Background and Aim: Tonometers are an important instrument for measuring intraocular pressure (IOP) in the diagnosis of glaucoma or uveitis. This study aimed to compare the accuracy of the main types of tonometers with different IOP measurement methodologies in dogs: TonoVet and TonoVet Plus (rebound), Tono-Pen Avia Vet (applanation), and Kowa HA-2 (Goldmann applanation). Materials and Methods: IOP was measured in 152 eyes of 76 dogs. A postmortem study was performed by comparing manometry and tonometry values and calculating the correlation coefficient (r2), in vivo real IOP (manometry) among the tonometers was compared, and an outpatient study was conducted with healthy eyes and eyes with signs of glaucoma and uveitis. Results: In the postmortem study, the values of r2 in descending order were Kowa (0.989), TonoVet Plus (0.984), TonoVet (0.981), and Tono-Pen Avia Vet (0.847). The IOP values in mmHg in the in vivo study were as follows: Aneroid manometer (16.8±2.5.7), TonoVet (18.1±2.9), TonoVet Plus (20.6±2.3), Tono-Pen Avia Vet (17.1±2.5), and Kowa (16.1±1.7); in outpatient clinics: TonoVet (16.8±3.8), TonoVet Plus (19.2±2.9), Tono-Pen Avia Vet (16.2±2.4), and Kowa (15.0±1.3); glaucoma: TonoVet (30.2±3.5), TonoVet Plus (35.0±6.1), Tono-Pen Avia Vet (29.5±4.2), and Kowa (23.9±5.0); and uveitis: TonoVet (14.2±1.4), TonoVet Plus (17.6±1.9), Tono-Pen Avia Vet (13.7±2.1), and Kowa (12.6±1.7). Conclusion: There was a strong correlation between IOP values and manometry in all the tonometers. The highest values were obtained with TonoVet Plus and the lowest with Kowa HA-2. All tonometers accurately measured IOP in dogs, including the latest TonoVet Plus, which showed an excellent correlation coefficient.

BackgroundMeasurement of the intraocular pressure (IOP) is a useful diagnostic tool in equine ophthalmology. Handheld tonometers, such as Tonovet and Tonovet Plus (rebound), Tono‐Pen AVIA Vet (applanation), and Kowa HA‐2 (applanation using the Goldmann methodology) are used to obtain IOP measurements in veterinary medicine.ObjectivesTo compare and evaluate the accuracy of four handheld tonometers in measuring IOP using different methodologies in healthy horses.Study designIn vivo experiment and cross‐sectional survey of healthy horses.MethodsIntraocular pressure was measured in 72 eyes of 36 horses. An in vivo study was conducted on sedated horses to compare the real IOP values obtained using manometry versus those obtained using tonometry, and a field study was conducted on unsedated healthy horses with normal eyes to measure the IOP values using different tonometers.ResultsIn the in vivo study, the mean IOP values using ocular manometry was 24.9 ± 4.0 mmHg (range, 20.0–30.0 mmHg). The mean IOP values using tonometry were: Tonovet, 25.7 ± 5.8 mmHg (range 19.5–33.0 mmHg); Tonovet Plus, 24.8 ± 7.1 mmHg (range 13.2–33.2 mmHg); Tono Pen AVIA Vet, 19.2 ± 4.7 mmHg (range 13.1–26.5 mmHg); and Kowa Ha‐2, 24.1 ± 1.2 mmHg (range 22.8–25.8 mmHg). In the field study, the IOP values were: Tonovet, 30.7 ± 5.6 mmHg (range 21.7–38.0 mmHg); Tonovet Plus, 29.6 ± 6.7 mmHg (range 16.2–38.6 mmHg); Tono‐Pen AVIA Vet, 27.3 ± 5.8 mmHg (range 14.6–37.1 mmHg); and Kowa HA‐2, 23.4 ± 2.2 mmHg (range 20.2–28.7 mmHg).Main limitationsThis study included only healthy horses and a limited number of animals in the in vivo study.ConclusionsThere was a strong correlation between the IOP values and manometry for all tonometers. IOP should be estimated using the same tonometer over time, and the bias of the tonometer used, such as overestimation (rebound tonometer) and underestimation (applanation tonometer), should be acknowledged. A normal reference value for each tonometer should be established in horses.

The objective was to perform ocular biometry and ophthalmic examination in dogs of the French Bulldog breed. We evaluated 72 normal eyes of 36 healthy French Bulldog dogs, 20 males and 16 females, aged from 1 to 7 years. Ocular ultrasound was performed in B mode with a 10 MHz linear probe, and the following parameters of ocular biometry were evaluated: horizontal axial diameter (HAD) of the eye, lens thickness (LT), anterior chamber depth (ACD), and vitreous chamber depth (VCD). The ophthalmic exams performed were as follows: Schirmer Tear Test-1 (STT-1), rebound tonometry (Tonovet), Tear Film Break-up Time (TBUT), and Fluorescein Test (FT). The ocular biometry results (mean±SD) in millimeters were: 20.5 ± 0.6 (HAD), 3.8 ± 0.4 (ACL), 7.4 ± 0.3 (LT) and 9.4 ± 0.4 (VCL), and from the ophthalmic exams (mean±SD) were: 24 ± 3.7 (16.5-33.5) mm/min (STT-1), 20.0 ± 3.7 (13.5-27.0) mmHg (rebound tonometry), and 24.4 ± 6.3 (16-40) seconds (TBUT), and FT was negative in all dogs. The obtained results can serve as parameters of normal values of ocular biometry and ophthalmic exams for ambulatory routines, intraocular surgeries, and future ophthalmic studies in this breed.

To compare strip meniscometry and Schirmer tear test 1 results and tear film breakup time between dogs with normal eyes and dogs diagnosed with keratoconjunctivitis sicca. Methods: One-hundred fifty-six eyes of 78 dogs, 88 normal eyes, and 68 eyes diagnosed with keratoconjunctivitis sicca were included in the study. The tests were performed in the following sequence: Schirmer tear test 1 was used to allocate the dogs to the normal or keratoconjunctivitis sicca group, followed by the strip meniscometry test and tear film breakup time measurement. Results: The results (mean ± standard deviation) of the tests in the normal group were as follows: Schirmer tear test 1, 22.75 ± 3.88 mm/min; strip meniscometry test, 10.01 ± 2.35 mm/5 sec; and tear film breakup time, 25.82 ± 5.47 sec. In the keratoconjunctivitis sicca group, the results were as follows: Schirmer tear test 1, 6.10 ± 4.44 mm/min; strip meniscometry test, 3.03 ± 2.62 mm/5 sec; and tear film breakup time, 10.78 ± 4.23 sec. The Spearman correlation coefficient in the keratoconjunctivitis sicca group was very high, with a significant difference between the strip meniscometry test and Schirmer tear test 1 (r=0.848, p<0.001), and moderate and significant between the strip meniscometry test and tear film breakup time (r=0.773, p<0.001). The cutoff for the strip meniscometry test for keratoconjunctivitis sicca was 7.0 mm/5 sec. Keratoconjunctivitis sicca was suspected when the values were <10 mm/5 sec. Conclusions: This study provided strip meniscometry test values from dogs with normal eyes and eyes with keratoconjunctivitis sicca, with high sensitivity and specificity compared with those of the Schirmer tear test 1. In the future, the strip meniscometry test may be another important quantitative test and could complement the gold standard Schirmer tear test for the diagnosis of keratoconjunctivitis sicca in dogs, an excellent animal model for the study of the disease.

Objective: To describe the morphology of the meibomian glands and goblet cells in the palpebral conjunctiva of healthy cats. Animals studied:Five healthy domestic cats without ocular changes that had died from causes unrelated to the study were evaluated.Procedures: Forty samples were collected from upper and lower palpebral conjunctiva and 20 from palpebral fornix region in the nasal corner. The samples were processed for scanning electron microscopy (SEM), transmission electron microscopy (TEM), and histopathology.