Intraocular pressure and Schirmer tear test results in clinically normal Long-Eared Hedgehogs (Hemiechinus auritus): reference values

Objective The present study was undertaken to establish reference values for Schirmer tear test (STT) and intraocular pressure (IOP) in the long‐eared hedgehog (Hemiechinus auritus). Animals Fourteen healthy long‐eared hedgehogs (H. auritus) of either sex were studied. Procedures The hedgehogs were individually immobilized with an intramuscular injection of combined Ketamine (20 mg/kg) and Diazepam (0.5 mg/kg), and each animal underwent ophthalmic examinations including: STT, tonometry, biomicroscopy, and indirect ophthalmoscopy. Results No significant effects of animal gender, weight, side (right vs. left eye) were found in this study. Mean (SD) STT values for all eyes (n = 28) were 1.7 ± 1.2 mm/1 min with a range of 0–4 mm/1 min. Mean STT in male animals was 2.2 ± 1.2. Mean STT in female Hedgehogs was 1.3 ± 1.1. Mean (SD) IOP values by applanation tonometry were 20.1 ± 4.0 mmHg (range 11.5–26.5 mmHg). Mean (SD) IOP values by applanation tonometry were 18.2 ± 4.0 and 22.0 ± 3.2 mmHg for males and females, respectively. Conclusions This study reports STT and IOP findings in long‐eared hedgehogs (H. auritus).     

Effect of anesthetic induction with propofol,alfaxalone or ketamine on intraocular pressure in cats: a randomized masked clinical investigation

ObjectiveTo compare the effect of propofol, alfaxalone and ketamine on intraocular pressure (IOP) in cats.Study designProspective, masked, randomized clinical trial.AnimalsA total of 43 ophthalmologically normal cats scheduled to undergo general anesthesia for various procedures.MethodsFollowing baseline IOP measurements using applanation tonometry, anesthesia was induced with propofol (n = 15), alfaxalone (n = 14) or ketamine (n = 14) administered intravenously to effect. Then, midazolam (0.3 mg kg^?1) was administered intravenously and endotracheal intubation was performed without application of topical anesthesia. The IOP was measured following each intervention. Data was analyzed using one-way anova and repeated-measures mixed design with post hoc analysis. A p-value <0.05 was considered significant.ResultsMean ± standard error IOP at baseline was not different among groups (propofol, 18 ± 0.6; alfaxalone, 18 ± 0.7; ketamine, 17 ± 0.5 mmHg). Following induction of anesthesia, IOP increased significantly compared with baseline in the propofol (20 ± 0.7 mmHg), but not in the alfaxalone (19 ± 0.8 mmHg) or ketamine (16 ± 0.7 mmHg) groups. Midazolam administration resulted in significant decrease from the previous measurement in the alfaxalone group (16 ± 0.7 mmHg), but not in the propofol group (19 ± 0.7 mmHg) or the ketamine (16 ± 0.8 mmHg) group. A further decrease was measured after intubation in the alfaxalone group (15 ± 0.9 mmHg).Conclusions and clinical relevancePropofol should be used with caution in cats predisposed to perforation or glaucoma, as any increase in IOP should be avoided.     

Reference values for selected ophthalmic diagnostic tests and clinical characteristics of chinchilla eyes (Chinchilla lanigera)

Objective To establish reference values for the Schirmer tear test I (STT I), the phenol red thread tear test (PRTT), the intraocular pressure (IOP) with rebound tonometry, to determine the corneal sensitivity for healthy chinchillas, and to describe clinical aspects of normal chinchilla eyes. Animals One hundred and twenty‐two eyes of 61 healthy pet chinchillas of different age and gender were investigated. Procedures A full ophthalmic exam including slit lamp biomicroscopy, ophthalmoscopy, measurement of STT I, PRTT, determination of the corneal touch threshold (CTT), and the measurement of the IOP (TonoVet®) was performed. The normal appearance of the lid, the iris, the lens, the fundus, and the optic nerve disc was evaluated. Results The results of the STT I were very low and not reliable, and the measurement was discontinued. The median value of PRTT was 14.0 mm wetting/15 s (mean 14.6 ± 3.5 mm wetting/15 s). The median CTT was 32.5 mm (mean 31.2 ± 7.0 mm) respectively 1.2 g/mm² (mean 1.5 ± 0.9 g/mm²). The median IOP was 3.0 mmHg (mean 2.9 ± 1.8 mmHg). The predominating iris color was brown. The fundus pigmentation varied. Few lens alteration were seen in otherwise healthy chinchilla eyes. Most chinchillas had myelinated discs. Optic nerve cupping was present in 62% of the animals. Conclusion Because of the small amount of tears, the PRT test is recommended for tear measurements in chinchillas. The IOP in chinchillas seems to be quiet is low in comparison to other rodents.     

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 ≤ 2 mm/min, ranging ≤ 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.     

Reference values for Schirmer tear tests I and II in clinically normal pigs

Objective To determine reference values for Schirmer tear tests I and II in clinically normal pigs. Animal studied Twenty clinically normal Landrace pigs (10 males and females) without ocular abnormalities were used in this study. Procedures In all pigs, Schirmer tear tests (STT) I and II were performed by using a sterile Schirmer tear test standardized strip (Schirmer‐Tränentest^®, Germany) placed in the lower conjunctival fornix for 1 min. Results For each test (STT I and STT II), no differences were observed between the right and left eyes (P ≥ 0.5). The mean ± SD STT I value was 15.6 ± 3.7 mm/min (range, 10–22 mm/min), while the mean STT II value was 12.4 ± 3.8 mm/minute (range, 5–18 mm/min). The mean STT II value was significantly lower than the STT I level (P < 0.001). Animal gender did not have a significant effect on STT I and II values (P = 0.52). The mean ± SD STT I/II values of 10 juvenile pigs were significantly lower than the mean ± SD STT I/II values of 10 adult pigs (P < 0.001). Conclusions This study of 20 Landrace pigs provided valuable information on normal STT I/II in this species. Knowledge of normal STT reference values in pigs enables the clinician to evaluate corneal pathology and diagnose tear deficiency syndromes with greater accuracy.     

The effects of ketamine‐midazolam anesthesia on intraocular pressure in clinically normal dogs

Objective To determine the effects of intravenous ketamine‐midazolam anesthesia on intraocular pressure (IOP) in ocular normotensive dogs. Animals Thirteen adult mixed‐breed dogs. Procedures Dogs were randomly assigned to treatment (n = 7) and control (n = 6) groups. Dogs in the treatment group received intravenous ketamine 15 mg/kg and midazolam 0.2 mg/kg and dogs in the control group received intravenous saline. The time of intravenous drug injection was recorded (T₀). Measurements of IOP were then repeated 5 min (T₅) and 20 min (T₂₀) following the intravenous administration of ketamine‐midazolam combination and saline in both groups. Results Measurements showed normal IOP values in both groups. The mean ± SD baseline IOP values for treatment and control groups were 13.00 ± 1.47 and 10.33 ± 2.20, respectively. For baseline IOP values, there was no significant difference between treatment and control groups (P = 0.162). In the treatment group, the subsequent post‐treatment mean ± SD values were 15.64 ± 2.17 (5 min), and 14.92 ± 1.98 (20 min). There was no evidence of statistical difference between baseline values and post‐treatment values after treatment with ketamine‐midazolam (P₅ = 0.139; P₂₀ = 0.442). In control eyes, the mean ± SD values at 5 and 20 min were 10.41 ± 2.01 and 10.16 ± 1.69, respectively. There was no significant difference between baseline values and post‐treatment values in control group (P₅ = 1.000; P₂₀ = 1.000). Conclusion Ketamine‐midazolam combination has no clinically significant effect on IOP in the dog.     

The effects of ketamine hydrochloride and diazepam on the intraocular pressure and pupil diameter of the dog’s eye

Objective To determine the effects of 10% ketamine hydrochloride and 0.5% diazepam on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the canine eye. Procedures Ten healthy dogs for each treatment group were used in this study. In the first group, 20 mg/kg ketamine hydrochloride was injected intravenously; in the second, 0.5 mg/kg diazepam was similarly injected; and in the third, a control group, 0.9% saline was used. In all groups, IOP and HPD were measured every 5 min for 35 min in the first group, and 60 min in the second and third group. Results A maximum increase in IOP was obtained 5 min after ketamine injection, with IOP of 23.2 ± 5.8 mmHg (a 45.0% increase compared to baseline) in the right eye and 22.9 ± 5.9 mmHg (a 43.5% increase) in the left eye (both significant at P < 0.01). A significant IOP increase was observed throughout the research period of 35 min. Statistically significant increases in HPD (P < 0.05) were observed only at 5 and 25 min after ketamine injection. A significant increase in IOP was obtained 10 min after diazepam injection, showing a maximum IOP 20 ± 5.0 mmHg in the right eye (9.3% increase) and 19.9 ± 5.1 mmHg (8.7% increase) in the left eye (both significant at P < 0.05). HPD decreased during the study period, reaching the lowest level 30 min post‐treatment. Conclusions This study showed a substantial increase in IOP after ketamine injection and a less substantial, but still significant increase after diazepam injection. These findings should be taken into consideration when using these drugs in dogs with fragile corneas, or in dogs predisposed or affected by glaucoma.     

Results of Schirmer tear test in clinically normal llamas (Lama glama)

Purpose To determine the normal reference range for Schirmer tear test (STT) values in clinically normal llamas (Lama glama) Animals Nine captive llamas (Lama glama) (seven females and two males) were used in this study. Procedure Complete ophthalmic examinations were performed without chemical restraint. STT I values were evaluated in both eyes of all llamas using a commercial STT strip of a single lot number (Schirmer‐Tränentest^®, Germany). STT II value was also measured in both eyes of seven female llamas. Results No statistically significant differences among ages or between right and left eyes were found for any of the results. The mean ± SD STT I of 18 eyes of nine llamas was 17.3 ± 1.1 mm/min (Range 15–19 mm/min). The mean ± SD STT II of 14 eyes of seven llamas was 15.4 ± 1.7 mm/min (Range 12.5–17.5 mm/min). A paired samples t‐test demonstrated that there was a significant difference between the STT I and II values (P = 0.001). Conclusion This study provides novel data for normal reference ranges of STT I and II values in healthy llamas. Results of this study may assist veterinarians in the diagnosis of ocular surface disease and syndromes affecting the tear film in these species.     

Effect of central corneal thickness on intraocular pressure with the rebound tonometer and the applanation tonometer in normal dogs

Objective To evaluate the effect of central corneal thickness (CCT) on the measurement of intraocular pressure (IOP) with the rebound (TonoVet^®) and applanation (TonoPen XL^®) tonometers in beagle dogs. Animal studied Both eyes of 60 clinically normal dogs were used. Procedures The IOP was measured by the TonoVet^®, followed by the TonoPen XL^® in half of the dogs, while the other half was measured in the reverse order. All CCT measurements were performed 10 min after the use of the second tonometer. Results The mean IOP value measured by the TonoVet^® (16.9 ± 3.7 mmHg) was significantly higher than the TonoPen XL^® (11.6 ± 2.7 mmHg; P < 0.001). The IOP values obtained by both tonometers were correlated in the regression analysis (γ² = 0.4393, P < 0.001). Bland–Altman analysis showed that the lower and upper limits of agreement between the two devices were ?0.1 and +10.8 mmHg, respectively. The mean CCT was 549.7 ± 51.0 μm. There was a correlation between the IOP values obtained by the two tonometers and CCT readings in the regression analysis (TonoVet^® : P = 0.002, TonoPen XL^® : P = 0.035). The regression equation demonstrated that for every 100 μm increase in CCT, there was an elevation of 1 and 2 mmHg in IOP measured by the TonoPen XL^® and TonoVet^®, respectively. Conclusions The IOP obtained by the TonoVet^® and TonoPen XL^® would be affected by variations in the CCT. Therefore, the CCT should be considered when interpreting IOP values measured by tonometers in dogs.     

A COMPARISON OF ALFAXALONE AND TRICAINE METHANESULPHONATE (MS-222) IN TWO FISH SPECIES

The purpose of this study was to evaluate the effectiveness of the alfaxalone formulation Alfaxan? as an immersion anesthetic in tropical fish species compared to that of tricaine methanesulfonate (MS-222). 22 black spot barbs (Puntius filamentosis) measuring (mean±SD) 11.4 ±1.4 cm in body length and 22 peacock cichlids (Aulonocara spp.) (measuring 8.4 ± 1.6cm were anesthetized in water baths containing 100 mg/L of MS-222 buffered with 200 mg/L of bicarbonate or 5 mg/L of alfaxalone following a 2-week washout period. Time to maximum effect, recovery periods, self-righting, spontaneous swimming movements, opercular movements, and response to noxious stimuli were recorded. The following results are for the black spot barbs following MS-222 and alfaxalone anesthesia, respectively: mean times (±SD) to surgical anesthesia were 5.5 ± 2.11 and 3.27 ± 1.72 minutes and mean recovery times were 2.95 ± 0.9 and 9.14 ± 3.15 minutes. The peacock cichlid anesthetic protocols for MS-222 (20 of 22 cichlids) and alfaxalone (20 of 21 cichlids) produced the following results, respectively: mean times (±SD) to surgical anesthesia were 14.75 ±5.43 and 11.1 ± 9.84 minutes and mean recovery times were 3.6 ±0.82 and 22.4 ±11.3 minutes. Median recovery time from 5 mg/L alfaxalone was significantly longer (P < 0.001) in both species, by 5 minutes for black spot barbs and by 17 minutes for peacock cichlids. Variation in induction and recovery times between species was observed, with black spot barbs having significantly (P < 0.0001) faster induction times when treated with both drugs, and a faster recovery time from 5 mg/L alfaxalone.     

Tonometry in adult yellow-footed tortoises (Geochelone denticulata)

Objective To determine intraocular pressure (IOP) in adult yellow‐footed tortoises using applanation tonometry. Animals Fifteen healthy adult captive yellow‐footed tortoises (eight males and seven females). Procedures Intraocular pressures were estimated for tortoises by using an applanation tonometer after topical anesthesia. Body length, measured from nuchal to anal scutes, ranged from 27.5 to 57.2 cm. Five measurements from each eye were obtained by a single observer in an ambient temperature of approximately 30 °C. Results Mean ± SEM IOP of 30 eyes of 15 yellow‐footed tortoises was 14.2 ± 1.2 mmHg. Range of IOP was 6–30 mmHg for tortoises. Significant differences were detected neither between right and left eyes (P = 0.357) of individual tortoises, nor between males and females (P = 0.524). Observer's readability was good (intraclass coefficient = 0.65), and IOP did not change over the ordered five measurements. Conclusions There was no significant difference in IOP between males and females in this specie. Tonometry values for normal eyes may represent a useful diagnostic methodology for recognition and treatment of ocular diseases in reptiles.     

Effect of Coherin™ on intraocular pressure,pupil size and heart rate in the glaucomatous Beagle: a pilot study

Objective To evaluate effects of Coherin? on intraocular pressure (IOP), pupil size (PS), and heart rate (HR) in glaucomatous Beagles in single‐dose studies in a pilot study. Materials and methods Intraocular pressure, PS, and HR were measured in eight glaucomatous Beagles. One randomly chosen eye received single 50 μL doses of differing concentrations of Coherin? (treated eye) or vehicle (placebo‐treated eye), and the fellow eye served as the untreated control. After the first measurements, a single dose of either Coherin? or sterile water vehicle was instilled in the drug and placebo eyes, respectively. Results The mean ± SEM diurnal changes in IOP after 0.005%, 0.01%, 0.2%, 0.284%, 1%, 2%, and 4% topical Coherin? once daily were 7.6 ± 3.2 mmHg, 15.5 ± 5.3 mmHg, 11.2 ± 4.4 mmHg, 11.8 ± 4.4 mmHg, 19.1 ± 3.8 mmHg, 5.0 ± 1.8 mmHg, and 8.8 ± 2.8 mmHg, respectively. The declines in IOP were significantly different (P < 0.05) from the untreated control eyes with the 0.2% and 0.284% Coherin?‐treated eyes and suggestive for 1% Coherin? concentrations. No signs of irritation, significant PS, and HR changes were detected in the Coherin?‐treated eyes. Conclusion Of seven different concentrations, 2% and 0.248% Coherin? produced significant declines in IOP in the glaucomatous beagle in single‐dose studies when compared to both untreated control and placebo‐treated eyes. One percent Coherin? solution produced significant IOP decreases compared with the placebo‐treated eye but not the untreated control eyes. No local ocular irritation, PS and HR changes were observed in Coherin?‐treated eyes. This pilot study suggests that topical Coherin? has potential as an ocular hypotensive agent.     

Time-specific intraocular pressure curves in Rhesus macaques (Macaca mulatta) with laser-induced ocular hypertension

Objective To detect and categorize time‐specific variations in daytime intraocular pressure (IOP) found in Rhesus monkeys with laser‐induced ocular hypertension. Procedures Ten male monkeys with argon laser‐induced ocular hypertension in one eye were anesthetized with ketamine hydrochloride, and the IOP measured in both eyes at 7 a.m., 7.30 a.m., and then hourly until 1 p.m. with a Tonopen? XL applanation tonometer. Intraocular pressure time profiles for both eyes in each animal were developed. The means ± SD of the IOPs for both eyes were calculated for the whole 6‐h study period, and the values compared statistically. The difference between the lasered eye mean IOP standard deviation and the normal eye mean IOP standard deviation for each animal during the 6‐h follow‐up was also calculated and compared. Results Mean IOP (± SD) in the glaucoma and normal eyes for the 10 animals during the 6‐h study was 32.6 ± 2.5 and 14.9 ± 2.5 mmHg, respectively. The IOP was significantly higher in the experimental eye than in the normal eye (P = 0.0008). The mean IOP in the lasered eye did not significantly change during the study period, whereas a slight but significant increase in IOP of the normal eye over the study period was recorded (P = 0.003). The variance in IOP in the hypertensive eyes was considerably greater than that in the untreated control eyes. From 7 a.m. to 1 p.m. the IOP declined in five eyes and increased in the other five eyes with laser‐induced ocular hypertension. Conclusions The time‐specific IOP variation pattern in the daytime in the laser treated eyes is significantly greater than the variation in the normotensive eyes. This shows that in order to detect statistical differences between IOP variations induced by an IOP‐reducing drug, and the exaggerated spontaneous IOP variations present in the laser‐induced hypertensive eye, sufficient animals should be included in any study. Understanding the time‐specific IOP variation present in a group of monkeys with laser‐induced ocular hypertension is essential prior to using the model for the evaluation of IOP‐reducing drugs.     

Pharmacokinetics and pharmacodynamics of alfaxalone after a single intramuscular or intravascular injection in mallard ducks (Anas platyrhynchos)

Pharmacokinetics and pharmacodynamics of alfaxalone was performed in mallard ducks (Anas platyrhynchos) after single bolus injections of 10 mg/kg administered intramuscularly (IM; n = 10) or intravenously (IV; n = 10), in a randomized cross‐over design with a washout period between doses. Mean (±SD) C_max following IM injection was 1.6 (±0.8) µg/ml with T_max at 15.0 (±10.5) min. Area under the curve (AUC) was 84.66 and 104.58 min*mg/ml following IV and IM administration, respectively. Volume of distribution (V_D) after IV dose was 3.0 L/kg. The mean plasma clearance after 10 mg/kg IV was 139.5 (±67.9) ml min^?1 kg^?1. Elimination half‐lives (mean [±SD]) were 15.0 and 16.1 (±3.0) min following IV and IM administration, respectively. Mean bioavailability at 10 mg/kg IM was 108.6%. None of the ducks achieved a sufficient anesthetic depth for invasive procedures, such as surgery, to be performed. Heart and respiratory rates measured after administration remained stable, but many ducks were hyperexcitable during recovery. Based on sedation levels and duration, alfaxalone administered at dosages of 10 mg/kg IV or IM in mallard ducks does not induce clinically acceptable anesthesia.     

Progressive changes in ophthalmic blood velocities in Beagles with primary open angle glaucoma

Objective To measure changes in the ocular and orbital blood flow velocities by color Doppler imaging (CDI) in beagles with primary open angle glaucoma as the disease progressed from early to advanced stages. Methods CDI measurements were performed periodically on 13 glaucomatous Beagles during the nontreated mild, moderate and advanced stages of POAG over the course of 4 years. CDI was performed with the dogs lightly anesthetized (butorphanol 0.1 mg/kg IV, acepromazine maleate 0.02 mg/kg IV, and atropine sulfate 0.05 mg/kg) while the CD transducer was placed directly on the cornea anesthetized with 0.5% tetracaine hydrochloride. Intraocular pressure (IOP) by pneumatonography or TonoPen XL, heart rate and mean arterial blood pressure were measured at the beginning, middle and end of each study. The ophthalmic vessels examined included: external ophthalmic arteries and veins, long and short posterior ciliary arteries, anterior ciliary arteries and veins, primary retinal arteries, and vortex veins. Recordings of each vessel included peak systolic velocity (PSV), end diastolic velocity (EDV) and time averaged velocity (TAV), and when possible the resistive index (RI) and pulsatility index (PI) were computed. Results CDI abnormalities were present before intraocular pressure exceeded the normal range. As the animals aged, and the glaucoma progressed with higher levels of IOP, significant changes occurred in nearly all vessels, and generally included a major increase in RI (P < 0.001) and an increase in the PI (P < 0.001). Mean arterial blood pressure (105 ± 18 mmHg) and heart rate (118 ± 33/min) remained reasonably constant. The IOP gradually increased as the disease progressed (early and normotensive: 19.4 ± 3.9 mmHg; moderate: 29.7 ± 2 mmHg; and advanced: 44.5 ± 6 mmHg). The ocular veins seemed most influenced early on in the disease. Late in the disease, ocular venous blood flow could not be consistently demonstrated. An increase in the PI of ocular veins occurred in the moderately and severely affected glaucomatous Beagles. As the IOP increased, there were trends of increasing resistive index and pulsatility index in most arteries, and periods of marked decreased velocities of the vortex and external ophthalmic veins in severe cases. Conclusion CDI measurements in Beagles with primary open angle glaucoma during the course of 4 years indicate easily measurable and repeatable progressive blood flow abnormalities before the elevation of IOP and, thereafter, with gradually increased levels of IOP.     

Ophthalmic examination findings in adult pygmy goats (Capra hicus)

Objective To document normal ophthalmic findings and ocular abnormalities in captive adult pygmy goats. Animals studied Ten healthy adult pygmy goats (five male, five female; 5–11 years of age; 26–45 kg body mass) underwent complete ophthalmic examinations. Procedure Direct illumination, diffuse and slit‐beam biomicroscopy, indirect ophthalmoscopy, IOP measurements and Schirmer tear tests were performed. TonoVet^® rebound tonometry, followed by topical application of 0.5% ophthalmic proparacaine, and Tono‐Pen XL^® applanation tonometry were performed in each eye to obtain estimates of IOP. Results Ophthalmic abnormalities included corneal scars and pigmentation, incipient cataracts, lenticular sclerosis, and vitreal veiling. Mean STT values were 15.8 mm/min, with a range of 10–30 mm/min. Mean IOP values were 11.8 mmHg for TonoVet^®‐D, with a range of 9–14 mmHg; 7.9 mmHg for TonoVet^®‐P, with a range of 6–12 mmHg; and 10.8 mmHg for Tono‐Pen XL^®, with a range of 8–14 mmHg. Conclusions Ophthalmic examination findings in adult pygmy goats, including normal means and ranges for STT and IOP measurements, using applanation and rebound tonometry, are provided.     

Cardiopulmonary and anesthetic effects of the combination of butorphanol,midazolam and alfaxalone in Beagle dogs

ObjectiveTo evaluate the physiological variables, arterial blood gas values, induction of anesthesia quality, and recovery quality using the combination of butorphanol, midazolam and alfaxalone in dogs.AnimalsTen healthy adult Beagle dogs weighing 8.3 ± 3.1 kg.MethodsRectal temperature (T), pulse rate (PR), respiratory rate (f_R), mean arterial pressure (MAP), and arterial blood gases were measured and recorded prior to intravenous (IV) administration of butorphanol, prior to administration of both midazolam and alfaxalone IV 10 minutes later, then every 5 minutes for 20 minutes. M-mode echocardiographic left ventricular (LV) indices were measured before and 5 minutes after administration of alfaxalone. Qualitative scores for induction of anesthesia and recovery were allocated, duration of anesthesia and recovery were calculated, and adverse events were recorded.ResultsScores for induction and recovery quality were excellent. No significant adverse events were observed. Mean ± SD time from induction to extubation and to standing (full recovery) was 29 ± 6 and 36 ± 8 minutes, respectively. There were statistically significant changes in PR, f_R and MAP after drug administration. Transient hypercarbia developed after alfaxalone injection. The echocardiographic LV indices were reduced after alfaxalone injection, although those changes were not statistically significant.Conclusions and clinical relevanceThe combination of butorphanol, midazolam and alfaxalone provided excellent quality of induction of anesthesia and exerted minimal cardiopulmonary effects in healthy dogs.     

Comparison of a rebound and an applanation tonometer for measuring intraocular pressure in normal rabbits

Objective To compare intraocular pressure (IOP) measurements made on healthy adult rabbits without the effect of tranquilizers using the new applanation tonometer, Tono‐Pen Avia^®, and the rebound tonometer Tonovet^®. Methods Intraocular pressure was measured throughout the day (6:00, 9:00, 12:00, 15:00, and 18:00 h) in 38 adult New Zealand White rabbits (76 eyes). The animals were 20 males and 18 females, with a mean weight of 3.5 kg and an average age of 6 months. A complete ocular exam (including Schirmer tear test, fluorescein staining, slit‐lamp biomicroscopy, and direct ophthalmoscopy) was performed on all animals at the beginning of the trial. Rebound tonometry was performed, and after 10 min, anesthetic drops were instilled and applanation tonometry was carried out. IOP values obtained using the two techniques were analyzed statistically. Results The mean IOP was 9.51 ± 2.62 mmHg with Tonovet^®, and 15.44 ± 2.16 mmHg with the Tono‐Pen Avia^®. Significant differences between measurements with the two tonometers were observed (P < 0.001). The linear regression equation describing the relationship between the two tonometers was y = 0.4923x + 10.754 (y = Tonovet^® and x = Tono‐Pen Avia^®). High IOPs were recorded in the early measurements (6:00), but the average IOPs from both devices were statistically similar throughout the day (P = 0.086). The correlation coefficient was r² = 0.357. No significant difference in IOP regarding gender was observed. Conclusion The Tono‐Pen Avia^® recorded higher levels of IOP compared with the Tonovet^®. Early in the day, the IOP of rabbits was higher than later in the day, regardless of the tonometer used.