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Objective Animals Studied Procedures Results Conclusions To evaluate the effects of topical application of 0.5% tropicamide and 1% atropine on pupil diameter (PD), intraocular pressure (IOP), and tear production (TP) in healthy pet rabbits.Ten healthy client‐owned rabbits.A prospective, randomized, blinded, crossover study was conducted. Each animal received one drop of 0.5% tropicamide or 1% atropine in a randomly selected eye. PD, IOP, and TP were evaluated before drug instillation and at 0.25 h, 0.5 h, 0.75 h, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 24 h, 36 h, 48 h, 60 h, and 72 h post‐instillation. Data were analyzed using a paired two‐sample repeated measures T‐test with Bonferroni correction.In both tropicamide and atropine treated eyes, the mean PD significantly increased from 15 min until 12 h after treatment with a maximum PD at 45 min (+2.7 mm and + 2.4 mm respectively). Following tropicamide and atropine instillation, IOP increased significantly in treated eyes at 45 min (+2.9 mmHg) and 15 min (+5.2 mmHg) respectively, compared to untreated eyes. No significant effects were found on TP, in both tropicamide and atropine treated eyes at any time. No effects were observed in the untreated eyes on any of the parameters evaluated for both drugs.Topical treatment with 0.5% tropicamide and 1% atropine induced mydriasis in healthy pet rabbits and could be considered as effective options when mydriatic/cycloplegic drugs are required. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effect of intranasal (IN) and intramuscular (IM) administration of butorphanol and zolazepam‐tiletamine (ZT) combination on intraocular pressure (IOP) and tear secretion (TS) in rabbits. Fourteen healthy male New Zealand White rabbits weighing 3.05 ± 0.72 kg, aged between 1 and 2 years old, were included in the study. Animals randomly received 0.5 mg/kg butorphanol and 15 mg/kg ZT combination either with IN or IM administration. IOP and TS were measured at baseline (T0), and followed by 5, 15, 30, 45, and 60 min after drug administration. The sedation variables, the time to onset of sedation, duration of sedation, and sedation scores were also recorded. The route of administration for the butorphanol and ZT combination had no significant effect on the mean IOP (p =.301) and TS (p =.445). Furthermore, there were no significant changes observed in the IOP (p =.472) and TS (p =.348) over time. The time to onset of sedation was earlier in the IN group (4.57 ± 0.79 min) than in the IM group (5.86 ± 0.9 min; p =.0004). The duration of sedation was significantly longer for IM (57.43 ± 3.41 min) compared with IN (45.0 ± 1.91 min; p <.0001). No significant difference in the sedation score was observed between groups at all time points. In conclusion, both IN and IM administration of the butorphanol and ZT combination in rabbits had similar effects on IOP and TS. [ABSTRACT FROM AUTHOR]

Purpose: Ophthalmic diagnosis in many avian species remains hindered by a lack of normative values. This study aimed to establish normal ophthalmic parameters for select diagnostic tests in clinically normal Quaker parrots. Methods: Ninety‐six captive Quaker parrots aged 8–18 years underwent ophthalmic examination to include assessment of neuro‐ophthalmic reflexes, phenol red thread test, rebound tonometry, fluorescein staining, palpebral fissure length measurements, slit lamp biomicroscopy, indirect ophthalmoscopy, and ocular ultrasound biometry. Results: Menace response, dazzle reflex, and direct pupillary light reflex were present for all Quaker parrots. Tear production (mean ± SD) was 13.3 ± 4.0 mm/15 s and intraocular pressure (IOP, mean ± SD) was 10.6 ± 1.4 and 6.0 ± 1.3 mmHg in the D and P rebound tonometer calibration settings, respectively. For IOP measurement, D and P calibration settings were not interchangeable, with the lesser variation of the D setting preferred in the absence of a gold standard. Ultrasound measurement of the anterior chamber depth increased with age and males had longer axial globe and vitreous lengths. Incidental adnexal and ocular lesions, identified in 36/96 (37.5%) of Quaker parrots, did not statistically affect the created reference data. Conclusions: This work provides reference values and clinical findings to assist with monitoring the health of wild populations and maintaining the health of captive Quaker parrots. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the relationship between lacrimation and age in a homogeneous group of healthy beagle dogs during the first year of life. Materials and methods: Schirmer tear test I (STT I) was performed at an interval of 12–15 days in both eyes of 16 clinically healthy beagle dogs (eight males and eight females) from 94 to 361 days of age. Three different quadratic polynomial regression equations were estimated for the variation in lacrimation: (1) for the entire period (19 observations), (2) for observations 1–4 (days 94–136), and (3) for observations 5–19 (days 150–361). Results: By fitting quadratic regression equations to different phases of tear production during the dog's first year of life, it was possible to see that with each day of life, lacrimation increased 0.08 times (8%). From days 94 to 136, however, lacrimal production fell 1.1 times with each day of life. From day 150 to 361, production increased by 0.02 (2%) each day of life. In addition, there was a positive significant and moderate linear correlation between body weight and STT I values (p =.01). Conclusion: In dogs, during the first year of life, STT I data distribution is parabolic in shape. Age significantly affected tear production. STT I decreased at approximately 108–121 days of age and increased thereafter. Body weight was a significant factor for STT I in young dogs. The establishment of this normal pattern of lacrimation is important for both clinical practitioners and laboratory studies. [ABSTRACT FROM AUTHOR]

Objective: To describe normative ocular surface and aqueous tear testing data for cats of various cephalic conformation. Animals studied: Fifty‐three healthy adult cats (11 British Shorthair, 11 Burmese, 10 Devon Rex, 10 Scottish Fold, and 11 Sphynx). Procedures: Blink rate, corneal tactile sensation (CTS), and Schirmer tear test with or without topical anesthesia (STT‐1, STT‐2) and with nasolacrimal stimulation (NL‐STT1, NL‐STT2) were assessed. Palpebral fissure length (PFL) and skull morphology were measured, and cephalic index (CI) and craniofacial ratio (CFR) calculated. Results: Mean ± SD test results were as follows: blink rate (5.0 ± 2.3 blinks/min), CTS (3.2 ± 0.7 cm), STT‐1 (11.2 ± 4.3 mm/min), STT‐2 (6.7 ± 3.6 mm/min), NL‐STT1 (13.4 ± 5.7 mm/min), NL‐STT2 (13.5 ± 5.2 mm/min), and PFL (2.0 ± 0.2 cm). Corneal sensitivity did not differ significantly among breeds (p =.152) but was negatively correlated with body weight (r = −.32, p =.019). STT‐1 significantly differed among breeds (p <.001) and was lowest in Sphynx cats (8.7 ± 4.3 mm/min). A positive correlation was detected between STT‐1 values at 30 and 60 s (r =.98; p <.001). The nasolacrimal reflex significantly increased STT in anesthetized and unanesthetized eyes (approximately +100% and +20%, respectively; p ≤.002). STT‐1 tended to be higher in intact versus neutered cats (p =.062). Age did not impact any test result (p ≥.085). Conclusions: Normative data described here serve as a baseline for future studies assessing ocular surface disease in multiple feline breeds. Unlike dogs, brachycephalic cats did not have lower CTS or STT‐1 than non‐brachycephalic cats. [ABSTRACT FROM AUTHOR]

Objective: To characterize the ocular surface parameters and determine the prevalence of ocular pathology in Shih Tzu dogs. Animal Studied: Fifty Shih Tzu dogs (28 male, 22 female). Procedures: Each dog underwent a complete ophthalmic examination (recording any pathology) and a series of diagnostics, allowing for a 10 min‐interval between tests: intraocular pressure (IOP), blink rate, palpebral fissure length (PFL), corneal tactile sensation (CTS), Schirmer tear test and nasolacrimal reflex without (STT‐1, NL‐STT1) and with topical anesthesia (STT‐2, NL‐STT2), tear ferning, strip meniscometry test (SMT), tear film breakup time (TFBUT), and punctate fluorescein staining (PFS) of the cornea. Results: Mean ± SD test values were as follows: IOP (17.9 ± 3.7 mmHg), blink rate (2.4 ± 1.4 blinks/min), PFL (23.8 ± 1.8 mm), CTS (1.8 ± 0.7 cm), STT‐1 (22.0 ± 5.5 mm/min), NL‐STT1 (24.2 ± 4.7 mm/min), STT‐2 (16.9 ± 6.5 mm/min), NL‐STT2 (18.5 ± 7.5 mm/min), SMT (7.5 ± 3.5 mm/5 s), TFBUT (5.3 ± 2.4 s), tear ferning (1.3 ± 0.7), and PFS (1.6 ± 0.6). PFL was significantly greater in male vs. female Shih Tzus (p<.001). Age was negatively correlated with TFBUT results (r = −0.31, p =.027). Lagophthalmos was observed in 82% eyes. Ocular surface pathology was common, including adnexal abnormalities (100% eyes with caruncular trichiasis and medial lower lid entropion) and corneal opacification (27% pigmentation, 20% fibrosis, 12% neovascularization). Conclusions: Qualitative tear film deficiency (low TFBUT), along with several anatomical abnormalities that promote ocular irritation and reduce globe protection, together help explain the concerningly high prevalence of ocular surface disease in the Shih Tzu breed. Prophylactic measures (e.g., medial canthoplasty, topical lubrication) could be considered to improve ocular health in Shih Tzus. [ABSTRACT FROM AUTHOR]

Objective: The objective of the present study was to examine the effect of different light intensities on tear production, corneal thickness, and intraocular pressure in broilers. Animals studied: Both eyes of 72 male broilers were evaluated in this study. Materials and Methods: Broilers were divided into the following three groups: low light intensity (n = 24, 5 lux), moderate light intensity (n = 24, 20 lux), and high light intensity (n = 24, 80 lux). The eyes of all birds (n = 72) underwent a complete ophthalmic examination, which included the Schirmer tear test (STT‐I), intraocular pressure (IOP), and the central cornea thickness measurement (CCT). The effect of light intensity on the Schirmer test, intraocular pressure, and central corneal thickness values was examined at eye and animal level (right and left eyes separately and cumulatively/no distinguishing left or right) by using one‐way ANOVA. Results: At the animal level, without discrimination of left and right eye measurements, statistically significant differences were found between 5–20 and 20–80 lux groups on IOP measurements (p <.05). The difference in CCT measurements between the 5 and 20 lux groups was statistically significant (p <.05), and the corneal thickness of the 5 lux group animals was found to be statistically significant and higher than the 20 lux group (p <.05). Conclusions: In conclusion, light intensity has an influence on eye health in broilers. Present results may attribute to the future studies as a reference value for broilers raised under different light intensities. [ABSTRACT FROM AUTHOR]

Objective: Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT‐1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). Animal studied: Six healthy mares. Procedures: In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day for 1 day, and then once a day for 2 days, as commonly used in practice. Daily and two days after the last topical drug administration, HR, digestive auscultation, feces production, STT‐1, IOP, and PD were recorded. Results: The cyclopentolate alone significantly increased the horizontal and vertical PD of the treated eye from day 2 to day 6 (p <.0001) compared with the baseline value. The combination with topical phenylephrine did not have any additional effect on mydriasis compare with the cyclopentolate alone. The other ocular and digestive parameters were not affected by repeated doses of cyclopentolate alone or combined. Conclusions: Repeated administration of cyclopentolate alone or combined with phenylephrine induce a significant mydriasis for at least 48 h after the last administration in normal horses' eyes, and do not affect STT‐1, IOP, digestive function, and HR. The phenylephrine combined with the cyclopentolate did not potentiate the pupil dilation when compared with cyclopentolate alone in healthy horses. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of acute conjunctivitis on tear film characteristics and corneal sensitivity in dogs. Animals studied: Eight female spayed Beagle dogs (1.5‐2 years old, 7.5‐10 kg). Procedures: On two consecutive days, one randomly selected eye in each dog received 1 or 375 mg/mL histamine solution to induce mild or severe conjunctivitis, while the contralateral eye served as control. Diagnostic tests were performed in the following order: fluorescein instillation and repeated tear collection over 20 minutes (to determine tear volume [TV] and turnover rate [TTR] by fluorophotometry), Schirmer tear test‐1 (STT‐1), tear ferning, corneal esthesiometry, and tear film breakup time (TFBUT). Results: Results are presented as median values for severe conjunctivitis, mild conjunctivitis, and control eyes. Eyes with severe conjunctivitis had significantly higher STT‐1 (24, 19.5, 17.5 mm/min; P =.002) and significantly lower TFBUT (10.5, 13.5, 15.5 s; P =.002), but no changes were noted in corneal tactile sensation (2, 2.5, 2.5 cm) or tear ferning (grades 2, 2, 2.5). Severe conjunctivitis significantly increased TV by nearly 10‐fold (631, 97, 65 µL) initially (reflex tearing), although basal TV returned rapidly (<5 minutes) in all eyes (46, 58, 48 µL). Finally, there was a nonsignificant trend for higher reflex TTR in the conjunctivitis vs control eyes (68, 58, 43%/min). Conclusions: Experimentally induced conjunctivitis increases tear quantity and decreases tear quality in dogs, but has no impact on corneal sensitivity. Changes in tear film dynamics could affect ocular pharmacology (eg, precorneal retention time), although homeostasis of lacrimal volume and drainage is rapidly restored. [ABSTRACT FROM AUTHOR]

Objectives: To document ophthalmic findings, Schirmer's tear test I (STT), and intraocular pressure (IOP) values for anesthetized chimpanzees (Pan troglodytes). Animals Studied: Ten captive chimpanzees from Zoo Knoxville and Chattanooga Zoo. Procedures: Ten chimpanzees were anesthetized for annual physical examinations, blood collection, and ophthalmic examination. Each was anesthetized with intramuscular (IM) injections of dexmedetomidine, midazolam, and ketamine. Ophthalmic findings and STT and IOP values in addition to general health information were recorded for each chimpanzee. Pupillary diameter was measured after topical tropicamide administration. A Shapiro‐Wilk test of normality was done for age, weight, STT values, IOP values, and pupil size. Results: Ages ranged from 11 to 42 years. Weight range was 40.9‐83.6 kg. The mean STT was 13.4 ± 5.3 mm/min. The mean IOP was 14 ± 4.2 mm Hg. Seven of the 10 chimpanzees were considered geriatric, and each had perilimbal lipid deposits. Sedative‐associated miosis was successfully counteracted with a regimen of repeated applications of tropicamide, enabling complete fundic examination. Conclusions: A complete ophthalmic examination can be done on anesthetized chimpanzees with the protocol used in this study. [ABSTRACT FROM AUTHOR]

Objective: To characterize diagnostic findings, test-retest repeatability, and correlations among lacrimal tests in dogs of diverse cephalic conformations. Animal studied: Fifty healthy dogs (25 brachycephalic, 25 nonbrachycephalic). Procedures: A series of diagnostics were performed in each dog, allowing for a 10-minute interval between tests and repeating each test 24 hours later under similar conditions: corneal tactile sensation (CTS), strip meniscometry test (SMT), phenol red thread test (PRTT), endodontic absorbent paper point tear test (EAPPTT), Schirmer tear test-1 without (STT-1) or with nasolacrimal stimulation (NL-STT1), and Schirmer tear test-2 (STT-2). Results: Mean ± SD test values were lower in brachycephalic vs. nonbrachycephalic dogs (except for SMT; 7.4 ± 2.0 mm/5 seconds vs 7.3 ± 2.4 mm/5 seconds), with statistically significant differences noted for CTS (1.8 ± 0.5 cm vs 3.4 ± 0.8 cm), PRTT (37.2 ± 4.0 mm/15 seconds vs 41.1 ± 5.5 mm/15 seconds), STT-1 (20.1 ± 3.4 mm/min vs 23.3 ± 5.7 mm/min), STT-2 (13.0 ± 3.4 mm/min vs 16.9 ± 3.9 mm/min), and NL-STT1 (23.2 ± 3.6 mm/min vs 27.1 ± 5.4 mm/min), and nonsignificant differences for EAPPTT (16.6 ± 2.7 mm/15 seconds vs 17.5 ± 2.9 mm/15 seconds). Nasolacrimal stimulation increased STT-1 values by 18% on average. Correlations among tests were generally weak to moderate (r < .70) except for a strong correlation between STT-1 and NL-STT1 (r = .83, P < .001). Test reliability was good although test-retest repeatability was generally poor to moderate, as depicted by low intraclass correlation coefficients (ICC = 0.75) and wide 95% limits of agreement, except for CTS (ICC = 0.91). Conclusions: Corneal sensitivity and aqueous tear secretion are lower in brachycephalic dogs. A comprehensive assessment of the ocular surface requires the combination of several diagnostic tests. The nasolacrimal reflex may provide a useful diagnostic and therapeutic tool in dogs. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the tear production, intraocular pressure, and central corneal thickness in healthy white‐tailed deer (Odocoileus virginianus) and assess for seasonal variability. Animals studied: Nineteen healthy fawns (3‐10 days old) and 8 healthy adult white‐tailed deer (164‐280 days old) were studied. Procedures: All fawns were manually restrained for the study, while adult animals were immobilized with an intramuscular injection of combined xylazine (2.2 mg/kg), tiletamine (1 mg/kg), and zolazepam (1 mg/kg). Tear production (STT‐1) was evaluated in both eyes of all fawns. Intraocular pressure (applanation and rebound tonometry) and central corneal thickness (ultrasound pachymetry) were determined in both eyes of all fawns and adult deer. Results: Mean ± SD tear production in fawns was 12.32 ± 4.46 mm/min. Mean ± SD IOP values in the fawns were 16.21 ± 4.97 mm Hg (TonoPen®) and 14.05 ± 5.03 mm Hg (TonoVet®). In adult deer, mean ± SD IOP values were 15.57 ± 2.88 mm Hg with TonoPen® and 12.87 ± 2.57 with TonoVet®, and TonoPen® significantly overestimated the IOP, compared to TonoVet® (P < 0.005). The IOP was not significantly different between young and adult animals (P = 0.22). A significant difference (P < 0.005) in CCT values was observed between fawns (528.42 ± 27.65 μm) and adult deer (747.55 ± 41.60 μm). Conclusions: This study reports normal values of tear production in healthy fawns, and intraocular pressure and central corneal thickness in healthy young and adult white‐tailed deer. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to determine if a circadian rhythm exists in Schirmer's tear test (STT‐1) values in a group of healthy adult cats. Animals studied: Twenty adult neutered Domestic Short‐haired cats (DSH) were used in the study. Procedures: Tear production was measured with the Schirmer tear test (STT‐1) at 12 different time points over a 48‐hour period. Results: A significant difference (approximately 4.3 mm/min) was noted between STT‐1 values measured between 4 pm (lowest) and 12 am (highest) on both day 1 (P = 0.02) and day 2 (P = 0.01), and substantial variation in STT‐1 values was observed at different times during the 48‐hour period. Conclusions: Significant variation in mean STT‐1 values demonstrates that there is a circadian rhythm in tear production in cats and thus shows the importance of taking the time of day into account when measuring STT‐1 in cats. [ABSTRACT FROM AUTHOR]

Objectives The purpose of this study was to establish a reference value of tear production and intraocular pressure in clinically normal ducks and geese. Animal Studied The study population consisted of forty-eight ducks (24 males and 24 females) and fifty-two geese (26 males and 26 females). Procedures Birds were gently physically restrained in dorsoventral position without any pressure to the head and neck. Tear secretion and intraocular pressure were measured using 5-mm-wide Schirmer tear test strips and TonoVet® rebound tonometer, respectively. Results Overall mean ± 2 SD STT and IOP values of all eyes were 6.2 ± 2.2 mm/min and 10.2 ± 2.2 mmHg, respectively, for the ducks; 5.5 ± 2.6 mm/min and 9.1 ± 2.0 mmHg, respectively, for the geese. There was no statistically significant difference in IOP between left eye and right eye or between males and females in ducks ( P = 0.56, P = 0.63) and geese ( P = 0.23, P = 0.22). Analysis of variance revealed that there were no significant differences in the STT and IOP between the breeds in ducks ( P = 0.49, P = 0.68) and geese ( P = 0.14, P = 0.26). Conclusions Results of this study may be beneficial for the diagnosis and therapeutic monitoring of ducks and geese affected with Keratoconjunctivitis sicca, glaucoma, and uveitis. [ABSTRACT FROM AUTHOR]

Objective To determine the effects of short-term oral administration of trimethoprim-sulfamethoxazole on tear production in clinically normal guinea pigs. Animal studied Thirty-two healthy adult Abyssinian guinea pigs were used in this study. Procedure One day before the start of the trial, the pretreatment baseline phenol red thread test ( PRTT) values were recorded. Sixteen guinea pigs in the treated group received 25 mg/kg trimethoprim-sulfamethoxazole orally twice a day for 14 days. The other sixteen guinea pigs were used as untreated controls and received a placebo during the study. All the ophthalmic tests were performed without chemical restraint. PRTT values were evaluated in both eyes of all the guinea pigs using a commercial PRTT strip of a single lot number on days 0 (baseline), 15, and 21 after starting the trial. Results The pretreatment baseline mean ± SD PRTT values for the treatment and control groups were 11.12 ± 3.82 mm/15 s and 11.93 ± 2.73 mm/15 s, respectively. After 14 days of drug administration, the mean ± SD PRTT values for the treatment and control groups were 10.87 ± 3.11 mm/15 s and 13.00 ± 2.47 mm/15 s, respectively. On Day 21, the mean ± SD PRTT values for the treatment and control groups were 12.62 ± 4.05 mm/15 s and 12.87 ± 2.99 mm/15 s, respectively. Significant decreases in the PRTT values, compared with the pretreatment baseline values, were not observed in the treatment group on Day 15 ( P = 0.14) and Day 21 ( P = 0.31). Conclusions Trimethoprim-sulfamethoxazole did not decrease tear production in the guinea pigs in this study. [ABSTRACT FROM AUTHOR]

Objective To describe Schirmer tear test I and rebound tonometry findings in healthy bovine calves. Animals studied Thirty-three clinically normal dairy breed calves of mean ( SD) 11 (1.1) weeks (range, 9.3-13.3 weeks) of age were evaluated. Procedures A Schirmer tear test I was performed on each eye followed by tonometry, using a TonoVet® without topical anesthesia. We report means ( SD) and statistical analysis of data for each assay. Results For both Schirmer tear test ( STT) I and tonometry, significant differences were not found between fellow eyes ( P = 0.1536 and P = 0.83, respectively). The mean ( SD) STT I value of all eyes was 20.4 (5.0) mm/min (range, 9-34 mm/min) while the mean ( SD) intraocular pressure ( IOP) value of all eyes was 15.2 (5.2) mmHg (range, 7-25 mmHg). Conclusions This study reports normal data for the STT I and rebound tonometry in calves. This data may be useful in complete ophthalmic examinations of cattle, guiding diagnosis of glaucoma, uveitis, and keratoconjunctivitis sicca. However, results of these diagnostic modalities must be interpreted in light of clinical signs, given the wide range of normal values obtained in this study. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To determine the normal reference range for Schirmer tear test‐1 (STT‐1) values in eyes of healthy alpacas (Vicugña pacos). Methods: Complete ophthalmic examinations were performed on forty healthy alpacas (80 eyes). STT‐1 values were obtained in both eyes of all alpacas using a commercial STT strip of a single lot number. Data were analyzed, using a doubly repeated measures ANOVA design, Student's paired t‐test, and Pearson correlation test, with P ≤ 0.05 considered significant. Results: The STT‐1 values ± standard deviation (SD) were 20.80 ± 4.01 mm/min OD, 20.00 ± 4.13 mm/min OS, and 20.88 ± 4.04 mm/min OU (range 15.50–30.50 mm/min). No significant differences in STT‐1 were found between OD and OS. STT‐1 was not significantly affected by breed. Schirmer tear test‐1 values were significantly increased by 3.45 mm/min for every 10 year increase in age. Conclusions: This study provides a reference range of STT‐1 in the healthy alpaca which can assist veterinarians in diagnosing potential keratoconjunctivitis sicca, tear film abnormalities, as well as ocular surface diseases in alpacas. [ABSTRACT FROM AUTHOR]

Objective To evaluate endodontic paper point tear test ( PPTT) in rabbits and compare changes in corneal touch threshold ( CTT) induced by Schirmer tear test ( STT) and PPTT. Normal corneal sensitivity recovery time after both tear tests was also measured. Also, mean PPTT and STT values were obtained. Methods Tear production of 20 eyes, from 10 rabbits, was evaluated using STT and the PPTT. Central corneal touch threshold was measured by a Cochet-Bonnet esthesiometer before any tear test was performed (zero time), immediately after the test (1 min), and consecutively at 6, 11, 16, and 26 min. Tests were conducted on three consecutive days: Day 1 - control condition, no tear tests performed only the CTT; Day 2 - CTT before and after PPTT; and Day 3 - CTT before and after STT. CTT values were compared using repeated measures ANOVA. Results Corneal touch threshold was significantly increased for at least 16 min after STT, indicating STT causes corneal discomfort. No difference was found between CTT following PPTT and controls, indicating PPTT caused minimal corneal discomfort. The mean (± SD) value for STT was 5.2 ± 1.0 mm/min and for PPTT was 13.8 ± 1.5 mm/min. Discussion The aqueous fraction of rabbit's tears can be successfully measured by PPTT. This report established reference values for PPTT in rabbits. Additionally, the absence of a significant difference in CTT after PPTT compared with controls shows that PPTT is well tolerated by rabbits. Considering the improved comfort (compared with STT), accuracy, and low cost, PPTT is a bona fide method of measuring aqueous tear production in rabbits. [ABSTRACT FROM AUTHOR]

Objective To determine the effect of topical naltrexone 0.3% on tear production, corneal sensitivity, and tear film stability in normal brachycephalic dogs. Animals Studied Twenty-two normal brachycephalic dogs. Procedures Measurements of tear production (Schirmer tear test I and II), intraocular pressure ( IOP), central corneal sensitivity ( CS), and tear film breakup time ( TFBUT) were collected at time 0, 1, and 24 h after administration of either naltrexone ( NTX) 0.3% or placebo ( SV). Naltrexone or SV was then administered once daily for 1 week, and the above measurements were repeated at 7 days, then again 7 days after discontinuing medication. Owners scored the degree of comfort, redness, rubbing, squinting, and tearing. Serum was collected at time 0, 1, 24 h, and 7 days to determine systemic concentrations. Results Owners reported no significant change in the degree of comfort, redness, rubbing, squinting, or tearing. Naltrexone was detected in serum of all treated dogs 1-h postadministration (average: 908 pg/mL, range: 319-1570 pg/mL) and in two dogs at the 1-week time point. Naltrexone was not detected at the 24-h time point. There was no significant effect of NTX on STT1, STT2, IOP, CS, or TFBUT. Conclusions Naltrexone 0.3% is well tolerated and safe when applied topically to the eye once daily. Naltrexone 0.3% did not show any significant effects on corneal parameters as measured in this study. At once, daily dosing NTX is systemically absorbed; however, the degree of systemic absorption is not likely to be clinically significant. [ABSTRACT FROM AUTHOR]

Objective To determine the normal reference range for phenol red thread test ( PRTT) values in clinically normal Syrian hamsters ( Mesocricetus auratus). Animals Sixteen healthy adult Syrian hamsters (eight males and eight females) were used in this study. Procedure Ophthalmic examinations were performed without chemical restraint. PRTT values were evaluated in both eyes of all Syrian hamsters using a commercial PRTT strip of a single lot number. Results No statistically significant differences between right and left eyes were found for any of the results. The mean ± SD PRTT values for the study population were 6.8 ± 2.5 mm/15 s with a range from 3 to 11.5 mm/15 s. Mean PRTTs in male animals were 5.1 ± 1.2 mm/15 s, whereas mean PRTTs in female hamsters were 8.5 ± 2.3 mm/15 s. Comparison between mean PRTT values in males and females showed a significant difference ( P = 0.004). Mean weights for males and females were 80.9 ± 4.8 and 90.6 ± 8.5 g, respectively. No linear relationship between mean PRTT and body weight was found in female ( P = 0.46) and male ( P = 0.92) hamsters. Conclusion This study provides novel data for normal reference ranges of PRTT values in healthy Syrian hamsters. Results of this study may assist veterinarians in the diagnosis of ocular surface disease and syndromes affecting the tear film in these species. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

Objective To establish a baseline range or average for tear production in normal juvenile dogs and evaluate the effects of age, weight, and gender on Schirmer tear test (STT) in juvenile dogs. Materials and methods Healthy puppies of various breeds <6 months of age. STT1 and STT2 were performed in both eyes of each subject. Statistical analysis was performed using a backwards stepwise regression model with repeated measures. Using continuous variables of STT1 and STT2 as the dependent variables separately, the independent variables were age (days), eye (left or right), gender (male or female), ocular disease processes in eyes or not, and weight (kg). Results Eighty-six eyes from 27 males and 16 females were included in this study. Ages ranged from 25 to 133 (mean ± SEM: 61.74 ± 24.15) days and weights ranged from 0.88 to 8.86 (3.27 ± 2.22) kg. STT1 results ranged from 0 to 26 (15.76 ± 5.79) mm/min. STT2 results ranged from 0 to 24 (8.79 ± 5.01) mm/min. Age, weight, and gender significantly affected STT1 results. Weight and gender significantly affected STT2 results. STT1 values increased by 0.15 mm/min for each 1 day increase in age and by 0.84 mm/min for each 1 kg increase in body weight. STT2 values increased by 0.57 mm/min for each 1 kg increase in body weight. Conclusions Age, weight, and gender significantly affect tear production in normal juvenile dogs. STT1 increases to adult values at approximately 9–10 weeks of age. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective To determine whether there is an association between evisceration with intraocular prosthesis placement via a dorsal scleral approach and decreased corneal sensitivity or aqueous tear production in dogs. Design Prospective study. Procedure Twenty-one dogs scheduled to undergo unilateral evisceration with intraocular prosthesis, and with a normal normotensive contralateral eye, based on slit-lamp biomicroscopy, indirect ophthalmoscopy and applanation tonometry, were included in the study. Central corneal sensitivity was measured with a Cochet-Bonnet esthesiometer prior to (week 0) and 2, 7, 14 and 28 weeks following surgery. Other pre- and postoperative data collected were Schirmer's tear test (STT I), Schirmer's tear test with topical anesthesia (STT II), corneal fluorescein retention, and intraocular pressure (IOP; postoperative control eye only). Axial globe length was determined for both eyes. Scleral incision length in the surgery eye was also recorded. Results Corneal sensitivity was significantly lower in eyes undergoing evisceration with intraocular prosthesis than in control eyes both preoperatively and postoperatively at all time points. There was no significant difference between preoperative and postoperative corneal sensitivity within the two groups. There was no significant difference in STT I or STT II-values between control eyes and surgery eyes preoperatively. There was a significant difference between preoperative and 2-week postoperative STT I in the surgery eye. There was a significant difference between the preoperative and 28-week postoperative STT II in the surgery eye. The 28-week postoperative STT I-values differed significantly between control and surgery eyes. Corneal sensitivity tended to decrease with increased degree of buphthalmos or with increased scleral incision length, although neither relationship was statistically significant. Conclusions Eyes that have sustained chronically elevated intraocular pressure had decreased axial corneal sensitivity compared to normal eyes, which persisted even after intraocular pressure was reduced. The presence of buphthalmos appeared to be a factor in globes developing decreased corneal sensitivity. Evisceration via a dorsal scleral incision did not result in a significant further reduction in axial corneal sensitivity. A mild reduction in aqueous tear production occurred over time in globes following evisceration with intraocular prosthesis. [ABSTRACT FROM AUTHOR]

Medetomidine is a commonly used sedative in veterinary medicine whether administered alone or in combination with an opioid such as butorphanol. There are no previous studies that look at the effects of this drug on sequential Schirmer tear test (STT) 1 readings in dogs, including effects on tear production after reversal of the drug. The present study looked at two groups of 10 dogs each that were sedated with intravenous medetomidine or a combination of medetomidine and butorphanol. All dogs had tear readings taken presedation, 15 min postsedation, and 15 min after reversal of medetomidine with atipamezole. Results revealed that intravenous sedation with medetomidine and medetomidine-butorphanol in dogs with no history of ophthalmic disease and presedation STT 1 readings above 15 mm/min, causes a significant decrease in tear production that is measurable at 15 min postsedation. Readings returned to near presedation values within 15 min postreversal in most cases. It is therefore recommended that all eyes be treated with a tear substitute from the time the sedative is given until at least 15 min after reversal. [ABSTRACT FROM AUTHOR]

To investigate the effect of 0.02% tacrolimus in aqueous suspension on tear production in dogs with keratoconjunctivitis sicca (KCS). One hundred five dogs diagnosed with KCS [Schirmer tear test (STT) ≤ 10 mm/min and clinical signs of dry eye]. Eyes with marginally decreased STT (11 ≤ 15 mm/min) and clinical signs of dry eye were also evaluated. The investigation was conducted in two parts: an initial efficacy study and a subsequent double blinded controlled study. In the efficacy study, the effect of topical tacrolimus (formerly FK-506) on tear production in dogs with primary KCS was evaluated. Dogs were divided into four categories: 1) 59 eyes (38 dogs) naïve to tear stimulation therapy with initial STT ≤ 10 mm/min; 2) 28 eyes (21 dogs) naïve to tear stimulation therapy with initial STT 11 ≤ 15 mm/min; 3) 30 eyes (15 dogs) maintained successfully on CsA therapy; 4) 47 eyes (24 dogs) unresponsive to CsA therapy. STT and clinical signs were evaluated prior to and after 6 to 8 weeks of twice daily tacrolimus administration. Tacrolimus was substituted for CsA therapy in categories 3 and 4. The controlled study compared the effect of topical tacrolimus in aqueous suspension to administration of the aqueous carrier alone on tear production in 20 dogs with primary KCS. In the efficacy study, STT increased by 5 mm/min in 84.7%, 25.0%, 26.7% and 51.1% of eyes in categories 1, 2, 3 and 4 respectively after tacrolimus administration. Eighty-three percent of eyes with extremely low initial STT (≤ 2 mm/min), increased 5 mm/min after tacrolimus. In the controlled study, STT increased by 5 mm/min in 7/10 dogs (14/20 eyes) that received tacrolimus and in none of the 10 dogs that received aqueous carrier alone. Dogs receiving just the aqueous carrier were subsequently treated with tacrolimus, and STT increased 5 mm/min in 9 dogs (18/20 eyes) after administration. Twice daily administration of 0.02% tacrolimus in aqueous suspension effectively increased tear production in dogs with KCS. Topical tacrolimus is a promising alternative to topical CsA for treatment of KCS and may be beneficial in patients with less than optimal response to topical CsA. [ABSTRACT FROM AUTHOR]

The objectives of this study were to observe the effects of trimethoprim–sulfadiazine on equine tear production and to determine normal fluctuations in Schirmer tear test (STT) values in horses. A randomized, placebo-controlled, blinded clinical trial measuring STT values in 15 horses over an 8-week period was performed. The treatment group (eight horses) received 30 mg/kg trimethoprim–sulfadiazine orally once a day and the control group (seven horses) received placebo (flour) at the same time. All horses were housed outdoors throughout the study. Schirmer tear test values were measured at 0, 2, 4, 6 and 8 weeks, and 4 weeks after discontinuation of treatment. There were no significant differences in tear production between the treated and control groups. Fluctuations in STT were observed and may result from individual and environmental variations. Trimethoprim–sulfadiazine did not decrease tear production in the horses in this study. Horses normally experience periodic fluctuations in STT values. [ABSTRACT FROM AUTHOR]

To evaluate the effect of a single dose of topical 1% tropicamide on tear production as measured by the Schirmer tear test (STT) in the normal dog and cat. Twenty-eight dogs and 32 cats received 50 µl : l of 1% tropicamide in one eye and the opposite eye served as the control. STTs were performed immediately before instillation of tropicamide and then at 1, 4, 8 and 24 h post drug instillation. STT results were compared between the control and treated eyes at the different times. Aqueous tear production in dogs, measured by STT, was not significantly reduced. The mean ± SEM STTs for the baseline time for control and tropicamide-treated eyes were 19.9 ± 0.8 and 20.3 ± 0.8 mm wetting/min, respectively. For the control eyes, the subsequent mean ± SEM STT levels were 20.3 ± 0.9 (1 h), 21.1 ± 0.8 (4 h), 20.1 ± 0.9 (8 h), and 18.7 ± 0.7 (24 h). For the tropicamide-treated eyes, the subsequent mean ± SEM STT levels were 19.4 ± 0.9 (1 h), 19.3 ± 0.9 (4 h), 20.0 ± 0.9 (8 h), and 18.4 ± 0.8 (24 h). Aqueous tear production of both eyes was significantly reduced in cats at 1 h but returned to baseline by 4 h post tropicamide instillation. The mean ± SEM STT levels for the baseline time in cats for control and tropicamide-treated eyes were 14.9 ± 0.8 and 14.7 ± 0.8 mm wetting/min, respectively. Subsequent mean ± SEM STT levels for the control eyes were 6.4 ± 1.1 (1 h), 11.9 ± 1.0 (4 h), 13.9 ± 0.8 (8 h), and 16.4 ± 1.0 (24 h). For the tropicamide-treated eyes, the subsequent mean ± SEM STT levels were 5.3 ± 0.8 (1 h), 10.2 ± 0.8 (4 h), 14.7 ± 1.0 (8 h), and 16.6 ± 1.0 (24 h). Single dose 1% tropicamide does not significantly lower tear production rates, as measured by the STT, in normal dogs. However, in normal cats single doses of 1% tropicamide in one eye cause significant reductions in tear production of both eyes at 1 h that recovered to baseline levels by 4 h. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of acepromazine or xylazine on Schirmer tear test 1 results in clinically normal cats. Animals Sixteen healthy cross-breed cats. Procedure The animals were randomly divided into two groups of eight cats each. The first group was sedated with acepromazine alone (0.2 mg/kg) and the second group received only xylazine (2 mg/kg). All cats had Schirmer tear test (STT) readings taken prior to sedation and at 15 and 25 min postsedation. Results Sedation with acepromazine or xylazine in cats with normal pre-sedation STT 1 values caused a statistically significant decrease in mean values of tear production in both groups. In acepromazine group the mean ± SEM STT at T15 and T25 were 4.31 ± 0.98 ( P < 0.001) and 5.18 ± 1.07 ( P = 0.002). The post-treatment mean ± SEM values in xylazine group were 2.18 ± 0.97 ( P < 0.001) and 2.62 ± 1.17 ( P = 0.001) at 15 and 25 min respectively. Comparison between T15 and T25 in acepromazine group ( P = 0.49) and xylazine group ( P = 0.56) revealed no significant differences. Conclusion These observations indicate that both acepromazine or xylazine significantly reduced tear production in clinically normal cats. In cats, clinicians should measure STT values prior to utilizing acepromazine or xylazine as sedatives in order to accurately assess the results. Moreover, sterile ocular lubricant or tear replacement should be used as a corneal protectant during sedation with these drugs. [ABSTRACT FROM AUTHOR]

Objective To observe the effect of topical 1% tropicamide on equine tear production as measured by Schirmer I tear test. Materials and methods Fourteen adult horses received one drop of 1% tropicamide ophthalmic solution in one eye and the opposite eye served as the control. The tear production in both eyes was tested at 1, 2, 4, 6, and 24 h after 1% tropicamide administration. Results Measurements made 1 h after treatment revealed a significant reduction in Schirmer tear test values in tropicamide treated eyes ( P = 0.002). The observed decrease in tear production was maintained up to 4 h after treatment ( P = 0.002). Although tropicamide-induced decrease in STT values was observed in the treated eyes, the contralateral eyes did not show significant changes in Schirmer tear test results. Conclusion Single dose of topical 1% tropicamide resulted in statistically significant reduction in Schirmer tear test values in clinically normal horses. [ABSTRACT FROM AUTHOR]