear production were evident for up to 24 hours following the anesthetic event. Subject age did not significantly influence the results. Duration of anesthesia significantly affected the rate of return to preanesthetic STT values, with anesthetic events greater than two hours in duration having a prolonged effect as compared to anesthetic events less than two hours in duration. Anticholinergic administration prior to or during anesthesia further lowered postanesthetic STT values.

Effect of topical 1% atropine sulfate on intraocular pressure in normal horses.

OBJECTIVE: To determine the effect of topical 1% ophthalmic atropine sulfate on intraocular pressure (IOP) in ocular normotensive horses. Animals Studied Eleven clinically healthy horses. Procedures IOP was measured bilaterally twice daily, at 8 AM and 4 PM, for 5 days. No medication was applied for the first 2 days of the study. Thereafter, one eye of each horse was treated with 0.1 mL of topical 1% atropine sulfate ointment twice daily (7 AM and 7 PM) for 3 days. The contralateral eye served as a control. In eight of the horses, an additional IOP reading was taken 3 days following cessation of the atropine treatment. RESULTS: There was no significant difference in the IOP of control vs. treatment eyes in the pretreatment period, days 1 and 2 (P = 0.97 and 0.55, respectively). During the treatment period, treated eyes of 10 of the horses had significantly lower IOP than control eyes (P = 0.03). The mean IOP reduction in treated eyes, relative to untreated eyes, was 11.2%. One horse had a significant rise in IOP in the treated eye compared to the remaining study animals. The IOP of control eyes did not vary significantly over the observation period (P = 0.27). There was no significant variation in IOP between the 8 AM and 4 PM measurement (P = 0.9). CONCLUSIONS: Topical 1% atropine sulfate causes a small, but significant decline in IOP in most ocular normotensive horses. Because topical atropine may elevate IOP in some horses, it should be used with caution in the treatment of glaucoma in this species.

Primary lens luxation in the Chinese Shar Pei: clinical and hereditary characteristics.

A pedigree analysis of a family of 15 related Chinese Shar Peis was conducted. This pedigree analysis, including affected and nonaffected dams, sires and offspring, was compiled to document and characterize the occurrence, common clinical signs, and age of onset of primary lens luxation while suggesting a possible mode of inheritance in this breed. Of the five offspring from the mating of an affected dam to two unrelated affected males, 100% of offspring were affected with bilateral primary lens luxations. Of the four viable offspring from the mating of the same affected dam to an unrelated, unaffected male, two dogs (50%) were affected. The average age of onset of affected animals (seven) in this first generation was 4.9 years (range 3-6 years). The six dogs in the second generation of the same pedigree line were 2-years-old at examination with none of these animals affected at the time of this study. The most common presenting complaints were a unilateral change in ocular appearance (5 of 7 dogs) and subjective vision impairment (4 of 7 dogs). The most common clinical sign upon ophthalmic examination was iridodonesis (unilateral 4 of 7 dogs; bilateral 3 of 7 dogs) and the presence of an aphakic crescent (3 of 7 dogs). Gonioscopy and tonometry of severely affected eyes revealed a narrow or closed iridocorneal angle and ocular hypertension. This study suggests that primary lens luxation does occur in the Chinese Shar Pei, resembling the clinical condition (age of onset, clinical signs) previously described in the terrier breeds, the Border Collie, and the Tibetan Terrier. Application of the phenotypic findings in this study to a Mendelian genetic model of inheritance suggests that primary lens luxation in the Chinese Shar Pei is inherited as a simple autosomal recessive trait.

Argon laser trabeculoplasty and pilocarpine effects on outflow facility in the cynomolgus monkey.

PURPOSE: We sought to determine whether and how prior argon laser trabeculoplasty (ALT) alters outflow facility, the pilocarpine-induced facility increase, and the morphology of the trabecular meshwork in cynomolgus monkeys. METHODS: Eleven cynomolgus monkeys underwent unilateral 360 degrees argon laser trabeculoplasty, eight in two 180 degrees sessions (seven 3 months apart, one 11 days apart) and three in a single session. Intraocular pressure (IOP, Golmann ap-planation tonometry), aqueous humor flow rate (AHFR, fluorophotometry), total outflow facility (two-level constant pressure perfusion) and response to intracameral pilocarpine, and morphology (light and scanning/transmission electron microscopy) were determined at various times. RESULTS: Resting total perfusion outflow facility 3 and 6 months after 360 degrees ALT was 30% higher in ALT-treated than in contralateral untreated eyes. There were no consistent or statistically significant differences between ALT-treated and contralateral untreated eyes in (a) IOP or AHFR before ALT, 5 weeks after initial 180 ALT, or 5 weeks after the second 180 ALT; (b) post-intracameral pilocarpine facility, or the dose-dependent facility response to pilocarpine 10 weeks after the initial 180 ALT or 3 and 6 months after the second 180 ALT; or (c) light or electron microscopic appearance of the trabecular meshwork or inner wall of Schlemm's canal 3-17 months after 360 ALT. CONCLUSIONS: This study indicates that (a) ALT alters the biomechanical properties of the monkey trabecular meshwork so as to modestly increase its hydraulic conductivity without affecting the facility response to pilocarpine-induced ciliary muscle contraction; and (b) young healthy monkey outflow tissues exhibit remarkable reparative and homeostatic capabilities.

Comparison of kittens fed queen's milk with those fed milk replacers.

Fifteen 2-week-old kittens were randomly assigned to 1 of 3 milk treatment groups as the sole source of nutrition for 4 weeks: queen's milk, commercially available kitten milk replacer (CMR), and an experimental milk replacer (EXP). Kittens fed queen's milk suckled ad libitum, whereas CMR- and EXP-fed kittens were tube-fed every 6 hours. Kittens were weaned at 6 weeks of age and were fed a feline growth diet ad libitum for an additional 4 weeks. Kittens were examined at 2, 4, 6, 8 and 10 weeks of age; the procedure included an ophthalmic examination and blood sample collection for CBC and serum biochemical and amino acid analyses. Kittens fed CMR and EXP diets had weight gain greater than that for queen's milk-fed kittens. The kittens fed CMR, however, had diarrhea throughout most of the milk-feeding trial and developed diffuse anterior and posterior lens opacification and vacuolation at the posterior Y-sutures. The lens opacities noticed in the kittens during the milk treatments resolved to a residual perinuclear halo, and a few incipient cortical opacities were observed by the end of the growth diet-feeding period. Serum arginine concentration was significantly (P < or = 0.05) lower in the CMR-fed kittens, but was not different during the growth diet-feeding period. We concluded that the EXP diet supported normal growth in 2- to 6-week-old kittens; CMR supported normal kitten growth rate, but resulted in diarrhea and cataract formation; and serum amino acid data indicated that low arginine concentration may have been related to the CMR-induced cataract formation.

Comparison of the human and canine Schiotz tonometry conversion tables in clinically normal dogs.

Intraocular pressure (IOP) was measured in 114 eyes of 57 clinically normal dogs with 2 applanation tonometers (Tono-Pen and Mackay-Marg) and the Schiotz indentation tonometer, using the 5.5- and 7.5-g weights. Significant differences were not detected between measurements obtained with the Tono-Pen and Mackay-Marg tonometers the Mackay-Marg and Schiotz tonometers using either weight and conversion with the human calibration table, or the Tono-Pen and Schiotz tonometers using the 7.5-g weight and the human calibration table. Values obtained by use of the Tono-Pen tonometer were significantly less (P less than 0.005) than values obtained with the Schiotz tonometer when a 5.5-g weight and the human calibration table were used, but the amount was clinically unimportant. Estimates of IOP using the Schiotz tonometer and the canine calibration table, and either the 5.5- or 7.5-g weight were clinically and significantly much higher (P less than 0.0001) than estimates obtained with the Tono-Pen, Mackay-Marg, or Schiotz tonometers, using the human calibration table and either weight. Sixty to 70% of clinically normal dogs had an IOP greater than or equal to 30 mm of Hg when Schiotz scale measurements were converted with the canine conversion table. For clinically normal dogs, the human calibration table was the most clinically useful table for converting Schiotz tonometer measurements to mm of Hg. Normal mean (+/- SD) canine readings with the Schiotz tonometer and the 5.5-g weight was 4.9 +/- 1.5 tonometer scale units (range, 2 to 11; 95% confidence interval, 1.9 to 7.9).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the human and canine Schiotz tonometry conversion tables in clinically normal cats.

Intraocular pressure (IOP) was measured in 73 eyes of 37 clinically normal cats with 2 applanation tonometers (Tono-Pen and Mackay-Marg) and the Schiotz indentation tonometer, using the 5.5- and 7.5-g weights. Statistically, the Tono-Pen tonometer underestimated IOP compared with the values obtained by use of the Mackay-Marg tonometer (P less than 0.0001) and the Schiotz tonometer, with either weight and either the human (P less than 0.01) or the canine (P less than 0.0001) calibration tables. Estimates of IOP using the human calibration table and either the 5.5- or 7.5-g weight were not significantly different from each other or from those obtained with the Mackay-Marg tonometer. Schiotz measurements obtained with either weight and converted using the canine calibration table were not only significantly (P less than 0.0001) different from each other, but were also clinically and significantly (P less than 0.0001) higher than measurements obtained with the Tono-Pen and Mackay-Marg tonometers or the Schiotz tonometer, using the human calibration table and either weight. Approximately three quarters of clinically normal cats had an IOP greater than or equal to 30 mm of Hg when Schiotz tonometer measurements were converted with the canine conversion table. The human calibration table was the most clinically useful table for converting Schiotz measurements from clinically normal feline eyes to estimates of IOP in mm of Hg. Normal mean (+/- SD) feline readings with the Schiotz tonometer and the 5.5-g weight was 3.9 +/- 1.4 tonometer scale units (range, 1.0 to 7.5; 95% confidence interval [CI], 1.1 to 6.7).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of two applanation tonometers in cats.

Comparisons of the MacKay-Marg and Tono-Pen applanation tonometers in open and closed in vitro systems were made for the eyes of cats. Both instruments significantly underestimated intraocular pressure (IOP) vs direct manometry (P less than 0.001), but in readily predictable manner, with high coefficients of determination (r2 = 0.99). For tonometer 1 (MacKay-Marg), calculated actual IOP = 1.36 x (MacKay-Marg measurement) - 1.67 mm of Hg; and for tonometer 2 (Tono-Pen), calculated actual IOP = 1.37 x (Tono-Pen measurement) + 0.8 mm of HG, using measurements from 11 enucleated eyes. In vivo comparisons were initially made in 81 clinically normal eyes (n = 41 cats) by applying the Tono-Pen first followed by the MacKay-Marg. Compared with the MacKay-Marg, the Tono-Pen significantly (P less than 0.001) underestimated IOP in these cats. When the order of tonometer applanation was subsequently reversed in 73 clinically normal eyes (n = 37 cats) the Tono-Pen again significantly (P less than 0.001) underestimated IOP, compared with the MacKay-Marg. Alterations in tonometer order did not result in significant differences in measured IOP for the MacKay-Marg when compared with itself, but Tono-Pen measurements were significantly (P less than 0.05) less when its use followed, rather than preceded, that of the MacKay-Marg. Mean (+/- SD) IOP in clinically normal cats when each tonometer was used first was 22.6 +/- 4.0 mm of Hg (range, 14 to 32 mm of Hg) for the MacKay-Marg and 19.7 +/- 5.6 mm of Hg (9 to 31 mm of Hg) for the Tono-Pen.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of two applanation tonometers in horses.

Comparisons were made of measurements obtained in horses, using 2 applanation tonometers in vivo and in vitro. In vitro comparisons indicated that although neither instrument accurately recorded intraocular pressure (IOP), compared with manometric measurements, results of both instruments indicated linear digression from manometric IOP values that could readily be corrected, thereby accurately estimating IOP in horses. For tonometer 1 (MacKay-Marg), calculated actual IOP = 1.48 - 0.9 mm of Hg; and for tonometer 2 (Tono-Pen), calculated actual IOP = 1.38 + 2.3 mm of Hg. The coefficients of determination (r2) values were markedly high (0.99 for both equations). In vivo comparisons in clinically normal horses did not reveal significant differences in measured IOP between the 2 instruments, and IOP was not altered from baseline after auriculopalpebral nerve block. Mean (+/- SD) IOP in clinically normal horses was 23.5 +/- 6.10 mm of Hg and 23.3 +/- 6.89 mm of Hg, for tonometers 1 and 2, respectively.

Comparison of serum and plasma taurine values in Bengal tigers with values in taurine-sufficient and -deficient domestic cats.

A white Bengal tiger was determined to have a central retinal lesion and a central visual defect. Because of the known association between feline central retinal degeneration (CRD) and taurine deficiency in domestic cats, plasma concentrations of taurine were measured in this tiger. Serum concentrations of taurine, methionine, and cystine also were measured in white Bengal tigers, orange Bengal tigers, taurine-sufficient domestic cats, and taurine-deprived and tissue-taurine-depleted visually impaired cats with CRD. Hepatic and brain enzymes responsible for taurine synthesis were identified in tissue specimens from an orange Bengal tiger. Serum taurine concentrations were lower in white vs orange tigers, but were not as low as those in cats with CRD. Thus, we concluded that taurine depletion did not account for the central retinal lesion in the white Bengal tiger.

Management of facial injuries.

Because of the excellent blood supply to the head region, superficial lacerations to the soft tissue structures of the head generally heal rapidly without treatment. Lacerations of the equine tongue frequently go unnoticed because difficulty in eating usually is not apparent. The majority of lacerations heal if left untreated, with no loss in function. Surgical repair is indicated to promote healing and prevent deformity, to amputate a severely compromised apex, and to alter a scar or defect that is unacceptable to the owner. Surgical principles to be adhered to include thorough debridement and copious lavage, multiple layer closure, and placement of tension sutures away from the primary suture line and tied on the dorsum of the tongue. Full-thickness lip lacerations should be repaired using multiple-layer closure and tension sutures tied on the skin surface away from the primary suture line. Reconstructive techniques have been described for extensive lip lacerations when primary repair was inadequate or tissue loss was severe. Thorough evaluation of the equine lid, adnexa, and orbit is essential in determining severity of injury and appropriate treatment methods as well as for establishment of a prognosis. The injury may be minor or more severe, leading to blindness, disfigurement, or loss of the eye itself. Depression fractures involving the frontal, maxillary, or nasal bones are frequently open fractures. Skin abrasions, epistaxis, facial deformity, crepitus, and pain are clinical signs seen with this type of injury. Bone and soft tissue reconstruction should be performed to minimize potential complications. Facial fractures left untreated can result in facial deformity, sequestration, sinusitis, and osteomyelitis.

Pseudallescheria boydii keratomycosis in a horse.

The fungal organism Pseudallescheria boydii was isolated from the cornea of a Quarter Horse with ulcerative keratitis. Despite aggressive hourly medication through a subpalpebral lavage system, with drugs including miconazole and natamycin, the cornea developed a stromal abscess. Orbital exenteration was performed after 3 weeks. The fungal isolate was later determined to be resistant to all 8 antifungal drugs tested. Microscopic examination of the cornea revealed fungal hyphae throughout the corneal stroma and penetrating the Descemet membrane. Pseudallescheria boydii has not been implicated previously as a cause of keratomycosis in horses or in other domestic animals, although cases in human beings have been described.

Zygomatic salivary gland mucocele in a ferret.

A zygomatic salivary gland mucocele was diagnosed in a 1-year-old female domestic ferret with exophthalmos. A T-shaped incision from near the lateral canthus to the base of the ear and continuing ventrally to the level of the commissure of the mouth was made to expose the mucocele. Surgical removal was complicated by the large open orbit of the ferret, adjacent cellulitis, extension ventromedial to the globe, and difficulty in identifying important motor nerves. Vision was maintained, but slight postoperative enophthalmos and mild upper eyelid paresis developed.

Arthritis and panuveitis as manifestations of Borrelia burgdorferi infection in a Wisconsin pony.

Infection with Borrelia burgdorferi caused panuveitis and arthritis in a pony. Spirochetes were detected by direct immunofluorescence in the anterior chamber of the eye. The carpal joints had severe degenerative joint disease, with synovial proliferation. The synovium and serum had B burgdorferi antibody titers of 1:1024. The pony lived in an area of Wisconsin where infection with B burgdorferi is endemic in human beings. Previously, serum antibodies to B burgdorferi had been found in horses, but disease had not been reported.